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Working with Copper Water-Supply Pipe

Posted by admin on 20/ 11/ 15

This section focuses on installing rigid copper water pipe: It’s strong, easily worked, approved by virtually all codes, and represents nearly 90 percent of residential installations. That noted, you should also consider reading about PEX flexible tubing on p. 279.

Fittings

If you divide fittings into a few categories, their many names start to make sense. Because they do similar things, supply-pipe and DWV fittings often share names.

Fittings join pipes. The simplest fitting is a coupling, which joins two straight lengths of pipe. A reducing coupling joins different size pipes. A repair coupling has no internal stop midway, so it can slide all the way onto a pipe, then slide back over a new piece of pipe inserted to repair a damaged section. A union is a coupling you can disconnect.

Fittings change direction. The most common directional fitting is a 90°elbow, also known simply as a 90 or an ell. For a more gradual turn, use a 45°elbow, also called a 45 or a Vs bend. A street ell is a 90° elbow with one hubless end, which can fit directly into another fitting’s hub. Ditto, a street 45.

Tees join three pipes. Tees (also spelled T’s) allow you to run branch pipes to individual fixtures or fixture groups. Reducing tees accept different size pipes. If you want to sound like a pro, "read a tee” by noting its run (length) dimension first (in inches), then its branch leg. If both ends of the run are the same size, mention that number only once, as in % by h. But if two legs of a tee reduce, cite all three of the tee’s dimensions, for example: a % by h by h.

Adapters join different types of pipe. A

sweat/male adapter has a soldered end and a

Plumbing Safety

► Get a work permit and a copy of current plumbing codes from your local building department. Follow the codes closely; they’re there

to protect you.

► Get a tetanus shot before you start, and dress for dirty work.

► Wear protective eyewear when using power tools, chiseling, soldering, and striking with hammers—in short, for most plumbing tasks. Wear heavy gloves when handling drainpipe and disposable plastic gloves when working with solvent – based cements or soldering. Wear a respirator mask (not a mere dust mask) when soldering or working around existing soil pipes; P100 filters are the standard protection.

► Use only cordless power tools when cutting into supply pipe. If a power tool shorts out in that situation, it could be fatal. О Before cutting into finish surfaces, shut off the electrical power to nearby outlets, and test with a voltage tester,

as shown on p.235, to be sure power is really off.

► Ensure good ventilation when joining pipes because heated solder and solvent-based cements give off noxious fumes. Make sure you have adequate lighting.

► When soldering joints in place, place a nonasbestos flame shield behind the fittings to avoid igniting the wood framing. Have a plant spritzer, filled with water, on hand to dampen the wood if you must solder fittings close to framing; make sure there’s a fire extinguisher on site.

Molten flux or solder can burn you, so be careful.

► When connecting to existing DWV pipes, plan the task carefully. Flush pipes with clean water beforehand and have parts ready so that you can close things up as soon as possible. To avoid weakening nearby joints, be sure to support pipes before cutting them.

► Be fastidious about washing well after handling contaminated waste pipes and chemicals.

► If you smell gas in a home, stop working: Running equipment or doing soldering could spark an explosion. If you can quickly locate the gas shutoff valve outside, shut it off. In any event, clear everyone from the house at once and call the local gas utility.

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Wood Flooring

Posted by admin on 20/ 11/ 15

Wood is a healthful choice for flooring provided that the subflooring, adhesives (if used), and finishes are carefully chosen to be healthful as well. In standard construction, unfinished wood floors are commonly nailed to a formaldehyde-emitting underlayment and then finished with solvent-based finishes that will outgas for many months. Noxious glues may also be used in the installation process.

There are several prefinished engineered flooring systems available that can be applied directly over concrete using a floating floor installation method. When considering a prefinished floor, order a dated sample, product literature, and an MSDS. Manufacturers will publish their underlayment requirements. Most require a vapor barrier of some sort between the underlayment and the flooring product and will state allowable maximum vapor emissions from the subfloor.

In our experience, most factory finishes have proven to be far more durable then any of the more benign finishes available for jobsite application. Furthermore, when a wood floor must be finished onsite the required sanding is a very dusty process, although dust levels can be reduced if you specify that a “dustless” process be used. For “dustless” sanding, a double-filter vacuum called a DCS unit is attached to the floor sander. It can contain up to 90 percent of the dust, making the process less dusty but by no means dustless.

All components of each wood floor application from underlayment to finish must be carefully analyzed. If you can look at both new and older installations that are similar to your proposed application, you will be able to carefully evaluate what the product smells like when it is new and how well it wears over time.

Wood Flooring International offers a complete line of both solid and prefinished engineered flooring using FSC certified wood. Their flooring is engineered to make very full use of the trees harvested. Their American Woods, Monteverde, Pacific Northwest, and Orchard Collections all meet Ei emissions standards (European standards set to limit formaldehyde emissions). These standards would permit up to an estimated 0.14 parts per million of formaldehyde for hardwoods. This is a significantly higher level than is permitted for wood-based products certified by GreenGuard, which sets a limit of 0.05 parts per million.

Prefinished Engineered Wood Flooring Systems

The following wood flooring systems meet stringent European emissions standards:

• Junckers: This is a solid wood engineered flooring system from Denmark that can be applied directly over concrete. It has a factory-applied UV-cured urethane finish and comes in a variety of wood species with trim pieces. Wood comes from a source with managed forestry practices.

• Kahrs: This is a solid wood engineered flooring system from Sweden with a factory-applied UV-cured multilayered acrylic finish. The wear layer is solid %- inch plain sawn. Available in eleven wood species.

• Rappgo: This is a Swedish system manufactured to meet German DIN emissions standards and containing a central layer of low-emissions plywood sandwiched between a top and bottom layer of solid wood. The product is distinctive in that the top wood has long plank length and the flooring holds up well in very dry conditions. It comes with a durable factory processed UV-cured acrylic finish that is fully cured by the time it reaches the jobsite.

Underlayment for Wood Flooring

Interior-grade plywood or particleboard, most commonly used for wood floor underlayment, should not be used anywhere in a healthy house. The following underlayments are acceptable:

• 1- or 2-inch tongue-and-groove wood or rough-sawn lumber laid diagonally.

• Exterior-grade plywood (CDX), if used for underlayment, should be stickered to air out onsite. When used for chemically sensitive persons, it should be sealed with an acceptable vapor-barrier sealant, as specified in this chapter.

Planning

Posted by admin on 20/ 11/ 15

If you’ll be adding or moving fixtures, you’ll need to install pipes, and that will require permits and planning. Start by assessing the condition of existing pipes (see Chapter 1), which you can connect to if they are in good shape. Create a scale drawing of proposed changes, assemble a materials list, and then ask a plumbing-supply store clerk or a plumber to review both. If you’re well organized, clerks at supply stores will usually be glad to help. However, if you need help understanding your existing system, hire a plumber to assess your system. He or she can also explain how to apply for a permit and which inspections will be required.

IS THERE ENOUGH ROOM?

If you’re adding a bathroom, first consider the overall size of the room. If there’s not enough space, you may need to move walls. Layouts with pipes located in one wall are usually the least disruptive and most economical because pipes can be lined up in one plane. On the other hand, layouts with pipes in three walls are rarely sensible or feasible unless there’s unfinished space above or below in which to run pipes.

FIXTURE ROUGH-IN DIMENSIONS

Once you have a general idea if there’s enough room, focus on the code requirements for each fixture, which dictate where fixtures and pipes

I Minimum Bathroom Dimensions

PIPES IN TWO WALLS

PIPES IN ONE WALL

PIPES IN THREE WALLS

FIVE FIXTURES

must go. It would be aggravating and expensive if code inspectors insisted that you move fixtures after finish floors and walls had been put in place. So install fixtures and pipes to conform with code minimums. The drawings on these two pages show typical drainpipe and supply pipe centers for each fixture and, in most cases, minimum clearances required from walls, cabinets, and the like.

On toilets, the horn—the integral porcelain bell protruding from the bottom—centers in the floor flange. The flange, and the closet bend to which it attaches, should be centered 12 in. from the finish wall for most toilets or 1212 in. from an exposed stud wall. Codes require at least 15 in. clearance from the center of the toilet to walls or cabinets on both sides: In order words, install toilets in a space at least 30-in. wide. There must also be at least 24 in. clear space in front of the toilet.

Toilets with 10-in. and 14-in. rough-in dimensions are available to resolve thorny layout issues (such as an immovable beam underneath) or to replace nonstandard toilets. For example, if you replace a wall-hung toilet with a standard

Toilet

I Rough-In Dimensions

Center the toilet drain 12 in. from the finished wall behind the unit. Allow at least 15 in. of clearance on both sides of the toilet, measured from the center of the drain.

(close-coupled) unit, there would be an ugly 2-in. gap between the toilet and the finish wall. By installing a 14-in. rough toilet, whose base is longer, you can use the existing floor flange and eliminate the gap behind the toilet.

Install water-supply risers on the wall behind the toilet, 6 in. above the floor and 6 in. to the left of the drainpipe. If there’s a functional riser sticking out of the floor, use it. But floor risers are seldom installed today because they make mopping the floor difficult. Clearances around bidets are the same as those for toilets.

Lavatories and pedestal sinks should be a comfortable height for users. Typically, lavatory rims are set 32 in. to 34. in. above the finish floor; but if a family is tall, raise the lav. (But if you do, remember to raise drain and supply pipe holes an equal amount.) Codes require at least 18 in. clearance in front of a sink; 24 in. is better.

Lavatory drains are typically 18 in. above the floor and centered under the lavatory, although adjustable P-traps afford some flexibility in positioning drains. Center supply pipes under the lav, 24 in. above the floor, with holes spaced 4 in. on center. Pedestal sink drains are housed in the pedestal, so tolerances are tight; follow the manufacturer’s installation instructions when positioning pipes.

Bathtubs and showers vary greatly, so follow the manufacturer’s guides when positioning the pipes. Most standard tubs are 30 in. to 32 in. wide and 5 ft. to 6 ft. long. Codes require a minimum of 18 in. clearance along a tub’s open side(s); 24 in. is better.

Freestanding tubs have exposed drain and overflow assemblies, so their 112-in. drains can be easily positioned to avoid joists and other design constraints. Standard tubs require a hole approximately 12 in. by 12 in. cut into the subfloor under the tub drain end, to accommodate the drain and overflow assembly. If an existing joist is in the path of the tub drain, you may need to cut through the joist and add doubled headers, as explained further on p. 287.

Positioning supply pipes and valve stems is easier because they’re smaller and typically centered on an end wall—although, again, follow the manufacturer’s rough-in dimensions for code-required pressure-balancing valves and the like. Place the shower arm 72 in. to 78 in. above the floor so taller users won’t need to stoop when taking a shower. Place the tub spout 22 in. high. Tub faucet handles (and mixing valves) are customarily 6 in. above the spout.

1/2-ІП.

water supply

Tub/Shower Rough-In Dimensions

The tub drain and stubs in the end wall should be centered 15 in. from the long wall. Mixing valves are typically set 12 in. above the tub spout, whereas individual valve stems are set 6 in. above the spout, 8 in. o. c., or follow the manufacturer’s recommended rough-in specs.

Double sinks are most often installed in kitchens, so the drain is often offset under one sink, as shown in the drawing on p. 295. Braided stainless-steel supply lines are very flexible, so you can rough-in water supply stub-outs at any convenient height; 18 in. is common.

Kitchen sinks frequently have double basins, so you can center or offset drainpipes. In standard 36-in.-wide base cabinet, the drain is often offset so that it is 12 in. from one cabinet sidewall, leaving room to hook up a garbage disposer. To make cabinet installation easier, have the drain exit into the wall rather than the floor. A drain that exits 15 in. above the finish floor will accommodate the height of a garbage disposal (11 in.) and the average depth (9 in.) of a kitchen sink. Sink faucet holes are typically spaced 8 in. on center, so align supply pipes with their centerline, roughly 2 in. above the drain height. Supply-pipe height is not critical because risers easily accommodate varying heights.

SKETCHING LAYOUTS

Make a separate sketch of each floor’s plumbing; include the basement and attic, too. The easiest way to do this to create an accurate outline of the house’s footprint, using graph paper and a scale of /a in. per 1 ft. Then use tracing-paper overlays for each floor’s plumbing layout. Indicate existing fixtures, drains, supply pipes, water-using appliances, and the water heater. Where pipes are exposed, note the size and dimension of drains and stacks and where the supply pipes exit into

Try to obtain sheets of plumber’s isometric paper so you can show bathroom rough-ins in three dimensions. Art or engineering supply stores may carry the paper, but the Internet is probably a better bet.

the floor above. Especially note the location of 3-in. main drains and vents: If you can cluster fixtures around larger DWV pipes within a room—or from floor to floor—you’ll shorten the distance that fixture drains must travel and thus reduce the amount of framing you may have to cut or drill when running the new pipes.

If you’re moving or adding fixtures, make separate floor sketches for them, too. By laying tracing-paper sketches of old and new plumbing atop each other, you can quickly see if fixtures cluster and, if you’re adding fixtures to an existing system, the closest part of a drain or supply pipe to connect to and extend from. Plumbers use isometric paper to draw pipe runs, as shown in "Plumber’s Isometric Sketch of a Three-Fixture Bathroom,” at left, but any to-scale sketch will give you an approximate idea how long pipe runs will be. Sketches also tell you where you’ll need fittings because the pipes change direction, connect to branches, or decrease in size.

Tools

With a modest tool collection, you’ll be ready for most plumbing tasks.

Pipe wrenches tighten and loosen threaded metal joints, such as %-in. nipples (short pipe lengths) screwed into a water heater, galvanized pipe unions, and so on. A pair of 10-in. or 12-in. pipe wrenches should handle most tasks. Get two: Most of the time, you’ll need one wrench to hold the pipe and the other to turn the fitting.

Adjustable wrenches (also called Crescent wrenches) have smooth jaws that grip but won’t mar chrome nuts and faucet trim. Get several:

A 4-in. adjustable wrench is right for the closet bolts that anchor toilet bowls, a 12-in. wrench gives extra leverage for stubborn nuts, and an 8-in. wrench is appropriate for almost everything else.

Strap wrenches aren’t a must-have tool but are useful when you need to grip polished pipe without scarring it.

Slide-nut (sliding-jaw) pliers are good utility tools for holding nuts, loosening pipe stubs, and holding a pipe section while it’s being soldered.

The jaws of locking pliers (or Vise-Grip pliers) adjust and clamp down on fittings, for example, so you can have both hands free to hold a torch and apply solder.

Basin wrenches are about the only tools that can reach water-supply nuts on the underside of sinks and lavs, where supply pipes attach to threaded faucet stems.

Tub-strainer wrenches tighten tub strainer and tailpiece assemblies.

No-hub torque wrenches tighten stainless – steel band clamps on no-hub couplings. Many

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plumbers use a cordless drill/driver to do most of the tightening, but code requires that final tightening be done by hand.

Pipe cutters (also called wheeled tubing cutters) are the best tools for a clean, square cut on copper pipe. Tighten the cutter so that its cutting wheel barely scores the pipe; then rotate the tool around the pipe, gradually tightening until the cut is complete. Many types have a foldaway deburring tool. Use a close-quarters cutter (thumb cutter) where there’s no room for a full-size one. If you’re installing CPVC plastic supply pipe, use tubing shears for clean, quick cuts. A hacksaw works, but not as well.

A reaming tool (if your cutter doesn’t have one attached) is used to clean metal burrs after cutting copper. Use a round wire brush to polish the inside of copper fittings after reaming and plumber’s sand cloth to polish the pipe ends.

If you’re cutting plastic pipe, use a rounded file to remove burrs—the steel jaws of an adjustable wrench also work well for deburring plastic pipe.

Wide-roll pipe cutters open wide to receive the larger diameters of plastic DWV pipe. Plastic-pipe saws have fine teeth that cut ABS and PVC pipe cleanly—and squarely, if used with a miter box. If you need to cut into cast iron, rent a snap cutter, also known as a cast-iron cutter. It’s the only tool that cuts cast iron easily. Some models have ratchet heads for working in confined places.

A cordless drill and cordless reciprocating saws are must-haves if you’re working around metal pipes that could become energized by electricity and when working in tight, often damp crawl spaces. Old lumber can be hard stuff to drill or cut, so 14.4-volt cordless tools are minimal. Cord
less drills are perfect for attaching plumber’s strap, drilling holes in laminate countertops, and so on.

If you need to drill 2-in. (or bigger) holes, use a corded drill. Heavy-duty drilling takes sustained power and more torque than most cordless drills have. A 12-in. right-angle drill supplies the muscle you need in close quarters.

Cutting and reaming tools. Top row, from left:miniature hacksaw, close – quarters cutter, combo chamfer and reamer (cleans burrs from pipe ends after cutting), and aviation snips. Bottom row:reamer, utility knife, large-wheeled tubing cutter (cuts up to 2-in. plastic pipe), and wheeled tubing cutter. The cutting wheels can be changed for different pipe materials.

Miscellaneous tools. Clockwise, from left:torpedo level, hammer, 14.4-volt cordless drill, flint and steel striker (lights torch), MAPP gas soldering torch, tape measure, and plumber’s sand cloth (used before fluxing pipe).

MAPP (methylacetylene propadiene) gas torches have generally replaced propane units (once popular with do-it-yourselfers) and even larger professional rigs with tanks, hoses, and fancy nozzles. MAPP gas torches are perfect for soldering the ’/2-in. or %-in. fittings encountered most often in house plumbing.

Nonasbestos flame shields protect wood framing when soldering joints. It is also important to have a fire extinguisher nearby.

Your plumbing kit should also include a handful of other tools. Aviation snips are used for cutting perforated strap and trimming gaskets, and a torpedo level helps with leveling stub-outs (pipe stubs protruding into a room), sinks, and toilet bowls. You’ll also want a hacksaw, screwdriver with interchangeable magnetic bits, utility knife, and hammer.

Generation of Univariate Random Numbers for Some Distributions

Posted by admin on 20/ 11/ 15

This section briefly outlines efficient algorithms for generating random variates for some probability distributions commonly used in hydrosystems engineering and analysis.

6.1.2 Normal distribution

A normal random variable with a mean цx and standard deviation ox, denoted as X ~ N(p. x, ox), has a PDF given in Eq. (2.58). The relationship between X and the standardized normal variable Z is

X = ^x + OxZ (6.11)

in which Z is the standard normal random variable having a mean 0 and unit standard deviation, denoted as Z ~ N(0,1). Based on Eq. (6.11), normal random variates with a specified mean and standard deviation can be generated from standard normal variates. Herein, three simple algorithms for generating standard normal variates are described.

Box-Muller algorithm. The algorithm (Box and Muller, 1958) produces a pair of independent N(0,1) variates as

z1 = v/-2ln(u1) cos(2n u2)

______________ (6.12)

Z2 = /-2ln(U2) sin(2nU2)

in which u1 and u2 are independent uniform variates from U(0,1). The algorithm involves the following steps:

1. Generate two independent uniform random variates u1 and u2 from U(0, 1).

2. Compute z1 and z2 simultaneously using u1 and u2 according to Eq. (6.12).

Marsagalia-Bray algorithm. Marsagalia and Bray (1964) proposed an alternative algorithm that avoids using trigonometric evaluations. In their algorithm, two independent uniform random variates u1 and u2 are produced to evaluate the following three expressions:

V1 = 2U1 – 1

V2 = 2U2 – 1 (6.13)

R = V1 + V 22

If R > 1, the pair (u1, u2) is rejected from further consideration, and a new pair (u1, u2) is generated. For the accepted pair, the corresponding standard

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Подпись: The central limit theorem-based algorithm can be implemented as 1. Generate 12 uniform random variates from U(0, 1). 2. Compute the corresponding standard normal variate by Eq. (6.17). There are many other efficient algorithms developed for generating normal random variates using the variable transformation method and AR method. For these algorithms readers are referred to Rubinstein (1981).

normal variates are computed by

BRIDGE RAILINGS AND TRANSITIONS

Posted by admin on 20/ 11/ 15

Bridge railings are longitudinal barriers intended to prevent vehicles from running off the edge of a bridge. A metal post-and-rail system, a concrete safety shape, and various combinations have been used. Bridge railings are attached to the structure and designed to have minimal deflection under impact. The AASHTO Standard Specifications for Highway Bridges require that bridge railings meet specific geometric criteria and resist specified loads without exceeding allowable stresses. However, the AASHTO LRFD Bridge Design Specifications provide the most current design criteria, based on NCHRP Report 350. While AASHTO specifications do not prescribe bridge rail crash testing, the Federal Highway Administration (FHWA) does require that all bridge railings used on the National Highway System be of a crash-tested design. Existing railings designed to prior AASHTO specifications or crash-tested under earlier guidelines may be acceptable through evaluation of in-service performance.

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BRIDGE RAILINGS AND TRANSITIONS AASHTO Designation:

Test Level:

Nominal Barrier Height: Maximum Dynamic Deflection:

Remarks: This barrier is suitable for both permanent and temporary applications, Its primary advantage is that the adjacent pavement can be overlaid several Limes without affecting the performance of the barrier. Its disadvantage is that greater vehicle damage occurs at shallower impact angles compared to other safety-shape barriers.

FIGURE 6.34 Single-slope concrete median barrier. Conversion: 1 in = 25.4 mm. (From Roadside Design Guide, AASHTO, Washington, D. C., 2002 and 2006, with permission)

6.11.1 Selection Considerations

The selection of a railing should include consideration of the following five factors:

Railing performance. There must be evidence that the system will provide the desired performance level. Design to current AASHTO LRFD Bridge Design Specifications and crash-testing to NCHRP Report 350 is recommended. Compatibility. A crashworthy transition section is required if the approach barrier significantly differs in strength, height, or deflection characteristics.

Cost. Life-cycle cost analysis is desirable to compare alternatives. Initial costs, maintenance costs, and the costs of accidents must be considered.

Field experience. Review in-service performance of existing systems to evaluate effectiveness and cost.

Aesthetics. Appearance is particularly important in scenic areas, but systems must be selected that meet required performance levels.

. Install the New Window with Expanders, Shims, and Screws

Posted by admin on 20/ 11/ 15

Different manufacturers have different details for securing and weathersealing their windows. However, they all have a sill expander of some type at the top and bottom, and rely on screws to secure the frame to the jamb.

3. Partially driven screws secure the window for centering.

4. Mounting screws in the window frame are used for the final adjustment.

1. Install the bottom sill expander. Use a

Speed Square® to make a level reference line so that you can measure how much the sill slopes. Then use a utility knife to cut the bottom sill expander to fit snugly against the sill. Tap the expander into the window frame with the butt of a hammer handle.

1. The bottom sill expander is cut to fit against the sloping sill.

2. Install the head expander. If the replacement window doesn’t overlap the head stop, you need to add the head expander that fits over the top of the window and fill the airspace with low-expanding foam or fiberglass insulation.

5. The inside sash stop is removed and reused as molding around the new window.

. Install the New Window with Expanders, Shims, and Screws

homeowners, but many local fabricators have a retail store on site that will sell you windows at a small premium over wholesale prices.

You can also buy replacement windows at a home center. If your house is 50 years old or less, you can find fairly good-quality
windows in standard sizes to fit the existing openings.

I advise shopping around, but be sure you’re comparing equal products and services. Some companies’ standard features are options that cost more from other fabricators. Frame thickness and extrusion designs

. Install the New Window with Expanders, Shims, and Screws
3. Insert and center the window. Drive two mounting screws partway through the window frame and into the jambs to keep the window in place. Then use a small pry bar to get the frame centered, level, and plumb.

. Install the New Window with Expanders, Shims, and Screws

4. . Install the New Window with Expanders, Shims, and Screws Подпись: 5. Replace the sash stops. The payoff for removing the old stops carefully is that they can be reused to finish the new window. Before installing the stops, I fill gaps between the window and the jamb with low-expanding foam, part of the weathersealing process (see the sidebar on p. 116). . Install the New Window with Expanders, Shims, and Screws
Secure the window. Insert shims between the window and the jamb as backing for mounting screws. drive mounting screws in all the pilot holes. sometimes these holes are concealed by sash stops or balance guards that can be slid out of the way or removed.

can differ. Bargain windows might have lower-quality frames that require more time to shim and brace adequately for proper operation.

If I have a choice, I use high-quality vinyl windows made locally. Although they might not be a popular name brand, the warranty

is good (20 years) and the price is reasonable. Also, if problems arise, there’s someone local to call.

Get Maximum Value with a Good Weatherseal

Подпись: Caulk the stops. Apply exterior caulk to the blind stop before installing the swindow; then caulk all the exterior trim joints.

. Install the New Window with Expanders, Shims, and Screws

If I’ve spent the money, time, and effort to replace a window, I want to get the best performance I possibly can. Proper weathersealing calls for spray foam and caulk.

Foam the gaps. Use low-expanding foam to fill gaps between the old jamb and the new window.

Accurate Measurements Are Critical

I always take measurements myself, and if the sales rep comes out to help, I check that person’s work. The last thing I want is to show up on the morning of a whole-house window replacement and find out that someone else messed up the order.

Most important is checking top, bottom, middle, and diagonally for square. The new window has to be sized for the shortest measurement (see the drawing on p. 112).

I use a systematic approach with my own order sheet to note dimensions and location.

Writing measurements on a block of wood just doesn’t cut it. One wrong measurement, and you own a perfectly good window that doesn’t fit.

Know How the Windows Are Sized

Replacement-window fabricators make units on a VWn. basis, a 1/2-in. basis, or a combination of the two. This guideline forces you to order a unit smaller than anticipated when a dimension falls on a 1/8-in. increment, but undersizing a window is better than having it too tight. Window height is more forgiving than width due to the sill and head

1	Choose the Right Window
	any manufacturers that make windows for new construction also make replacement windows. In addition to the factors listed below, you’ll need to consider cost and
	warranty details.
	Style	Wood
	Double-hung, single-hung, casement, awning,	• Requires painting
	and other window styles are available.	• Compatible with historic houses
	Glass	Fiberglass
	The choices include different types of insu-	• Stronger than vinyl and just as durable
	lated glass, such as glass with heat-reflective	• Available with wood interior surfaces
	coatings and gas-filled glass. You can also	• Low maintenance
	order windows with snap-in grilles or true	• Usually more expensive than other types
	divided lites.	Aluminum-clad
	Material	• Durable exterior, wood interior
	The type of material used in the window deter-	• Many colors available
	mines its price, its durability, and its appear-	• Aluminum can be painted
	ance. Here’s a quick tour:	Vinyl-clad
	Vinyl	• Durable exterior
	• Usually less expensive than other types	• Wood or finished interior
	• Durable, low maintenance • Limited color choice	• Limited color choice

expanders, which is why many fabricators offer V4-in. width sizing and only V2-in. height sizing. If I have to choose between leaving only V8 in. of wiggle room or having s/8 in. to play with, I’ll take the bigger measurement.

Some window fabricators take orders based on opening measurements, and they make the deductions to actual unit size from information you supply. I never order this way because it does not account for out-ofsquare conditions. Make your own deductions from the measured opening, and order the actual window size (sometimes called tip-to-tip size).

Guarantee a Smooth, Safe Installation

Wherever I start, I move the furniture out of the way for clear access to the window, and I cover the floor with a drop cloth to collect paint chips and debris. I always use a vacuum and a dust brush to clean out the windowsill and to clean up the floor when I’m done working.

Mike Guertin (www. mikeguertin. com) is a builder, remodeling contractor, and writer in East Greenwich, R. I.

FLASHING ABUTTING MEMBERS

Posted by admin on 20/ 11/ 15

WALL

cap +

2 IN. 2 IN.

this horizontal joint is best protected with A flashing made to fit over the sheathing and moisture BARRIER of THE framed wall.

wood cap with sloped top

p. t. furring screwed to underside of wood cap

DRIP

trim fastened through siding to furring & WALL

siding

moisture barrier continuous over top of wall

sheathing

WALL FRAMING

WIDTH

FRAMED

WALL

note

this detail has a continuous moisture

BARRIER oVER THE TOP oF THE WALL WITHouT penetrations. the moisture BARRIER MAy BE replaced with metal flashing.

WALL cAP see 1050

FLASHING ABUTTING MEMBERS

WINDOW HEAD SEE 103B & C

TOP EDGE SEE 107B

BOTTOM EDGE SEE 107C

TOP EDGE SEE 107B

INSIDE CORNER SEE 104C

FLASHING ABUTTING MEMBERS

Many of today’s common exterior wall finishes have been protecting walls from the weather for hundreds of years. Others such as plywood, hardboard, and vinyl have been developed more recently. Regardless of their history, when applied properly, each is capable of protecting the building for as long as the finish material itself lasts.

If possible, the best way to protect both the exterior finish and the building from the weather is with adequate overhangs. But even then, wind-driven rain will occasionally get the building wet. It is important, therefore, to detail exterior wall finishes carefully at all but the most protected locations.

The introduction of effective moisture barriers under the siding has the potential to prolong the life of walls beyond the life of the siding alone. While the siding is still the first line of defense against weather, it is possible to view one of its primary functions as keeping sunlight from causing the deterioration of the moisture barrier, which ultimately protects the walls of the building.

Where the moisture barrier stops—at the edges and the openings through the wall—special attention must be paid to the detailing of exterior wall finishes.

Sealants—In this country alone, there are more than 200 manufacturers of 20 different types of caulks and sealants. However, the appropriate use of sealants for wood-frame buildings is limited for two reasons. First, sealants are not really needed—there are 200-year-old wooden buildings still in good condition that were built without the benefit of any sealants. Second, the lifespan of a sealant is limited—manufacturers claim only 20 to 25 years for the longest-lasting sealants. Therefore, it is best practice to not rely heavily on the use of sealants to keep water out of buildings.

However, some situations in wood-frame construction do call for the use of a sealant or caulk. These are mostly cases where the sealant is a second or third line of defense against water intrusion or where it is used to retard the infiltration of air into the building. In all instances, it is recommended that the caulk or sealant not be exposed to the direct sunlight.

@ EXTERIOR WALL FINISHES

A VERTICAL EDGE IS A LIKELY PLACE FOR WATER TO LEAK AROUND THE EXTERIOR WALL

finish into the structure of a building. a continuous moisture barrier behind the vertical joint is crucial. a sealant can help deter the moisture, but will deteriorate in the ultraviolet light unless placed behind the wall finish,

WHERE IT WILL BE PRoTEcTED.

AT THE upper edges of WALL FINisHEs (AT eaves & rakes, under windows & doors & at other horizontal breaks), direct moisture away from the top EDGE of THE finish MATERIAL To THE face of the wall.

FLASHING ABUTTING MEMBERS

if siding is to be painted.

Horizontal

Material

Change

Sills, Eaves & Other Overhangs

EXTERIOR WALL FINISHES

At Vertical Edges

EXTERIOR WALL FINISHES

At Top Edges

FLASHING ABUTTING MEMBERS

the bottom edge of the wall finish is more

LIKELY to GET WET THAN THE TOP. ALLoW WATER

to fall from the bottom edge of the wall finish in a way that avoids capillary action.

FLASHING ABUTTING MEMBERS

porch

: .. or deck

! s

foundation roof

or other

MATERIAL

EXTERIOR WALL FINISHES

At Bottom Edges

FLASHING ABUTTING MEMBERS

Horizontal wood siding is common in both historic and modem buildings. The boards cast a horizontal shadow line unique to this type of siding.

Materials—Profiles (see below right) are commonly cut from 4-in., б-in., and 8-in. boards. Cedar, redwood, and pine are the most typical. Clear grades are available in cedar and redwood. Many profiles are also made from composite hardboard or cementboard. These materials are much less expensive than siding milled from lumber and are almost indistinguishable from it when painted.

A HORIZONTAL SIDING

Drop Shiplap T & G Bevel

Horizontal Siding Profiles

Types—Siding joints may be tongue and groove, rabbeted, or lapped. Common profiles (names may vary regionally) are illustrated at bottom right.

Application—Boards are typically applied over a moisture barrier and sheathing, and should generally be back-primed before installation. Boards are face – nailed with a single nail near the bottom of each board but above the board below to allow movement. Siding is joined end to end with miter or scarf joints and sealant over a stud.

Finish—Horizontal wood siding is usually painted or stained. Clear lumber siding is sometimes treated with a semitransparent stain.

FLASHING ABUTTING MEMBERS
Rain Screen Siding—Rain screen siding strategy recognizes that some moisture will penetrate the wall and provides an easy path for this moisture to escape the wall assembly. A rain screen wall can be understood as two layers of protection with an air space in between.

An outer layer sheds most of the weather, and an inner layer takes care of what little moisture gets through.

The critical element—one that is not present in (most) other siding systems—is the air space between the two layers. This air space provides a capillary break and promotes the rapid escape of moisture with a clear path to the base of the wall for water to drain by gravity and by allowing ventilation to remove moisture in the form of water vapor.

Materials—The inner layer can be made of the same materials as the moisture barrier in most siding systems: tar paper, building wrap, or rigid foam insulation in conjunction with flashing (and tape or sealant). The air space is created by vertical furring strips, usually 3/8 in. to У2 in. thick aligned over the studs. The
outer layer is usually made with horizontal wood siding (clapboards), but can be made of any material that sheds water and is capable of spanning between the vertical furring strips. Screening is required at the top and bottom of the wall to keep insects out of the air space.

Application—Materials are applied with nails or staples as with standard siding materials. Special care should be taken that materials lap properly to shed water. The inner layer, called the drainage plane, must be especially carefully detailed and constructed to keep moisture out of the framing. Back-priming and endpriming of wood siding materials is very important to prolong the life of the material and of the finish.

Finish—Rain screen siding can be finished with any paint or stain designed for use on standard siding. Because the system breathes and does not trap moisture within the wall, finishes will typically outlast the same finish applied to a standard wall.

FLASHING ABUTTING MEMBERS

@ RAIN SCREEN SIDING

trim may BE ELIMINATED at horizontal TOP

Подпись: LAP INSIDE CORNERS. FIRST PIECE MAY BE HELD AWAY FROM CORNER TO ALLOW FOR MOISTURE BARRIER. Подпись: TRIMMED WITH LAPPED BATTENS IN BOARD & BATTEN Подпись: BOTTOM EDGE PROJECTS BELOW SHEATHING TO FORM DRIP AT FOUNDATION. Подпись: OR RABBET OR BEVEL ON REAR SIDE FORMS DRIP AT HORIZONTAL SURFACES. FLASHING ABUTTING MEMBERS Подпись: OUTSIDE CORNERS LAPPED _ OR EDGES If SIDING IS OIT cAREFuLLY TO FIT UNDER SILLS OR EAVES.

FLASHING ABUTTING MEMBERS matched SIDING MAY BE TRIMMED

with second

FLASHING ABUTTING MEMBERS Подпись: Rake Details

LAYER, OR BOARD SIDING WITH HORIZONTAL BATTEN.

top edges (soffit trim, eave TRIM & under SILLS) TRIMMED WITH under SILL TRIM INTO WHicH SIDING SLIDES. SPEQAL TooL

Подпись: VERTICAL EDGES (CASINGS) ARE TRIMMED WITH SIDE CHANNEL INSTALLED BEFORE SIDING & INTO WHICH SIDING SUDES (RAKE RIMMED WITH SAME CHANNEL) Подпись: OUTSIDE CORNERS ARE A vARIATioN OF THE BASIC CHANNEL & COVER THE ENDS oF THE SIDING FLASHING ABUTTING MEMBERS punches tabs at cut top

EDGE oF SIDING; TABS Lock

into trim, which may need to be furred depending on location of horizontal cut

IN SIDING.

Vinyl sidings were developed in an attempt to eliminate the maintenance required of wood sidings. Most aluminum-siding manufacturers have moved to vinyl.

Material—There are several shapes available. Most imitate horizontal wood bevel patterns, but there are some vertical patterns as well. Lengths are generally about 12 ft., and widths are 8 in. to 12 in. The ends of panels are factory-notched to allow for lapping at end joints, which accommodates expansion and contraction. Color is integral with the material and ranges mostly in the whites, grays, and imitation wood colors. The vinyl will not dent like metal, but will shatter on sharp
impact, especially when cold. Most manufacturers also make vinyl soffit material, and some also make decorative trim. Vinyl produces extremely toxic gasses when involved in a building fire.

Installation – Vinyl has little structural strength, so most vinyl sidings must be installed over solid sheathing. Proper nailing with corrosion-resistant nails is essential to allow for expansion and contraction. Because vinyl trim pieces are rather narrow, many architects use vinyl siding in conjunction with wood trim, as suggested in the isometric drawing above.

@ VINYL SIDING

TOP EDGES ARE SOMETIMES LEFT WITHOUT TRIM BECAUSE THEY CAN EASILY BE CUT TO A CLEAN SQUARE EDGE THAT IS BUTTED AGAINST A SoFFIT, EAvE, or other horizontal surface, or trim may be added.

horizontal joints between siding PANELS oR between PANELS & oTHER MATERIAL SHoULD BE blocked if they do not occur over a plate or floor framing.

LAP PANELS To FoRM A DRIP EDGE oR

BUTT PANELS AND FLASH WITH METAL z FLASHING,

SEE 104A

vertical joints BETWEEN SIDING PANELS SHoULD ALWAYS FALL ovER A STUD.

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manufactured

LAP joiNT

butt joint covered

WITH BATTEN

FLASHING ABUTTING MEMBERS

Materials— Plywood siding is available in 4-ft.-wide panels, 8 ft., 9 ft., and 10 ft. tall. Typical thicknesses are 3/s in., V’2 in. and 5/s in. The panels are usually installed vertically to avoid horizontal joints, which require blocking and flashing. Textures and patterns can be cut into the face of the plywood to resemble vertical woodsiding patterns.

Installation—Manufacturers suggest leaving a Vs-in. gap at panel edges to allow for expansion. All edges should be treated with water repellent before
installation. It is wise to plan to have window and door trim because of the difficulty of cutting panels precisely around openings. Fasten panels to framing following the manufacturer’s recommendation.

Single-wall construction—Since plywood, even in a vertical orientation, will provide lateral bracing for a building, it is often applied as the only surface to cover a building. This is called single-wall construction and has some unique details (see 80 and 113).

Подпись: NO SHEATHING BENEATH PLYWOOD, SO PLYWOOD DOES NOT FORM DRIP AT BOTTOM EDGE. SEALANT MAY BE BETTER THAN NOTHING IN SOME SITUATIONS.

Most of the details for double-wall plywood construction also apply to single-wall construction. But with single-wall construction, the moisture barrier is applied directly to the framing, making it more difficult to achieve a good seal. The wide-roll, polyolefin mois – ture/air infiltration barriers work best (see 88B). Also, the bottom edge of the plywood is flush against the foundation, so a drip detail is impossible (see right).

Flashing—Windows and doors that are attached through the casing and need head flashing because of exposure to rain or snow are very difficult to flash. As shown in the drawings below, a saw kerf must be cut into the siding at the precise location of the flashing. The flashing and siding must be installed simultaneously before the door or window is attached.

Подпись: Section Flashing a Header

FLASHING ABUTTING MEMBERS

COVER HORIZONTAL EDGES WITH TRIM FASTENED TO A SPACER. LOCATE SHINGLE FASTENERS VERY HIGH ON LAST cOuRSE

NOTE

SHORT HORIZONTAL EDGES SUCH AS APRONS MAY BE COVERED WITH A PIECE OF TRIM FASTENED TO THE SLOPED SURFACE OF THE SHINGLES. FOR RAKE TRIM. SEE 115A & B

FASTENERS 1 IN. (MIN.) ABOVE COURSE LEVEL OF NEXT COURSE

shingles
butt TO
VERTICAL

TRIM

JOINTS BETWEEN SHINGLES OFFSET 11/2 IN. (MIN.) FOR THREE ADJACENT COURSES.

1A-IN. SPACE BETWEEN ADJACENT SHINGLES IN FIELD (NOT AT CORNERS OR EDGES)

DOUBLE
BOTTOM
COURSE
PROJECTS
1/2 IN. BELOW
SHEATHING TO
FORM DRIP.

OUTSIDE CORNERS ARE WOVEN SO ALTERNATE ROWS HAVE EDGE OF SHINGLE EXPOSED.

EDGE IS TRIMMED FLUSH WITH ADJACENT SHINGLE ON OPPOSITE FACE OF CORNER. CORNER BOARDS CAN ALSO BE USED AS TRIM AT OUTSIDE CORNERS. SEE 110 .

INSIDE CORNERS ARE WOVEN LIKE OUTSIDE CORNERS.

SHINGLES ARE TRIMMED TO BUTT AGAINST SHINGLE ON OPPOSITE FACE. TOP SHINGLE ALTERNATES FROM ROW TO ROW. CORNERBOARDS CAN ALSO BE USED AS TRIM AT INSIDE CORNERS. SEE 110

FLASHING ABUTTING MEMBERS

Shingles are popular because they can provide a durable, low-maintenance siding with a refined natural appearance. Shadow lines are primarily horizontal but are complemented with minor verticals. Material costs are relatively moderate but installation costs may be very high.

Materials—Shingles are available in a variety of sizes, grades, and patterns. The most typical is a western red cedar shingle 16 in. long. Redwood and cypress shingles are also available. Because shingles are relatively small, they are extremely versatile, with a wide variety of coursings and patterns.

Installation—Shingles are applied over a moisture barrier to a plywood or OSB wall sheathing so at least two layers of shingles always cover the wall. Standard

coursing allows nail or staple fasteners to be concealed by subsequent courses. With shingles there is less waste than with other wood sidings.

Finish—Enough moisture gets between and behind shingles that paint will not adhere to them reliably.

Left unfinished, they endure extremely well, but may weather differentially, especially between those places exposed to the rain and those that are protected.

Stains and bleaching stains will produce more even weathering.

Preassembled shingles—Shingles are also available mounted to boards. These shingle boards increase material cost, decrease installation cost, and are most appropriate for large, uninterrupted surfaces. Corner boards are required at corners.

@ WOOD SHINGLE SIDING

CEDAR SHINGLES

MITER TOP TRIM PIECE.

SECOND PIECE OVERLAPS FIRST.

START AT BOTTOM OF RAKE WITH BOARD RIPPED TO THIcKNESS

of butt end of shingles. TOP END is cut level & FITS uNDER SHINGLE (SEE ISOMETRIc AT RIGHT).

Elevation

ONE Method OF FINISHING THE TOP EDGE OF A SHINGLE wALL IS TO LAP THE SHINGLE cOuRSES wiTH TRIM PIEcES RIPPED FROM A cEDAR 2x. IF THE cOuRSING IS EQuAL, ALL THE TRIM PIEcES, ExcEPT FOR THE MITERED TOP PIEcES, wILL ALSO BE EQuAL.

SHINGLE SIDING AT RAKE

Lapped Trim

THE BASE Layer IS NOT ExPOSED & THEREFORE

can be a lower-grade

SHINGLE.

FINISH-LAYER SHINGLE

projects about 1/2 IN.

BELOw BASE LAYER TO FORM A DRIP.

RIP SHINGLES TO DESIRED wIDTH & APPLY AT SAME cOuRSING AS

FLASHING ABUTTING MEMBERS

NAILING MuST BE EXPOSED FOR THIS cOuRSING.

NOTE

FOR PREPAINTED OR PRIMED SHINGLES, LEAVE NO SPAcE BETwEEN FINISH LAYER SHINGLES.

DOuBLE cOuRSING, AN ALTERNATIVE cOuRSING METHOD, cALLS FOR TwO LAYERS APPLIED AT THE SAME cOuRSE. A PREPAINTED OR PRIMED SHINGLE cALLED SIDEwALL SHAKE IS cOMMONLY uSED.

Shingled Trim

FLASHING ABUTTING MEMBERS

SHINGLE SIDING AT RAKE

DOUBLE-COURSED SHINGLES

Shingled & IxTrim

Подпись: BRICK & SIDING CORNER SEE 117A Подпись: WINDOW & DOOR OPENINGS SEE 117C FLASHING ABUTTING MEMBERS

Brick veneer covers wood-frame construction across the country. Where it is not subjected to moisture and severe freezing, it is the most durable exterior finish.

Materials—Bricks come in a wide variety of sizes, with the most common (and the smallest) being the modular brick (2>4 in. by 35/s in. by 75/s in.). These bricks, when laid in mortar, can follow 8-in. modules both horizontally and vertically. Colors vaiy from cream and yellows to browns and reds, depending on the clay color and method of firing. Bricks should be selected for their history of durability in a given region.

Installation— Bricks are laid in mortar that should be tooled at the joints to compress it for increased resistance to the weather. Because both brick and mortar are porous (increasingly so as they weather over the years), they must be detailed to allow for ventilation and drainage of the unexposed surface. A 1-in. air space between the brick and the wood framing, with weep holes located at the base of the wall, typically suffices (see 117B). It is important to keep this space and the weep holes clean and free of mortar droppings to ensure proper drainage.

TOP OF WALL IS DETAILED TO KEEP WATER OFF THE HORIZONTAL SuRFAcE OF THE TOP BRIcK. THIS cAN

usually be accomplished with the detailing OF

THE ROOF ITSELF. cOvER THE JOINT BETWEEN BRIcK & ROOF WITH WOOD TRIM. cAuLK THE jOINT AS FOR vERTicAL jOINTS, BELOW.

FLASHING ABUTTING MEMBERS

RAKE TRIM LAPS BRIcK

SEALANT BETWEEN WOOD & BRIcK

RAKE IS uSuALLY TRIMMED WITH WOOD

sufficiently WIDE TO cover the stepping OF brick caused BY SLOPE. DETAIL AS FOR TOP OF WALL.

FLASHING ABUTTING MEMBERS

SHEATHING AIR SPAcE brick

BAcKER ROD SEALANT

vertical casing OR

TRIM OF WOOD OR OTHER MATERIAL

vERTicAL jOINTS Such AS WINDOW & DOOR cASINGS AND AT TRANSITIONS TO OTHER MATERIALS MuST BE cAREFuLLY cAuLKED TO SEAL AGAINST THE WEATHER. BAcKPRIME WOOD cOvERED BY OR

in contact with brick.

Finish – A number of clear sealers and masonry paints can be applied to the finished masonry to improve weather resistance, but reapplication is required eveiy few years.

@ BRICK VENEER

BOTH INSIDE & OUTSIDE CORNERS CAN BE MADE SIMPLY WITH THE BRICKS THEMSELVES.

Brick Corner

FLASHING ABUTTING MEMBERS

IF WooD

Brick and Siding Corners

BRICK VENEER

Corners

FLASHING ABUTTING MEMBERS

FLASHING ABUTTING MEMBERS Подпись: Side Jamb

sill preprimed on underside if wood

sealant between SILL and brick.

rowlock brick sloped at angle of SILL

FLASHING coNTINuouS to back of SILL

SHEATHING 15-LB. FELT 1-IN. AIR SPAcE

BRICK VENEER AT WINDOW/DOOR

Attachment to Casing & Sill

CONTROL JOINT ORIENTED HORIZONTALLY OR VERTICALLY &

LOCATED OVER STRUCTURAL MEMBERS & DIAPHRAGMS BREAKS STUCCO PANELS INTO 18-FT. (MAX.) DIMENSIONS (OR LENGTH-TO-WIDTH RATION OF 2.5И). ——

SELF-FURRING GALVANIZED 17-GAUGE 11/2-IN. MESH STUCCO WIRE (SHOWN) OR GALVANIZED EXPANDED METAL LATH

15-LB. FELT BOND BREAK

Stucco is made of cement, sand, and lime. It is usually applied in three coats, building to a minimum thickness of 3/4 in. Cost may be moderate in areas with high use, but high where skilled workers are few.

Materials— Reinforcing materials through which the plaster is forced are either stucco wire or metal lath. This reinforcing is fastened either to sheathing or directly to the framing (without sheathing). When sheathing is used, it must be rigid enough to remain stiff during the process of applying the stucco—5/s-in. plywood is typical.

A double-layer moisture barrier between the reinforcing and the framing is important because the stucco will bond with the outer layer of barrier, destroying its ability to repel water. The outer layer forms a bond

break so that the inner layer will remain intact to protect the framing. The inner layer performs best if it is thick, with drainage channels.

Application – The first (scratch) coat has a raked finish, the second (brown) coat has a floated finish, and the final (color) coat may have a variety of finishes. Applying stucco takes skill, so stucco is the least appropriate of all the exterior wall finishes for owner-builders to attempt.

Finish—Textures ranging from smooth to rustic are achieved by troweling the final coat. Color may be integral in the final coat or may be painted on the surface. Stucco is not very moisture resistant and must be sealed or painted.

Подпись: FLASHING ABUTTING MEMBERS CASING BEAD AT TOP,

SIDE, OR RAKE EDGES

WRAPPED BASE COAT WITH FIBERGLASS MESH

FINISH COAT WITH INTEGRAL COLOR

BASE COAT WITH EMBEDDED FIBERGLASS MESH

RIGID INSULATION

with grooved back

FLASHING ABUTTING MEMBERS

Synthetic stucco looks like traditional stucco but is really a flexible acrylic coating applied over rigid insulation. Called EIFS (Exterior Insulation and Finish

Systems), synthetic stucco is more flexible than standard stucco and more moisture resistant. This moisture resistance, which certainly is a strength of the system, worked against early versions of its application when imperfect detailing led to moisture being trapped inside the wall behind the impermeable EIFS layer. With updated water-managed EIFS, it is now assumed that some moisture will penetrate the surface, and therefore a drainage path is provided for this moisture to escape.

Materials—There are several manufacturers of water – managed EIFS. Each starts with rigid insulation, fastened to the framing with nails fitted with large plastic washers designed to prevent crushing of the insulation. The insulation is protected from impact by a stucco
base made of acrylic cement reinforced with fiberglass mesh. An acrylic finish coat with integral color provides moisture protection.

Application—All systems start with an effective moisture barrier applied to the wall sheathing. The next layer is a drainage plane that provides a clear path for moisture to escape. This drainage plane can be a separate plastic drainage mat or vertical grooves integrated into the back side of the rigid insulation, which is the following layer. The base coat of stucco is troweled directly onto the insulation, reinforced with mesh, and then another layer of base coat. The final coat is troweled over the hardened base coat.

Finish—There are a variety of common troweled finish textures. Color is integral in the final coat, so painting is unnecessary, but inspection and repair of sealant joints every few years is highly recommended.

FLASHING ABUTTING MEMBERS Wall insulation is typically provided by fiberglass batts. Building codes in most climates allow 2×4 walls with ЗУ2 in. of insulation (R-ll) or 2×6 walls with 5V2 in. of insulation (R-19).

Vapor retarder—Vapor retarders are installed in conjunction with wall insulation. The purpose of a vapor retarder, a continuous membrane located on the warm side of the insulation, is to prevent vaporized (gaseous) moisture from entering the insulated wall cavity, where it can condense, leading to structural or other damage.

Common vapor retarders include 4- or 6-mil polyethylene film applied to the inside of framing or specially formulated paint or primer applied to the surface of chywall.

Rigid insulation with taped

, , , RETARDER WARM

joints may also be used.

Various vapor retarder materials have different rates of permeability (see 88A), and, because moisture can enter a wall assembly from either side, it is wise to use the most permeable material proven to be effective in a given region so as not to trap moisture within the assembly.

The vapor retarder should always be located on the warm side of the insulation. In a cold, chy climate the
retarder goes on the inside of the wall. But in mixed climates the migration of vapor can reverse in the summer. For this reason, building scientists recommend against using low-permeability materials on the inside of air-conditioned walls.

The location of the vapor barrier may be adjusted in upgraded applications provided that two-thirds or more of the insulative value of the wall remains to the cold side of the barrier.

FLASHING ABUTTING MEMBERS

АІГ barrier— An air barrier is intended to control the migration of air through the insulated envelope of a building. Standard construction practices allow voids and breaks in the building envelope that can leak up to two times the total air volume of the building per hour—accounting for up to 30% of the total heat loss (or gain) of the building. Upgrading the envelope can cut this air leakage to one-third of an air change per hour and can thus have significant consequences for energy bills in most climates.

An effective air barrier combines a continuous membrane with tight seals around openings such as windows where the membrane is penetrated. It may be made of a variety of materials and may be located either inside or outside of the insulation. When inside the insulation, the barrier may be chywall, rigid insulation, or the same film that forms a vapor retarder. Outside the insulation, building wrap, rigid insulation, or sheathing may be used. In each case, joints are taped or overlapped and caulked, and tight seals are made with floor and ceiling air barriers. Windows, doors, electrical, plumbing, and other services that penetrate the membrane are sealed with expansive foam, caulk, and/or special tape.

It is important to consider that the reduced ventilation rate due to control of air leakage can lower indoor air quality. The provision of controlled ventilation with simple energy-saving devices such as air-to-air heat exchangers can alleviate this problem.

FLASHING ABUTTING MEMBERS Unfaced batts—The most common method of insulating walls is to use unfaced batts that are fitted between studs. A vapor retarder is applied to the warm side of the wall in the form of a vapor retarding paint or primer or a 4-mil polyethylene film. Properly detailed, this vapor retarder can serve as the air barrier.

FLASHING ABUTTING MEMBERS

Faced batts – Batt insulation is often manufactured with a paper facing that, in cold climates, serves as both vapor retarder and means of attachment. For attachment, the facing material has tabs that are stapled in place between the studs.

FLASHING ABUTTING MEMBERS

To use the facing as a vapor retarder, it is better to staple the tabs to the face of the studs to make a better seal. However, this interferes with the installation of interior finish materials because the tabs build up unevenly on the face of the studs.

Rigid insulation—In

standard construction, rigid insulation is generally used only in extreme situations where wall depth is limited but a code-prescribed R-value is required. Examples of such situations include headers (see 76A & B) and locations where heat ducts, vents, or plumbing must be in exterior walls. In upgraded framing systems, however, rigid insulation is used extensively (see 122A).

Spray-foam insulation—It can cost many times as much as competing insulations, but spray-foam insulation can equal the R-value of the best rigid foam, double as a vapor retarder, and fully fill the most awkwardly shaped framing cavity. Except for its high cost, it is a nearly ideal insulating material for mixed climates where warm and cold sides of the envelope reverse during the year.

In climatic zones with extremely cold or hot weather (or high utility rates), there is special incentive to insulate buildings beyond code minimums. A decision to super – insulate affects the construction of walls more than floors or roofs because walls are generally thinner (being constructed of 2x4s or 2x6s rather than 2x10s or 2x12s). Walls are also in direct contact with the ambient air because they do not have a crawl space or attic to intervene as a buffer.

The most direct way to increase the insulative capacity of walls is to make them thicker. A 2×4 framed wall upgraded to 2×6, for example, will increase from a combined (batt plus framing) R-value of 9.0 to a value of R-15.1. But increasing wall thickness alone is only effective to a point because a significant part of the wall (about 9% of a wall framed at 24 in. o. c.) is composed of studs, plates, etc., which conduct heat at about three times the rate of insulative batts. When headers and other extra framing are considered, walls often have as much as 20% of their area devoted to framing. The conductance of heat through this framing is called thermal bridging.

There are two strategies for decreasing the effects of thermal bridging. The first is to reduce the quantity of framing members and is called advanced framing (see 74). The second strategy is to insulate the framing members that remain so that they do not “bridge” between the cold and warm sides of the wall. Several ways to insulate framing members are discussed on the following pages.

Rigid insulation—Rigid insulation added to the exterior or interior of a framed wall can typically add an R-value of 7 to 14 at the same time that it interrupts thermal bridging (see 122).

Strapping—Horizontal nailing strips are attached to the inside of a stud wall. Insulative values of R-25 are easily attainable (see 123).

Staggered-stud framing—A double offset stud wall framed on a single, wide plate. Combined insulative values of R-30 are common (see 124).

Double wall framing—A duplicate (redundant) wall system with R-values of up to 40 is easily reached (see 125).

FLASHING ABUTTING MEMBERS

PLACEMENT OF BARRIERS ON SLOPED MEDIANS

Posted by admin on 20/ 11/ 15

Either roadside barriers or median barriers may be appropriate for sloped medians, depending on conditions. If a relatively flat median (slope of 1:10 or flatter) free of rigid objects is available, a median barrier can be placed at the center. When such desirable conditions are not available, some additional guidelines should be considered. Figure 6.36 shows three basic types of median sections. Section I (illustrations 1-3) represents a depressed median or one with a ditch; section II (illustrations 4-6) represents a stepped median or a median that separates traveled ways with significant differences in elevation; and section III (illustration 7) applies to a raised median.

Section I. Check to see if the slopes warrant a barrier. If both slopes require shielding (illustration 1), place a roadside barrier near the shoulder on each side of the

PLACEMENT OF BARRIERS ON SLOPED MEDIANS

FIGURE 6.32 Tall-wall concrete safety-shape (reinforced) median barrier. Conversion: 1 in = 25.4 mm. (From Roadside Design Guide, AASHTO, Washington, D. C., 2002 and 2006, with permission)

median. If only one slope must be shielded, place a median barrier near the shoulder on that side; use a rigid or semirigid barrier, and install a rub rail on the ditch side of the barrier to prevent snagging of a vehicle that has crossed the ditch. If neither slope requires shielding but one is steeper than 1:10 (illustration 2), place a rigid or semirigid median barrier on the side with the steeper slope when warranted. If both slopes are relatively flat (illustration 3), place a median barrier (any type with dynamic deflection not greater than half median width) at or near the center of the median if vehicle override is not likely.

Section II. If the embankment slope is steeper than 1:10 but traversable (illustration 4), place a median barrier near the shoulder on the high side of the slope. If the slope is not traversable (such as a rough rock cut, illustration 5), place a roadside barrier at the top and bottom of the slope. If a retaining wall is located at the bottom of the slope, contour the base of the wall to the exterior shape of a concrete safety shape. If the slope is flatter than 1:10 (illustration 6), place a median barrier near the center.

Section III. If the median is sufficiently high and wide (illustration 7), vehicles may be redirected without a barrier. If the slopes are relatively flat and traversable, place a semirigid median barrier at the apex. If the slopes are not traversable, place a roadside barrier on either side.

When a median barrier is warranted, it is best to use the same barrier throughout the length of need. In cases where a roadside barrier is required on both sides of the median

PLACEMENT OF BARRIERS ON SLOPED MEDIANS

FIGURE 6.33 Tall-wall concrete safety-shape (unreinforced) median barrier. Conversion: 1 in = 25.4 mm. (From Roadside Design Guide, AASHTO, Washington, D. C., 2002 and 2006, with permission)

for some length and a centrally located median barrier is situated upstream and downstream, use a gradual transition between the systems proceeding in the direction of traffic.

Considerations

Posted by admin on 20/ 11/ 15

Different forces affect buildings in the various parts of the country. Builders have to worry about earthquakes in California, high winds in Florida, and snow loads in Colorado. It’s easier to understand the architect’s or engineer’s plans if you are aware of these factors. The following maps give you an idea of some of the areas of the country that suffer most from the effects of earthquakes, winds, and snow loads.

framing Details

The most common framing details can be broken down into three categories.

• Shear wall construction

• Diaphragm construction

• Connections

Each of these categories is covered in this section, including important points for framing.

Shear Wall Construction

The factors that affect the strength of any shear wall are:

• The size and type of material used for the plates and studs.

• The size and type of material used for the sheathing.

• Whether one side or both sides have sheathing.

• The nail sizes and patterns.

• Whether or not there is blocking for all the edges of the sheathing.

Engineers and architects are free to use any system they prefer, as long as they can prove that it meets the minimum strength requirements. The easiest and most common method is using the code book tables that provide accepted values for walls with

Seismic Map of Continental U. S.

given resistance capabilities. (Table 2306.3 in the 2009 International Building Code (IBC) shows these values.)

If there are many shear walls in a building, the engineer usually creates a schedule from a code table to show the wall requirements. Unfortunately, there is no standard for labeling shear walls, so the schedules made by the engineers may all be different. They do, however, usually have common
components. You will need to study the shear wall schedule on the plans to understand all the components that apply to framing.

Refer to the Shear Wall Schedule table later in this chapter for an example. It is an easy one to use because the labels also identify the nailing pattern and the type of sheathing. It was developed by the framing council in the state of Washington.

Important Points for Shear Wall Framing

1. Stud sizes—Specified nailing patterns may require changes in the stud sizes. There are three conditions where 3x studs are required for nailing adjoining sheathing edges. A fourth condition is required in seismic design category D, E, or F.

• If the edge nailing is 2%" O. C. or less.

• If there is sheathing on both sides of the wall, the adjoining sheathing edges fall on the same stud on both sides of the wall, and the nailing pattern is less than 6” O. C.

• If 10d (3” x 0.148”) nails are used with more than Ш” penetration, and they are spaced 3” or less O. C.

• (For seismic design categories D, E, or F) where shear design values exceed 350 pounds per linear foot.

2. Penetration—It is very important that the nail does not penetrate the outside veneer of the sheathing (see “Nail Penetration" illustration.) A pressure regulator or nail-depth gage can be used to make sure this doesn’t happen. (See “Nail Regulator and Flush Nailer" illustration.) The top of the nail should be flush with the surface of the sheathing.

3. Nail size—The nail size may change from wall to wall. Check the specified thickness and length of the nails.

4. Nail spacing—The pattern for nailing the sheathing to the intermediate framing members is usually the standard 12” on center. It is the edge nailing that changes to increase the strength. If 3x studs are required, then the pattern must be staggered. Make sure that the nails are at least 3/8” away from the edge of the sheathing.

5. Blocking—The details or shear wall schedule should specify whether blocking is required for panel edges. If the wall is 8′ or less, you can usually satisfy this requirement by running the plywood vertically, so that all the panel edges have backing.

Diaphragm Construction

The strength of diaphragms is affected by

these factors:

• The size and type of material used for the joists or rafters

• The size and type of material used for the sheathing

• The direction of the sheathing in relation to the members it is attached to

• The nail sizes and patterns

• Any blocks, bridging, or stiffeners

Nail depth gage

Nail regulator and flush nailer shown affixed to a pneumatic nailer

Nailing pattern for shear walls utilizing 3x studs

Building codes provide tables for diaphragms similar to those for shear walls. To summarize, the variables used to increase the strength of the diaphragm are the thickness of the sheathing, the size of the nails, the width of the framing member, the nail spacing, and whether or not the diaphragm is blocked.

Frost and Thawing of Pavements with Frost Susceptible Soils

Posted by admin on 20/ 11/ 15

8.3.1 Frost Heave — Introduction

Frost heave occurs in roads having fine graded, so called frost susceptible material, at a depth to which the freezing front reaches during the winter. The frost heave typically causes an uneven road surface and results in reduced travelling speed and comfort. The main problem though usually arises upon thawing when ice lenses involved with the frost heave melt and result in high water content in the pavement. The increased water content often means reduced bearing capacity and spring-thaw load restrictions are imposed to avoid severe pavement deterioration.

Granular pavement layers normally show a substantial decrease in stiffness with increasing values of moisture. Once thawing commences in the spring season, the granular layers often reach a state of near-saturation that substantially reduces the load carrying capacity. During the winter, short thawing periods have similar effect, especially on granular base courses. Therefore, seasonal changes cause a significant variation in the ability of a pavement to support traffic loads. During the thawing

period, water is melted from the ice lenses and since the layers where the ice lenses are formed have high fines content, the stiffness can drop dramatically. Since the road thaws primarily from the surface downwards, the free water can not drain through the still frozen underlying layers. Another effect of frost heave is that the road layer where the ice lens was formed loses its compaction (density) which is gradually regained under traffic load.

Determination of frost-sensitivity of soils is generally carried out using frost heave tests, such tests are mainly used to classify soils, according to their frost – sensitivity. However, prediction of the mechanical behaviour of such soils in pavements (heave during the frost period or loss of bearing capacity during thawing) is much more complex, because it depends on the climatic and moisture conditions, and on the characteristics of the whole pavement structure.

The principal characteristic of stiffness variation due to environmental effects is given in Fig. 8.7. During winter short thawing periods can cause temporary decreases in the aggregate base and sub-base stiffness. If the thawing penetrates down to the subgrade it also loses its stiffness. As the freezing starts again both layers regain stiffness. During spring thaw, the stiffness of the granular base and sub-base again lowers but the bearing capacity regains soon after the spring thaw period is over. However, if the subgrade has high fines content, it can take longer for the bearing capacity to recover.

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Considerations

Frost and Thawing of Pavements with Frost Susceptible Soils