Reroofing 101

If your roofing gets damaged, moisture will find a way inside your home sooner or later, potentially causing more problems inside. Here's how to reroof safely and effectively.

Removing the Old Roofing

Step 1—The first thing to have when working on the roof is a safety harness with a roof hook. Always wear your secured harness as soon as you step on the roof. Also, use safety glasses as nails and roofing flying out can hit you.

Step 2—You can peel off the shingle with a roof spade (Figure 1) with a serrated front edge to pry up the shingles by sliding it under the layer of roofing and then pushing down on the handle to lift the front of the blade and the roofing with it. It is easier if you remove the cap first and then remove the shingles from the top down, a few rows at a time.

Inspect the Decking for Cracks, Gaps, and Nails

Step 3—Once the roof deck is cleaned down to the boards, inspect the decking for cracks or other defects that may even require adding sheeting to the deck. Inspect for protruding nails or other objects to get a smooth and even surface. Use a push-broom to sweep the overall surface of your deck.

Inspecting the Existing Metal Drip

Step 4—Check the existing drip edge (Figure 2) to make sure it has been properly installed. It is critical that the drip edge along the bottom of the roof slope be placed 1/2-inch to 3/4-inch away from the facia—to keep the water away—and it should be nailed with roofing nails every 16 inches.

Step 5—The drip edge at both ends of your gable roof, however, will be placed right against the decking boards, and on top of the membrane and the felt paper.

Applying the Underlayment

This layer requires two or three rows of ice and water shield “membrane” and the remaining surface covered with felt paper.

Step 6—Since the edge of a roof is not always perfectly straight, you have to measure the width of the membrane and snap a line on the roof deck with a chalk line. This will be your guide to place the membrane straight and without wrinkles.

Step 7—Making sure that the end of the membrane is under the drip edge at the rake end of the roof, start unrolling the first strip of membrane from the left rake edge, with the edge band of tar at the top (Figure 3), lining it up to the chalk line while removing the top half of the protective film underneath so that the membrane can stick to the roof deck up to about three feet from the opposite end.

Step 8—Without pulling off any more of the film, lay the membrane flat and cut it so that it will cover up to the edge of the roof rake.

Step 9—Finish peeling off the top section of the film and press the membrane down to stick it to the deck the rest of the way and under the drip edge at the end.

Step 10—You can now staple the membrane down every two to three feet, on the band of tar at the top to keep the wind from getting underneath. The other half of the film can be peeled off next (Figure 4). The subsequent rows of underlayment will overlap the previous row to the printed line. Two rows of that membrane will likely be required at the bottom, with the rest of the deck covered with felt paper, every row stapled down as you go.

The Starter Strip

The starter strips are an integral part of roofing to cover shingle joints and tabs cutouts. They also provide a strip of tar around the perimeter of the roof to hold the shingles down. They’re about half the width of a regular shingle with a strip of tar along the bottom edge. Three-tab shingles cut in the length to remove the three tabs is a common practice, however, to make the starter strips (Figures 5 & 6).

Step 11—After cutting the tabs off, cut the length of half a tab from the rake end of the first starter strip to offset from the first-course shingles.

Step 12—Put down that start piece on the roof edge, overlapping the rake and the metal drip by 1/4”, to lead the water away from the eaves.

Step 13—Use 4 nails in each start strip piece, 1-inch from the top edge, to secure them in place. Cover the roof length leaving the same overlap at the other end, and then cover both roof rakes.

Shingling the First Course with 3-tabs Shingles

Step 14—You can now start the first course (row) of shingle starting on top of the first start strip shingle installed, lining it up with the end and bottom overlap.

Step 15—Secure it in place with roofing nails just below the adhesive tar strip, one inch (25mm) from the ends, as well as right above the two tab cutouts for a roof pitch between 15° and 60°, and one inch (25mm) over on each side of the tab cutouts for roof pitches above 60° (Figure 7).

Step 16. Keep adding shingles to the first course to the full length of the roof using the appropriate method of nailing.

Subsequent Rows in a Pyramid Fashion

Step 17—You can start the 2^nd row by cutting off the length of half a tab from the rake end of the first shingle in order to set it back that same amount from the joint of the underlying piece. The cut off sections will be used at the other rake end.

Keep building it up cutting off half a tab more every time you start a subsequent row creating a pyramid-shaped pattern for about five or six rows. With this method, you can nail down many more shingles before moving over for the next batch.

The Roof Cap

When you reach the top on both sides of the roof, you’ll want to cover the peak with a cap that will cover the shingles on both sides, past the tar strip.

Step 18—You make the roof caps from regular shingle by cutting them in three sections, through the center of the tabs, then trimming each side at a slight angle, making the top narrower than the center. Make as many as 6-1/2 pieces for each shingle length of the roof peak.

Step 19—Wrap the first piece across the peak at on end of the roof and nail down with a nail on each side on the top part of its tar strip. Wrap the subsequent cap pieces over the previous piece, covering the tar strip (Figure 8). The last piece at the other end will be from one of those pieces after the top black part is cut off leaving the tab part just below the tar strip. It can be glued on with a roofing pitch.