Blog Archives

Framing According to Code

Posted by on 20/ 11/ 15

Floor Framing

Following are the code requirements and instructions related to floor framing:

• Double joists are required under parallel bearing walls.

• If pipes penetrate floors where double joists are required, the joists must be separated and have full-depth, solid blocks at least every 4′ along their length.

• Bearing for joists must be Ш" minimum on wood or steel, and 3" minimum on concrete or masonry.

• Where joists lap, there must be a minimum lap of 3" or a wood or metal splice of equal strength.

• The ends of joists must be kept from turning by using Ш" full-depth solid blocking or by attaching them to a header, band, rim joist, or adjoining stud.

• Full-depth, solid blocking is required at intermediate supports in IRC seismic design categories D1, D2, and E...

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BUILDING CODE REQUIREMENTS

Posted by on 20/ 11/ 15

Framers, builders, architects, engineers, and building inspectors alike have contributed to the system of building codes we use today. You should be aware of the codes that apply to the part of the country you are working in, as well as the important features of those codes. This chapter will discuss what you should know about building code requirements.

Introduction to Building Codes

The Evolution of Building Codes

Although carpentry is one of the oldest professions, framing as we know it today didn’t start until 1832 when a man named George Snow wanted to build a warehouse in Chicago. It was difficult to obtain enough large timbers to build the structure using the traditional post and beam method...

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Flash the ledger

Posted by on 20/ 11/ 15

Many builders like to use flashing when installing a ledger. Find out which types of flashing builders use in your area. I tend to use heavy-gauge aluminum behind the ledger, though I sometimes opt for high-quality galva­nized sheet metal or even copper—expensive though it is—instead of aluminum. Although it can take a while, ocean air and city smog will gradually take their toll on aluminum flashing, causing it to deteriorate.

The flashing is installed before the exterior siding. It can be nailed directly to the wall framing and rim joist if no sheathing has been used on the exterior walls. Otherwise, install the flashing on top of the wall sheathing (see the illustration at left)...

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Generating multivariate random variates with known marginal pdfs and correlations

Posted by on 20/ 11/ 15

In many practical hydrosystems engineering problems, random variables often are statistically and physically dependent. Furthermore, distribution types for the random variables involved can be a mixture of different distributions, of which the corresponding joint PDF or CDF is difficult to establish. As a practical alternative, to replicate such systems properly, the Monte Carlo simulation should be able to preserve the correlation relationships among the stochastic variables and their marginal distributions.

In a multivariate setting, the joint PDF represents the complete information describing the probabilistic structures of the random variables involved...

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Generating multivariate normal random variates

Posted by on 20/ 11/ 15

A random vector X = (X1, X2,…, XK)t has a multivariate normal distribution with a mean vector fj, x and covariance matrix Cx, denoted as X ~ N(px, Cx). The joint PDF of K normal random variables is given in Eq. (2.112). To gener­ate high-dimensional multivariate normal random variates with specified (j, x

Generating multivariate normal random variates

Drawdown recess time (days)

Figure 6.4 Histogram of simulated drawdown recess time for Exam­ple 6.4.

and Cx, the CDF-inverse algorithm described in Sec. 6.5.1 might not be efficient. In this section, two alternative algorithms for generating multivariate normal random variates are described. Both algorithms are based on orthogonal trans­formation using the covariance matrix Cx or correlation matrix Rx described in Sec. 2.7.1...

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POST-AND-BEAM SUPPORT FOR A PORCH ROOF

Posted by on 20/ 11/ 15

Подпись: Porch beam sets into notch in wall.Подпись: ^ Rim joistПодпись: Metal post baseПодпись: Concrete pierПодпись: Porch beams are level with the top of the top plate and are attached to the house frame with metal tie straps.POST-AND-BEAM SUPPORT FOR A PORCH ROOFПодпись: XPOST-AND-BEAM SUPPORT FOR A PORCH ROOF

Подпись: FRAMING CONNECTORS ARE ESSENTIAL. Steel connecting hardware is required when building a porch or a deck. A post cap connector (see the photo far left) is useful for strengthening the joint between a porch post and a roof beam. A post base (see the photo near left) is mounted on a concrete pier; it has holes for lag bolts, which fasten it to the post. [Photo far left ~ Larry Haun; photo near left ® Memo Jasso/Brown Studio.]

Helping Hand

Framing connectors are worth checking out. If you haven’t discovered the vast variety of framing connec­tors that are available, try to do so before building a porch or a deck. A well – stocked lumberyard or building supplier will sell connecting hardware designed to reinforce all kinds of joints among dif­ferent framing members.

POST-AND-BEAM SUPPORT FOR A PORCH ROOFSTEP 2 Install the Ledger

On a house built over a basement or crawl – space, a deck or porch can be attached to the house frame. Deck building then becomes a lot like framing a floor-joist system inside a house (see chapter 3). Step one in this process is to attach a ledger to the house frame. Straight, level, and solidly secured to the house, the ledger acts like a rim joist for the porch...

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Influence of Surrounding Terrain on Proper Breakaway Performance

Posted by on 20/ 11/ 15

Breakaway supports are designed and evaluated to operate safely on the basis of the char­acteristics of the vehicle fleet. One of the primary characteristics included in discussions of the impacting vehicle is its weight. While weight is very important, the bumper height is equally important, since it establishes where the vehicle weight is first concentrated on the breakaway support. The majority of the safety evaluation tests are conducted on level terrain. This implies that the impacting design vehicles are striking the breakaway supports at a known height—typically, about 20 in (500 mm) above the ground. Roadside safety could, therefore, be enhanced if wide, level areas are provided along the roadside.

Providing this level roadside is not practical or possible in the majority of roa...

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Basic Design for Porches, Decks, and Landings

Posted by on 20/ 11/ 15

THE PORCHES ON HABITAT HOUSES ARE AMONG THEIR NICEST FEATURES. AH

Habitat houses have a covered porch of some sort. On the Charlotte house, there’s a small porch tucked underneath the main roof, sheltering the main entry door. The side door has a landing that could grow into a larger deck sometime in the future (see the photo on the facing page). Most of the Habitat houses I’ve worked on out West have a porch as an attached structure. It has its own roof, which joins either the main roof or the gable end of the house (see the photo on p. 176). In almost any form, a porch adds something special to a house. Its a place to put some flowers, kick off your shoes when you get home from work, or just sit down and relax at any time of day.

I have built hundreds of decks and porches over...

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LONGITUDINAL FAT SPOTS OF MASTIC (SEGREGATION)

Posted by on 20/ 11/ 15

Mastic fat spots may be distinguished from binder fat spots using a tool to check the composition of a particular fat spot. All the elements that make mastic—binder, filler, fibers and sand—can usually be identified in a cross section of a fat spot. It is neces­sary to examine what is going on around the fat spot to discover its cause. Usually there is one of two sets of conditions—with segregation or without segregation.

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Roof

Posted by on 20/ 11/ 15

Подпись:RoofRoof

The roof is the part of the wood-frame structure that varies most widely across the country. This is because the roof plays the most active role of all the parts of a building in protecting against the weather, and in the United States, variations in weather are extreme. Some roofs protect primarily against the heat of the sun; others must shelter the inhabitants under tons of snow.

SELECTION OF ROOF SLOPE

One of the most obvious variations of roof form has to do with the slope or pitch of the roof. The main factors affecting the slope of a roof are stylistic considerations, the type of roofing material to be used, and the space desired beneath the roof. The climate also has a strong influence on roof slope...

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