Category A HOUSE

Keep your wits about you and pay extra attention to what you’re doing when you’re up on a roof—both to keep yourself safe and to ensure that the integrity of the roof is not compromised. To get on and off the roof, use a good, sturdy ladder that extends 3 ft. above the edge of the roof.

■ Keep the roof clean so that there won’t be anything to trip over.

■ Be careful when sawdust is on the roof. Sawdust on a sloped roof can be as slick as ice. To be safe, call out measurements to cutters on the ground and have them clear the board of sawdust before handing it up to you.

■ Never throw anything off a roof, not even a shingle, without first checking to see that no one is down below.

■ In the hot sun, asphalt shingles soften and tear.

Walk gently so you don’t damage the shingles. In hot weather, install shingles early in the morning or late in the afternoon.

■ In bitter cold weather, shingles become brittle and crack. Work carefully, and pray for sunshine.

■ Shinglers who nail off a roof by hand often sit on the roof as they work. In hot weather, try sitting on a piece of foam while nailing shingles. Otherwise, hot shin­gles can literally burn your backside.

Unless the trusses were set on the walls at the time of delivery, they must be hoisted onto the walls by hand (see the photo on the facing page). One way to do this is to set good, strong ladders at both corners of the building. If you’re dealing with long trusses, place a 2x in the center, from the ground to the top plate, at the same angle as the ladders. This way, two people can lift a truss, lay it against the ladders and the center 2x, and walk it up to the top. Another person in the middle with a notched pole can push on the truss as needed.

In preparation for installing the first truss (the gable-end truss), I nail a long, straight, tem­porary 2x brace on edge to the wall frame near the center of the end wall. This holds the gable – end truss stable until other braces are installed.

If the truss is not too large, one person on top can drag the truss to the opposite end and lift it up against the temporary brace. Make sure that the eave overhangs are correct and that the out­side of the bottom chord is flush with the outside of the end wall’s top plate. Toenail the bottom chord to the double top plate, driving 16d nails every 16 in.

Trusses take team­work. A crew of four does a good job of getting roof trusses up on the walls. Us­ing a long push stick, the ground worker helps elevate the truss.

The temporary catwalk allows you to take a truss from a bundle and move it across the walls. Pull each truss, peak first, and spread it out near its layout mark. Each truss overlaps the previous one like a fallen domino.

STEP 2 INSTALL THE GABLE TRUSS

The first truss to be installed is the gable truss (also called an end truss or a rake truss) that rests on the top plate of an end wall. This truss is usually built differently from regular trusses. Instead of having angled web pieces, these end

Rolling roof trusses. The first truss you should nail in place is the one for the gable end. Then it’s just a matter of rolling the remaining trusses in place, setting them on their layout marks, and nailing them down. You can do this while standing on the walls or by working off a ladder. [Photo by Don Charles Blom, courtesy Fine Homebuild­ing magazine © The Taunton Press, Inc.]

trusses often have vertical webbing spaced 16 in. or 24 in. o. c. to allow for easy installation of sheathing or siding.

Some carpenters like to sheathe end trusses with OSB and even finish siding before raising them upright. Another option is to cut all the sheathing pieces on the ground, raise the truss, and then nail the precut sheathing in place. It is certainly easier to sheathe a truss on the ground, but it makes the truss substantially heavier and more difficult, even dangerous, to handle. If you do decide to sheathe the trusses before raising them, let the sheathing lap down below the ceiling joist chord by a couple of inches. The lap will be nailed to the top plates once the gable is raised upright. This helps ensure a strong union between the truss and the wall, which is especially important in windy areas.

Notch the gable-end truss

Notches for lookouts are exceptions to the “never cut a truss” rule. Lookouts hold the barge rafters, which extend beyond the building line at each gable end to create a roof overhang (see the photos at right). Gable trusses are not self-supporting. They can be notched because they are nailed directly over a load-bearing wall. As a result, the entire joist chord of each a gable-end truss is fully supported.

It’s best to cut notches for 2×4 lookouts while the gable truss is still lying flat. For the first lookout, measure and mark 48 in. from the end of the truss tail. Cut a 2×4 notch (which is actu­ally ІУ2 in. deep and ЗУ2 in. wide) below the first 48-in. mark and every 48 in. thereafter (see the illustration on p. 121). With the gutter board or fascia in place, 4-ft.-wide sheathing will fall on the lookouts.

CHOOSING NOT TO NOTCH. Some houses (especially in northern areas) are designed without gable-end overhangs so that more sunlight can get into the house. If this is how you plan to build a house, lookouts or notches are not necessary. Instead, furr out the rake board with 1 x lumber, so that the exterior siding tucks under it (see the illustration on p. 120).

In the dry Southwest, open, exposed rafter tails are preferred. But elsewhere—especially in cold, wet locations—soffits are more popular. Eave soffits are usually vented.

There are quite a few ways to frame soffits. The easiest way is to have the truss company extend the joist chord beyond the building line to form a level overhang. This is called a raised-heel truss.

If the trusses do not have a raised heel, you can still build a sof­fit easily by sheathing the underside of the sloped rafter tails. For a level soffit, nail a long 2x to the building and sheath between it and the gutter board or subfascia. If only a fascia board is used, cut a groove near the bottom edge to support the outer edge of the soffit board. No matter which type of fascia treatment you choose, make sure you install fire-stops between the studs to help prevent a fire in the wall from spreading into the soffit area. Check with your building department to find out which fire-stop details are required.

exterior walls and mark the entire length of the building at 2 ft., 4 ft., 6 ft., and so on, putting an “X” on the far side of each mark. Do the same on any long interior walls that run parallel to the outside walls. Mark the same 2-ft. o. c. layout on several straight 16-ft. 1×4 boards. These 1xs will later be nailed near the ridge to hold each truss upright at the proper spacing. Despite your best efforts to line the walls (as explained in Chapter 4), the exterior eave wall plates may not be totally straight. If you hold the truss overhang to a wall that is not straight, the rafter ends and fascia won’t be straight, either. There is an easy way to remedy this. Measure 1 in. in from the outside at each end of the exterior wall’s top plate. Snap a chalkline the full length of the wall to create a straight reference line. Make an alignment mark on the joist chord of each truss. Measure in from the end of the truss the planned eave overhang distance plus 1 in. When install­ing each truss, put the truss mark right on the plate’s snapped reference line. As long as the truss fabricators cut all the tails the same length, the truss ends will be aligned.
WITH A RAISED-HEEL TRUSS
-Roof sheathing	With a raised-heel truss, th e joist chords provide the framing for the eave soffit.
Rafter chord
Fascia Soffit vent
Joist chord Exterior wall —
Soffit sheathing
Wall sheathing WITHOUT A RAISED-HEEL TRUSS
Subfascia
A groove in the fasciai supports soffit board.
2x – nailer
Fire-stop

be open or closed. For details on different ways to finish off an eave, see the sidebar on p. 117. NUMBER OF TRUSSES. Roof trusses are typically spaced 24 in. o. c. Therefore, if your building is 40 ft. long, you’ll need to order 21 trusses. Two of the trusses will be for the gable ends. These trusses have studs rather than webbing to receive the exterior wall covering. SPECIAL REQUIREMENTS. If your house has a more complex roof, special trusses may be required where one roof section joins another. Often houses are built in a “T” or “L” shape or have a side porch that connects to the main roof. You can cut the rafters needed to tie the porch roof to the main roof. Another option is to have the truss builder look at the plans, check the span of these trusses, and build to your specifications.

ROOF PITCH. Trusses for most small affordable buildings have either a 4-in-12 or a 5-in-12 pitch (see the illustration on the facing page).

STEP 1 PREPARE FOR TRUSS ARRIVAL AND INSTALLATION

When roof trusses are delivered to a job site, they can be offloaded onto the ground or onto the framed walls of the building (see the photo on p. 115). The choice depends on the builder’s preference and on the delivery truck’s capabili­ties. Experienced builders prefer delivery on the walls because it saves time. Trusses can be long and cumbersome. Putting them up on walls by hand can be difficult, dangerous, and time consuming. Most truss builders deliver the trusses on a boom truck. The boom can be used to set all the trusses directly on the walls. Plan ahead and order truss delivery the day after all the walls are framed and braced.

Whether your trusses are offloaded onto the walls or onto the ground, they need to lie flat.

I have seen trusses that were stored on uneven ground come apart at the seams, making them useless within a couple of weeks. Until they are nailed upright in place, braced, and sheathed, trusses are actually quite fragile. Prepare a flat area close to the house where the trusses can be offloaded. The bottom-most truss should not rest directly on the ground but on wood stickers that provide a flat, level base.

Set up work platforms

One of the most difficult parts of roof-truss installation is working high off the ground. It takes skill and practice to be able to stand on a narrow top plate and nail trusses to the wall. If this seems dangerous, or if you’re uncomfortable with it, try working on a ladder or a scaffold instead. To make it easy to move trusses into position, I like to build a catwalk, or walkway, over open sections, such as the living room. (For directions on how to erect a catwalk, see the illustration on p. 118.)

Mark truss locations

Before trusses arrive on the job site, take some time to lay out their locations on the top of the wall plates. Hook a long tape on the end of the

A Roof Overhead

The walls for our house are up and we now have something to show for our work. At this stage, we can walk through the structure; admire the view through rough window openings; and imagine how the finished siding, painted drywall, and flooring will look. But first, we need to raise the roof.

Before we reach for a hammer, we need to make some decisions about the roof trusses. We also have to prepare the site for their delivery and do some layout work so that the installation process can go smoothly. Once the trusses are installed, we’ll move on to the fascia boards, sheathing, and shingling.

Roof Trusses

Early in my building career, I was taught how to lay out rafters with a site-made template containing the plumb and bird’s-mouth cuts. You can still cut and frame a roof one rafter at a time (see the illustration on p. 114), but today most roofs are constructed with factory-made trusses. Trusses are designed on a computer, built on an assembly line, and delivered to the job site ready to install. If you’re building a simple gable-roof house like the one shown here, roof trusses can save time and keep the construction process simple—something that everyone will appreciate.

Each truss includes a pair of rafters and a bottom chord that functions as a ceiling joist inside the house and as level soffit framing outside the house. Short lengths of wood, called webbing, connect the rafters with the bottom chord; barbed steel gusset plates (gussets, for short) are pressed into place over the joints to hold all the parts together. For a basic look at the different truss configura­tions, see the illustrations on p. 115. The basic roof installation process that we’ll use on this house will be very much the same for other houses, regardless of size.

Porch considerations

On the house we’re building, the main roof extends over a small porch. In this situation, you need to have at least some of the porch framed before installing the roof trusses. Some builders choose to erect temporary posts to support the top beams on which the roof trusses (or rafters) will bear. When the porch is completed later, these temporary posts are replaced with per­manent ones. This strategy allows roof framing to follow wall framing directly, without the interruption of porch construction work. For details on how to build a porch or a deck that’s attached to the house, see Chapter 7.

Ordering roof trusses

After you make a few basic decisions about the trusses for your house, it’s fairly easy to order them. I like the raised-heel design of the trusses we used on this house (see the top illus­tration on the facing page). This type of truss
provides an overhang along the eave walls as well as framing for a level soffit. Because the rafter is elevated above the wall’s top plate, there’s ample room for ceiling insulation and ventilation space above.

However, as shown in the illustration on the facing page, other truss designs are also possible. Depending on your budget and design prefer­ences, you can use a scissor-type truss and have a cathedral ceiling inside the house. Or perhaps you like the rustic appearance of an open soffit and exposed rafter tails along the eaves. A good lumber dealer has different truss designs to show you, and it’s worth taking a look. Once you decide, here are the basic specifications the manufacturer needs to design and construct your trusses:

TYPE OF TRUSS. The major types of trusses for gable roofs are shown in the illustrations on the facing page.

SPAN BETWEEN EXTERIOR WALLS. The

span is measured from one outside edge of the building to the other.

EAVE DETAILS. The amount of overhang at a building’s eaves is usually shown on the plans. The plans should also tell you whether the soffit will

There are many areas in the country where ply­wood or OSB sheathing is required only at exte­rior corners and every 25 ft. along exterior walls. This allows you to install nonstructural sheathing material everywhere else. On this house, we used /fi-in. foam sheathing. The foam board is light and easy to handle, though it can be damaged by a stray hammer blow or by someone stepping on it. Attach foam sheathing with l’/Tin. roofing nails. Sheathe right over window openings, then go inside the house with a handsaw and cut out the foam from the openings (see the right photo on p. 109).

If you’ve come this far, congratulations!

Make sure you spend some time cleaning up the job site at this point in your project. There are bound to be plenty of offcuts, such as 2x stock, plywood or OSB scraps, and stray fragments of foam sheathing. Remove the debris and get set to raise the roof.

I lived through the 6.8-magnitude earthquake that hit Northridge, California, in 1992. It made me believe in wall sheathing. A 6.8 quake is not a big one, yet a number of people lost their lives. More lives would have been lost if critical areas in buildings had not been sheathed with ply­wood or OSB. The buildings that held up best were small, single-story wood-frame houses, such as those built by Habitat. Many were knocked several feet from their foundation, but they didn’t collapse on their occupants.

Unlike drywall, stucco, and most exte­rior siding, plywood and OSB wall sheathing provide both lateral (horizontal) and verti­cal strength. Sheathing helps hold buildings together and makes a house windproof, which is important if you live in an area where cold winds are a reality.

Because sheathing panels will be covered with finished siding, they don’t need to be installed perfectly. Earthquake – and hurricane – country sheathing codes are often quite strict, so check with your local building department before you start covering walls. Again, remem­ber to insulate corners, channels, headers, and behind tubs before you attach wall sheathing.

Install sheathing on the corners first

I always install sheathing on the corners first (see the left photo on p. 109). To hold a sheet in position while you get ready to nail it, try driv­ing a couple of 16d nails near the bottom of the wall. Keep plywood and OSB in. away from a masonry foundation. If the stud layout is cor­rect, the edge of the first panel should fall on a stud 4 ft. from the corner. In humid areas, leave a //8-in. expansion gap between sheets. If a sheet
doesn’t break on the center of a stud, rip the sheet to fit, move the wall stud, or put in an extra stud.

You can sheathe right over windows and doors and cut them out later with a reciprocat­ing saw. Use scrap pieces to fill in gable ends and underneath windows or to cover rim joists.

I also sheathe various walls inside the house, though this goes beyond most codes. I do this because I know that a few extra sheets of OSB might save someone’s life during an earthquake or a tornado. Sheathing the back wall of a closet, bathroom, or utility room gives the frame extra lateral stability. In areas prone to serious torna­does, you may be required to create an entirely sheathed and well-anchored safety room in which household members can gather during a storm.

The nailing schedule lor sheathed walls often requires 8d or 10d nails at 4-6-12. This means that nails are spaced 4 in. around the perimeters of walls, 6 in. at the joints between sheathing panels, and 12 in. in the field. Check with your building department for the required nailing schedule in your area.

Many builders—even experienced ones—don’t like to spend time plumbing window and door trimmers. But I’ve found that this step really makes a better building. If the door trimmers are plumb, the door’s hinge-side jamb butts solidly against the trimmer along its entire length. There’s no need for shims on this side of the door. That means you save time and obtain solid, continuous backing for the jamb that sup­ports the full weight of the door. If the opposite trimmer is also plumb, the shims you install can
share the same thickness. There’s no fussing to make shims of different sizes. Similarly, win­dow installation benefits from plumb trimmers.

Window trimmers were installed during step 5, when the window assemblies were built on the floor deck. Full-length window trimmers are firmly attached at the bottom corners of the rough window opening, but each trimmer can still be pried away from its king stud to get the trimmer as plumb and straight as possible. Use a straight claw on a framing hammer or a flat bar to pry and a 2-ft. level to test for plumb and straight. When the trimmer is where you want it to be, secure it by toenailing through the header

SHEATHING A WALL

When all the walls have been raised, braced, and lined, it’s time to attach the sheathing. On this house, two types of sheathing are used. To provide shear bracing, OSB panels are installed on all corners and every 25 ft. along exterior walls. Foam-board sheathing is nailed to the framing between wood panels. It’s easier to sheathe right over window and door openings, then cut out the openings from the inside. Foam cuts easily with a handsaw.

with 8d nails. Make sure you toenail from both sides of the wall. To lock a trimmer in straight position, hammer a nail clip into each edge of the trimmer, as shown in the illustration on p. 108.

It’s best not to install door trimmers until af­ter the walls have been raised and braced. This way, each trimmer can be measured and cut to fit snugly up against the bottom of the header.

I carry two straight studs to each opening, hold them in position under the header, and mark them to length. When the trimmer has been cut for a snug fit, secure it to the king stud with a single 16d nail driven near the center. Don’t drive any more nails, because you will need to tap the 2 x in or pry it out slightly to get it plumb. Test for plumb with a 6-ft. level. When it is plumb, drive toenails through the header and into the trimmer, then toenail the trimmer to the bottom plate.

Finish by getting the trimmer straight, using nail clips, if necessary. When the sheathing is installed, you can lock the trimmers in place by nailing through the sheathing and into the trimmers’ edges.

To plumb walls, you can make a plumb stick from any 2-ft. level and a straight 2×4 stud. Even a battered, inaccurate level can be used. Select the straightest stud you can find and nail a 16-in. 1×2 strip onto each end, letting the strips overhang the stud ends by about 3 in. Use some duct tape to attach a 2-ft. level to the op­posite edge of the 2×4 (near the center) and your plumb stick is nearly ready to use (see the photo below).

It’s important to check your plumb stick for accuracy. To do so, hold it vertical and flat against a wall. Keep the bottom end fixed in place as you move the top end back and forth until the bubble is exactly centered in the vial. Make pencil marks on the top and bot­tom of the wall along the 1x extensions. Now turn the plumb stick side for side—not end for end—so that the level is flat against the wall on the other side of the lines you marked. Carefully line up the extensions with the marks on the plates. If the bubble returns to the exact center of the vial, the plumb stick is accurate. (By the way, you can check the accuracy of any level with this method.)

If the bubble is not centered in the tube, the level needs to be adjusted. Stick a wooden shim, a folded piece of paper, or an 8d nail under one end of the level (between the level and the 2×4), and then check the plumb stick again. Keep adjusting the shim thickness un­til the bubble is centered both ways.

1.
Once the trimmer is plumb, drive an 8d nail into the edge partway and then bend it over, embedding the shank and head in the king stud.

2. Clip the first nail by bending a second nail over it. Hammer the clip until both nails are fully em­bedded in the wood.

This pair of 8d nails clips one piece of wood next to another. Pairs of nails are frequently used to clip a trimmer stud plumb next to a king stud.

move the top plate out until it’s straight, then secure the bottom of the brace to the floor with two 16d nails. If you are framing on a slab, first nail a 4-ft. 2x flat on the bottom plate at a right angle to the wall, then nail a brace to the wall and to the flat 2x.

Moving a wall in is a little trickier. Try this: Nail a long 1x or 2x under the top plate and against the subfloor. Then place a short 2x un­der the center of this diagonal brace and bend the brace upward. As the brace flexes upward, the top plate moves in. This works especially well on a wall that is badly out of line.

Make sure you use enough temporary braces as you plumb and straighten the walls to keep every wall in place. Put braces on straight walls as well. Using plenty of braces ensures that the building will be held plumb and straight. Leave all the braces in place until the roof trusses and sheathing have been installed to prevent any frame movement.

Hold a level or plumb stick in a corner to see whether the bubble is centered in the vial. If not, the wall must be moved laterally. Sometimes a wall can be moved a bit with a bodily shove. If you can push the wall plumb, install a temporary 2x diagonal brace to keep it that way (see the photo above). If you need
more force, use a push stick, as shown in the top photo on the facing page. Cut a push stick from a 1×4 or 1×6, making it about 116 in. long for an 8 ft. wall. Use the natural flex in the push stick to exert force on the wall. Position the top of the stick under the top plate and against a stud. Diagonally extend the stick down to the floor, as parallel as possible to the wall. Bend the stick down, holding the bottom end against the floor with one foot. Now pull the middle of the stick up. As the board straightens, the wall moves.

After the wall is plumb, finish nailing in the metal braces or use temporary 2x stud braces nailed at an angle to hold the wall plumb until it is sheathed. When the exterior walls are plumb, proceed to the interior walls. You can’t straighten a wall until the walls that butt into it have been plumbed.