Category A HOUSE

The vent pipes that extend through the roof are flashed with special rubber or metal boots when the shingles are installed. But here in rainy Oregon, roofers take the time to make a double seal around these pipes. This is sort of like wearing a slicker and carrying an um­brella, too—but there’s no such thing as being too careful when it comes to roofs and water.

To provide this extra protection, cut a 3-ft.-sq. piece of felt and cut a hole in the center the size of the vent pipe. Slip the felt over the vent and seal around the pipe with a tube of roofing tar. Do the same when you roll out the long strips of roofing felt. Cut the second layer of felt around each vent and again seal it around the pipe with roofing tar. You can lap the felt over the ridge, but remember to cut it away when you shingle to permit airflow into the ridge vent.

Protect valleys and intersections

When a porch roof intersects the main roof at a right angle, valleys are created on each side of

the intersection. Valleys divert more water than a regular gable roof does, so I always provide extra protection in the form of flashing. I like to roll at least two layers of 30-lb. felt right down the center of the valley. Even better is to cover the valley area with a sheet of 90-lb. rolled roof­ing. Then, when you install regular roofing felt, lay each row 12 in. or more beyond the valley and keep all roofing tacks at least 12 in. from the center of the valley. This technique provides a double layer of protection prior to shingling.

When working on a roof that butts into the sidewall of a house (a porch roof connected to a gable end, for example), lap the felt on the sidewall by at least 6 in. to prevent leaks at the intersection.

Install a drip edge

Once the felt is in place, make it more secure around the edges by installing sections of vinyl or metal drip edge. Drip edge is an L-shaped metal or vinyl flashing that comes in 10-ft. sections. One leg of the L profile extends about ІУ2 in. up the roof; the other leg extends down the fascia or barge rafter by the same distance (see the photo at right). It has a slight lip on the lower edge to divert water from the roof.

Using roofing nails, install the drip edge under the felt at the eaves and on top of the felt at the rakes, or gable ends. Space nails about 2 ft. apart. Where one length of edging joins another, overlap the joint by about 4 in. Along the gable ends, make sure the top length of the drip edge laps over the one below. At the corners, cut a pie-shaped slice out of the top section. This allows you to bend the drip edge at a 90-degree angle and nail it around the corner. At the ridge, make a plumb cut in the vertical leg and bend the edge over the ridge, allowing the plumb cut to overlap, as shown in the illustration above.

Installing a drip edge. This L-profile flashing is installed to protect the edges of the roof. The bot­tom flashing goes beneath the paper and the side flashings go on top. [Photo by Don Charles Blom]

STEP 9 SHINGLE THE ROOF

Now that the house has been framed and sheathed, it’s time to seal it from the elements. As long as you are able to work safely on a roof, you can cover it with roofing felt and shingles. It’s best if all the plumbing and heating vents are through the roof before you install the felt.

If that isn’t possible, just make sure they’re installed before you begin shingling.

Roll out the felt paper

Felt paper, sometimes called tar paper or builder’s felt, is the first protective layer installed over roof sheathing. This material has evolved in a fashion similar to that of a candy bar. In the

old days, you could buy a good-size candy bar for a nickel. Today, you get a much smaller bar at a higher price. Similarly, the felt paper avail­able today is much lighter, even though it’s still sold as 15-lb. and 30-lb. felt. I like to use 30-lb. felt for the underlayment because it provides extra protection and the cost difference isn’t that great. Roofing felt has horizontal lines marked on it. Follow a line that provides a minimum 4-in. lap as you roll one row over another.

Follow nailing guidelines

Some builders like to snap a chalkline on the sheathing 36 in. up from the edge of the gutter or fascia board and lay the first roll of felt to that line. This makes the roll lay down straight. Alternatively, you can hold the felt flush with the edge of the roof. Unroll the felt flat (with no bumps or wrinkles) and tack it down with roof­ing tacks. A roofing tack is a small nail with a large plastic button (generally green, orange, or red) on top (see the photo above). Or you can use a pneumatic nailgun to nail these plastic buttons in place. Stepping on felt that is not nailed well can cause you to slip off the roof, so use plenty of roofing tacks (6 in. o. c. at the
bottom and ends and 10 in. o. c. from top to bottom every 24 in. o. c. across the roof). Roofing tacks hold the felt in place, which is especially important if the roof won’t be shingled for several days. Pick up any tacks that fall to the ground so that no one steps on them. Finally, trim the felt flush with the gable ends.

Whether you are tacking down roofing felt or nailing on shingles, it’s important to consider whether the nails can be seen from below. When the eaves around the house are open (no soffit), a long nail penetrates the roof sheathing and is visible to anyone who looks up. Hundreds of shiny nails sticking through the plywood or OSB is unattractive. Therefore, when tacking felt around the perimeter of the roof, take care to nail the tacks into the barge rafters and gable-end rafters—not just through the sheathing into the air. When nailing shingles, use 5/s-in. nails at the gable overhangs and eaves. When working over the house frame, nails that penetrate the sheath­ing in the attic are not a problem.

Sheathing a roof is much like sheathing a floor, except that the deck is sloped, not flat, and you work at least 10 ft. off the ground. Anyone who has worked in the construction trades for more than a few years has heard stories about someone who has fallen from a roof—or has seen it happen. I was sheath­ing a roof many years ago on a cool morning with a bit of frost on the ground. The sunny side of the roof had no frost. Without think­ing, I stepped onto the shady side of the roof and was immediately careening down a fairly steep pitch, heading for doom. Fortunately, I had my straight-clawed hammer in my hand. Instinctively using it like an ice ax, I sunk the claw into the sheathing, stopping myself just short of the roof’s edge—a thrilling way to drive up my heart rate at the beginning of the day but not an experience I’d care to repeat. Take care, and stay aware.

MAKING A PLATFORM FOR ROOF SHEATHING

A safe strategy for hoisting sheathing onto a roof is to build a simple stag­ing platform, as shown in the photo at right. Nail the platform’s two hori­zontal supports (a pair of 2x4s works fine) to the wall framing or, if the wall has been sheathed already, to a 2x cleat nailed through the sheathing and into the studs. The supports must be a couple of feet above the bottom plate of the wall. Space them about 32 in. apart, and make them roughly level. Support the outboard end of the platform with 2x legs firmly attached to the horizontal supports. Nail a 2x on top of the platform near the outer end to provide additional stability. If necessary, install diagonal braces between the supports and the legs or the wall framing for added strength. Then set 4×8 sheets of plywood or OSB on edge on the platform; workers on the roof can grab the sheets as needed.

Measure 481/4 in. from the outside edge of the gutter or fascia board at each end of the roof and snap a chalkline. Lay the first row of plywood or OSB so that the top edge is right on this line (see the photo at left). Make sure the sheathing extends past the gable-end truss all the way to the barge rafter, which the sheath­ing helps support. Lay the slick side of the OSB down. Nail the sheets with 8d nails at 6 in. o. c. at the edges and 12 in. o. c. in the field. Be sure to nail all the boards.

Before you start the second row of sheath­ing, put plywood H-clips, centered between the rafter chords, on the first row (see the top photo on the facing page). Required on /’2-in. sheath­ing (but not on 5/8-in. sheathing), these clips hold two sheets together and make the roof’s surface stronger. Start the second row at one end with a 4-ft.-sq. sheet so that the courses will be stag­gered, just as they are with floor sheathing. Continue sheathing until you reach the top. If a ridge vent will be installed, leave a gap at the ridge so that air inside the attic can move up into the vent. If the vent is available, read the

manufacturer’s instructions regarding the size of the gap and check with your building inspec­tor regarding these construction details. The gap need not run all the way to the barge rafter. Start it about 1 ft. in on the main roof.

2. Then nail on a 1×2 fence.

If you need to make a series of plumb cuts to match and align rafter tails along an eave, make a jig like the one shown here. Use a rafter square to mark the plumb-cut angle of the roof (4-in-12 or 5-in-12) on a short length of 1×4 or 1×6, depending on the rafter size. Cut a parallelogram-shaped template with
identical plumb-cut angles, then nail a short 1×2 fence to the upper edge of the template. Once a chalkline has been snapped across all the rafter tails, use this template to mark the plumb cut on them so that they can be cut to length.

boards are less demanding. On this house, we installed gutter boards that were later clad with coil aluminum (see Chapter 7). CUTTING AND NAILING GUIDELINES FOR GUTTER AND FASCIA BOARDS.

Use long, straight stock for gutter or fascia boards. Both types must butt together over the solid backing of a rafter tail. Gutter boards can meet in a simple butt joint; fascia boards should meet with a mitered joint, as shown in the illustration at left.

Nail gutter and 2x fascia boards to truss or rafter ends with 16d, hot-dipped galva­nized nails. Nail fascia boards with a finish hammer, being careful not to miss the nail or you’ll leave hammer tracks in the wood. Have a partner hold the other end of the board. Hold the board down a bit on the rafter tail so that the roof sheathing just skims over it (see the illustration on the facing page). To line

up everything correctly, tack a piece of scrap wood on the top edge of a rafter and let it project downward, the way the roof sheathing will. Drive the topmost nail high enough so it will be covered by the drip edge that will be installed later.

At the bottom corner of the roof, the level eave trim meets the pitched barge rafter. If the exterior trim will be covered with cladding, as on this house, plumb-cut the barge rafter and nail it to the plumb-cut end of the gutter board. Install the gutter board so that it runs long, just like the lookout boards, then mark the correct overhang distance on the gutter board and on the topmost lookout. Be sure to take the barge rafter’s thickness into account. Snap a line between these two marks, then cut the gutter board and lookouts in place. Now you’re ready to cut and install the barge rafter.

The procedure is similar if you’re install­ing fascia instead of gutter boards; however, miter the end of the fascia board to fit a mitered plumb cut on the barge rafter (see the photo on p. 128). It’s easier to make both miter cuts before nailing the boards. Miter and install the fascia first, then snap the cutoff lines on the lookouts as described previously.

Plumb-cut barge rafters

Select straight, clear stock for the barge rafters, and start with a board that’s a little longer than you need. Make the bottom plumb cut on the ground. This is a mitered plumb cut, 4-in-12 on this roof, if you’re working with finished trim. With one or two helpers holding the board above, nail the barge rafter to the lookouts and to the gutter or fascia board. I like to make the top plumb cut with the board in place, judging by eye where the top of the cut should be. Or you can pull a string along the top of several trusses. Pull this string out over the barge rafter to mark where it will cut. When you install the opposite barge rafter, mark the top plumb cut against the rafter you’ve already cut to ensure a tight-fitting joint.

Code requires an access hole for the attic. This al­lows workers to get into the attic to install insulation and wiring. You may also want to get up there some day to check on a roof leak or just to see how the spi­ders are doing.

The standard attic access hole has a rough 2x frame that is 221/2 in. wide by 31 in. long. This rectangu­lar opening fits nicely between ceiling joists installed on 2-ft. centers. Usually, the hole is located in a closet or along a hallway. Once you select a spot for access to the attic, cut a pair of 2xs to fit between the ceiling joists and nail them 31 in. apart. The bottom edges of the blocking should be flush with the bottom edges of the joists. Take the time to measure the hole diagonally to make sure it’s square. After V2-in. drywall is nailed in place, you will have a 21V2-in. by 30-in. access hole.

If you are using blown-in insulation to insulate the ceiling, build a plywood or OSB curb around the access hole in the attic. Make sure the curb is tall enough (at least 12 in.) to keep the insulation from falling on your head every time you open the lid to the

attic. The lid can be cut from drywall and should be insu­lated with rigid foam board.

Instead of a simple lid for the access hole, you may want to install a pull-down stair kit. If you’re using the attic for storage and need to go up there on a regular basis, a pull-down staircase is the way to go. The stairs are factory-made and designed to fit in the 22V2-in. space between the joists. The rough opening must be longer, however—54 in. is common. Check the manufacturer’s specifications before you frame the opening.

CREATE ATTIC STORAGE. There is some usable space in most truss-roof attics. To make use of it, don’t lay sheathing directly on the joist chords of roof trusses, as trusses are not engineered for this. Instead, frame a storage platform above the joist chords, making sure that there’s room for insulation beneath the platform. You can support the platform’s joists on short (8-in.- to 12-in.-long) cripple studs nailed to the double top plates of nearby walls. Sheathe the platform with 1/2-in. plywood or OSB.

As explained earlier in this chapter, barge rafters extend beyond the end of a building, creating an overhang at the gable ends. The rafters are supported by 2×4 lookouts that fit into notches cut in the gable-end rafters. The lookouts run back to the first inboard rafter (or roof truss). At the bottom corner of the roof,

a barge rafter meets a gutter or fascia board, which extends along the eave and is fastened to the ends of the rafter tails.

There are a few tricks to making sure that these exterior trim details are done correctly.

If you plan to cover the trim with aluminum cladding, as we did on this house (see Chapter 7), the cutting and installation work is a little eas­ier. On the other hand, if the barge rafter and fascia will be exposed as finished trim, you’ll need to cut tight-fitting miter joints where the boards meet. Both types of installation will go more smoothly if you follow the steps described here.

Let the lookouts run long

I like to install lookouts long, then snap a line from eave to ridge and cut the lookouts in place. If you’re framing with rafters rather than with trusses, the ridge board can also run long at this stage. This process ensures a straight barge rafter. Hoist a supply of 2×4 lookout stock up to the roof, set each lookout in its notch, and secure the end of each one against the face of
the first inboard truss (or rafter) with two 16d nails. Keep the top surface of the lookout flush with the top edge of the truss. Now, before driv­ing a pair of 16d nails into each notch, move the gable-end rafter in or out to make the framing member as straight as possible. Nail all the look­outs in their notches, and leave them like this for now.

Make truss ends straight

If the truss tails have been set straight, begin to cut and install the gutter or fascia boards. If they’re not straight, snap a line across the top or bottom edges, then mark plumb cuts to line up the truss ends in the same plane. This is another exception to the “never cut a truss” rule. As long as you’re only making a small cutoff at the end of the truss (well away from joints and gussets), there’s no chance of structural damage. Check the eave overhang called for in the plans. Measure this distance on the gable-end trusses at opposite ends of the house. Then snap a line across all the trusses, going from one end of the house to the other. Mark the cut lines on the truss ends and make the cuts. This technique also works when building plans call for exposed rafter tails that must be cut in the same plane. Use a jig or pattern, such as the one shown in the top illustration on p. 130, to mark identical plumb cuts on the rafter tails. You can make the cuts from above, while standing on the top plate of the wall, or from below, while standing on a ladder or scaffolding.

Install the gutter or fascia boards

Although both gutter and fascia boards are nailed to the rafter tails, the distinction between the two is that gutter boards are later covered with trim (aluminum or vinyl cladding or 1x finish material). Fascia, on the other hand, is a finished surface. Some builders install 1x fascia boards over 2x gutter boards or subfascia, whereas others use the 2x stock as the finished fascia.

Obviously, smooth, accurate cuts are re-
quired to install fascia boards, whereas gutter

At this point, you need to add backing (some­times called deadwood) to walls that run paral­lel to the joist chords. The backing provides a nailing base for ceiling drywall (see the illustra­tion on p. 127). It’s easier to put the backing in now rather than after the roof is complete and hampered by sheathing. This is a good place to use knotty, crooked 2x stock. Nail the stock, one 16d nail every 16 in., to the double top plate of parallel walls so that the 2x backing overhangs the double top plate by at least 1 in. on both sides. Some builders use drywall clips instead of solid backing, but I like to fasten nails

Doing carpentry on the ground is easier than doing carpentry on top of the house. You really have to watch your step.

We handle the trusses carefully.

Plenty of bracing is required to tie the trusses together and to the rest of the house.

When the trusses are up, you can see what the completed house will look like.

INSTALLING BACKING FOR DRYWALL

into something solid. (Details on drywall instal­lation are covered in Chapter 9.)

This process is different for trusses that are allowed to expand and contract. In this case, nail flat 2×4 “ladder” backing between the joist chords on a parallel wall. Use truss clips to at­tach the backing to the double top plate of the wall, as explained on p. 124. This allows the trusses to expand and contract without stressing the drywall.

On small houses, trusses are generally engi­neered to obtain their support from exterior walls without needing further support from interior walls. Still, it’s not uncommon for trusses to cross over and bear on interior walls. In most regions, these trusses can usually be nailed directly to the interior wall with two 16d toenails on one side and one on the opposite side. This is not the case, however, if you live in a part of the country where the weather may be freezing one day and boiling the next. In areas with extreme temperature fluctuations, trusses must be able to expand and contract freely. Otherwise, drywall ceilings nailed to these trusses tend to crack. Check with your building department for the code requirements in your town or city. In addition, ask area builders what the local practice is.

Installing permanent brac­ing inside. Shown in the photo on the facing page, a diagonal brace from the top of a truss down to a wall plate helps hold the trusses plumb. Install a 1×6 or 2×4 catwalk on top of the trusses’ bottom, or joist, chord. The brace should be nailed into every joist chord and into the end-wall top plates (photo below). Nail­ing 2x bracing across the webbing provides the roof structure with additional rigidity (photo above). [Photo on the facing page by Don Charles Blom, courtesy Fine Homebuilding magazine © The Taunton Press, Inc.]

To secure a truss to a wall while still allow­ing it to adapt to fluctuations in temperature and humidity, use a truss clip, as shown in the illustration on the facing page. These clips, which are nailed both to the wall plates and to the truss, feature a slot that allows the truss to move up and down as it expands and contracts— just make sure the nail is slightly loose in the joist chord.

When bracing trusses, take time to read and follow the directions from the engineering com­pany. These, along with local building codes, must be followed to guarantee that the house will have a strong and stable roof. Most simple gable-truss roofs are easy to brace.

After four to six trusses have been installed, plumb the gable-end truss and begin bracing the roof. Use a level to plumb the end truss, then install a diagonal 2×4 sway brace from the double top (cap) plate of the exterior wall (where the gable-end truss is installed) to an inboard truss (see the photo on p. 124). The brace should extend at a 45-degree angle from the top plate and be nailed to the top chord (or rafter) or the webbing of an inboard truss.

If the gable-end rafter is plumb, the rafters tied to it at 24 in. o. c. should also be plumb.

When all of the trusses have been installed, nail in a sway brace at the other end of the roof. On longer roofs, use additional diagonal sway braces near the center of the house to further strengthen the roof. These are important braces. In a high wind, they will help keep your roof intact.

The next step is to stabilize the joist chords by nailing a long board (a 1x or 2x will do) on top of each joist chord near the center of the span. You can move this bracing to one side or the other if you need to accommodate an opening for attic access, storage space, or room for a heat­ing unit. Frequently a forced air heating unit will be set in this area. Nail this long brace to each chord with two 8d (for 1x stock) or 16d (for 2x stock) nails (see the bottom photo on the facing page). Additional 2×4 braces are often nailed at 45-degree angles across the underside of the raf­ter chords or webbing from the plate line to the ridge (see the top photo on the facing page). Nail these braces into each chord with two 16d nails. This provides lateral stability to the entire roof.

2x frieze block

Rafter

Double top plate

Stucco

When installed plumb, a frieze block provides backing for stucco.

2x frieze block

Siding

Trusses by themselves are rather fragile. They gain strength when they’re properly blocked and braced. I will now explain various blocking and bracing strategies, because this work needs to be done as the trusses are installed.

Hurricane clips and frieze blocks

A hurricane can tear a roof completely off a house. Hurricane clips, which are designed to prevent this, are required by code in some parts of the country. After the trusses are nailed in position, hurricane clips are easy to install from inside or outside the house. Drive nails into the trusses and the top plates of the wall (see the bottom left photo). Be sure to use the special short, strong “hanger” nails that are sold with the clips.

In many parts of the country, frieze blocks are required between trusses. I’m in favor of these blocks, which you can cut from the plentiful supply of 2x scrap that your crew has been collecting. Installed at the top of the wall, these 2x blocks connect the bottom chords or, depending on the truss design, the rafters of ad­jacent trusses. They provide extra rigidity near the truss ends (see the illustration at left).

I have seen firsthand how frieze blocks help hold truss systems together in high winds and earthquakes. They offer other benefits as well. The blocks can serve as exterior trim (with or without ventilation holes) if you plan to have an open soffit. If you are installing raised-heel trusses, as we did on this house, you’ll also need to install plywood or OSB baffles between the trusses to prevent attic insulation from spilling into the soffit area (see the top photo on p. 153).

Install a pair of frieze blocks after each truss is installed. Drive a pair of 16d nails

Hurricane clips tie trusses to walls. Required by code in many areas, these metal connectors are designed to fit around the bottom chord of a truss and against the top plate of a wall. Here, a volun­teer attaches a clip with an air hammer.

through the truss and into the end of the frieze block, then nail the frieze block to the top plate. You can cut a supply of blocks quickly on a chopsaw. Make sure you cut them to the correct length. If they’re too long or too short, you may force the trusses off of their layout. The normal block length for trusses spaced 2 ft. o. c. is 22У2 in. However, if the blocks will butt against gusset plates, you’ll need to take the gusset thickness into account.

After you’ve nailed the first frieze blocks to the gable-end truss, swing the next truss upright. Shift it right or left, as necessary, to obtain the correct eave overhang, then toenail it to the top plate with two 16d nails through the joist chord on one side and one 16d nail on the other side (see the bottom photo at right). Install the next several trusses in this fashion. As you raise each truss, tack a series of 16-ft. 1x4s (laid out 24 in. o. c.) near the ridge of the rafter chord to keep the truss stable and properly spaced (see the top photo at right).

An efficient way to work when installing roof trusses is to have a worker at each eave toe – nailing the truss to the wall and installing frieze blocks while one or two crew members work on the ridge, moving trusses into position and nail­ing 1×4 braces to maintain proper spacing.