Installing Three-tab Shingles

Load the roof. If possible, have the shingles delivered via a boom directly onto the roof. If the slope is shallow so there's no danger that the shingles will slide off, scatter the shingles on the roof so they will be in easy reach. Otherwise, stack them near the ridge in a way that prevents them from sliding or on a roof-jack platform (see photo).

Snap horizontal chalklines to help you keep the courses straight. First, snap a line for the top of the starter course, whose bottom will be flush with the WSU or felt underlayment (which overhangs the drip edge by 1/2 inch). Then snap lines for every course or every other course. Assuming that the shingles have a 5-inch reveal, snap these lines in 5-inch increments, starting at the bottom of the underlayment.

Install a continuous starter strip or full-sized shingles, which are simply turned downside up. Often, however, a starter course is made of cut shingles. Place the shingle upside down on a sheet of plywood and use a straightedge to cut it 7 inches wide; you will use the portion with no tabs.

Starting at one end, place the starter shingles downside up so the self-seal strip is near the bottom. The top should be aligned with the chalkline and the bottom should be flush with the bottom of the underlayment.

Attach each starter shingle by driving three nails along its top edge. Fastening along the top edge assures that nailheads will not be exposed.

To avoid ending up with a narrow strip of tab along one of the rakes, lay out a full course of shingles and adjust their position as needed.

To attach a shingle, align it with the layout line and drive nails 1/2 inch above the cutout slots (including the half slots at each side). Drive a nail at one end first, then drive the others. If you are using a power nailer, drive nails by squeezing the trigger and bouncing the nailer's tip onto the shingle.

For a racking or midroof pyramid layout method, snap two vertical lines (called bond lines) near the center of the roof, the appropriate distance apart. Check them with a framing square or measure so the lines are parallel with the rake ends. It's better to use the factory edges of a half-sheet of plywood as a guide.

To roof around a dormer or other obstruction, install shingles all the way up and run at least one course past the obstruction. The bottom of these courses must be nailed higher than usual so you can slip shingles under them later. Now you can snap a new bond line to align the shingles on the other side.

Install four or five courses of shingles along the bond lines in an alternating pattern as shown. Take care that the shingles are correctly aligned with consistent reveals. Later, you will need to lift up the outermost ends of the shingles on each side in order to slip in a shingle, so don't drive the outermost nails now.

Starting at the racked shingles, fill in the courses. Align the shingles with the horizontal lines and nail them in place. Note: In areas with high winds, it is common to drive two nails above each cutout line.

Shingles often have small cuts on the top and sides that can be used as guides for horizontal and vertical alignment. Use these whenever there is no layout line. Also, roofing hatchets and some roofing nailers have adjustable guides.

To easily check your work, or if you find the guide on the nailer awkward to use, make a simple plywood jig like the one shown as a guide for the 5-inch reveal.

If the roof is steep enough that you could slide off, install roof jacks and planks to keep you stable and safe. A scrap of roofing laid upside down beneath the heel of the jack will keep it from denting the shingles.

When you encounter a plumbing vent pipe, shingle up to it so the flashing will rest on a row of shingles below the pipe. You may need to cut out part of the rubber flange so it fits over the pipe. Apply roofing cement (a caulk tube is usually the neatest and easiest method) where it will rest on top of shingles.

Slip the flashing over the pipe and press it in place. Drive nails around the perimeter as recommended by the manufacturer.

Roof around the vent. Cut the upper shingles so they fit snugly but do not ride up on the flashing's raised portion; the shingles should lie flat at all points. Where shingles overlap the flashing, attach them with roofing cement rather than nails. Cover any exposed nailheads with dabs of roofing cement.

Apply flashing at a wall. Where a wall is perpendicular to the roofing (shown), slip pieces of step flashing under the siding. Apply a flashing piece, then a shingle, then flashing, as you would apply step flashing for a chimney. If the roof meets a wall that is parallel to the shingles, roof up to the wall, then slip a long, continuous piece of flashing under the siding and on top of the shingles.

When you reach a peak or hip, shingle all the way up the first side (until the reveal portion of the shingles is within 4 inches of the peak) and cut the shingles just below the ridge. Shingle the other side and allow these pieces to overlap the ridge by no more than 4 inches.

To cut ridgecaps, turn shingles upside down and cut off single tabs. Angle the cuts slightly so the nonreveal portions will not be visible when the caps are installed. Make a cut on the backside, then bend and break the shingle. Using a 5-inch reveal, estimate the number of caps needed. Prepare the ridge by snapping chalklines 6 inches on each side.

Install ridgecaps along the lines, leaving a 5-inch reveal. Drive the nails about 1-1/2 inches from the sides and just below the self-sealing strip. Shingle to the middle of the ridge, then start from the other end. Where the ridgecaps meet, install a 5-inch-wide strip. Cover nailheads with dabs of roofing cement.

If you have a hip that runs into the main roof, cover the area with WSU when you are installing the sheathing; cut the WSU so it lies flat at all points. Then cover the resulting V-shape notch with another piece of WSU. When you install the shingles, leave one shingle unnailed so you can later slip a ridgecap under it.