Asphalt shingle roof repair

Read the damage before you lift anything

Most shingle repairs go wrong at the diagnosis, not the nailing. A lifted tab and a creased tab look alike from the ladder, and the first wants a dab of cement while the second wants a new shingle. Get on the roof, run a hand along the course and press anything that looks off. A firm shingle that simply is not stuck down is a sealing problem. A shingle that folds along a line, or gives under the thumb, has a broken mat, and no amount of cement puts the strength back.

Storm damage needs one extra step before any of this: photograph it first, slope by slope, with something of known size beside each mark. The storm damage inspection guide covers reading hail against wind and what an adjuster wants to see. A repaired shingle is a shingle the adjuster can no longer inspect. Granule thinning with a firm mat is age, and the honest answer there is the lifespan guide, not a repair.

Replacing one shingle, in order

The drawing at the top of this page shows why there is no such thing as pulling one shingle. Each course hides its own nails under the course above. The course above drives its nails 3/4 inch below the damaged shingle’s top edge, straight through it, on a GAF Timberline HDZ laid at its 5 5/8-inch exposure. Leave those nails in and the damaged shingle tears rather than slides out. Every single-shingle repair is really a two-course job.

1. Break the seal on the course above. Slide a flat bar under its butt and work it sideways along the seal strip until the tabs lift. That exposes the damaged shingle’s own nails. Then break the seal on the course two up, gently, just far enough to reach the nails of the course above. Go slowly on an old roof. A brittle neighbour cracked on the way in is a second repair.
2. Pull the nails. First the damaged shingle’s own (four on a standard pattern, six on an enhanced one). Then every nail from the course above that lands within the damaged shingle’s width. Pop each one with the bar under the head rather than prying the shingle up around it.
3. Slide it out and look underneath. Torn underlayment, a wet deck or a soft spot changes the job. A soft deck is no longer a shingle repair, and the leak repair guide covers what that turns into.
4. Slide the new shingle in under the lifted course. Line its butt up with its neighbours so the exposure matches the course, and keep the vertical offset of the original pattern.
5. Nail it in the nail zone. On HDZ that is the marked band 5 13/16 – 7 5/8 inches up from the butt, nominally 6 7/8, with the end nails 1/2 – 2 1/2 inches in from each edge. Drive each nail flush: GAF’s sheet warns that overdriving damages the shingle and a raised head stops it sealing.
6. Re-nail the course above through the new shingle, in its own nail zone. Put each new nail just beside the old hole rather than back into it, and fill the old holes with a little cement.
7. Hand-seal every tab you lifted (next section). A seal you broke will not reliably re-bond by itself.

Re-sealing a lifted tab

A self-sealing shingle carries a strip of thermal sealant that bonds it to the course below once the sun has warmed it. GAF’s sheet is blunt about when that never happens: wind before the strip has bonded, surfaces that never got warm enough, or sealant fouled with dust. In those cases, it says, the shingle “may never seal”. A lifted but undamaged tab is usually one of those three, or a nail that has backed out and is holding the course off the deck.

Check for the nail first. Press the tab down; if it springs back over a hard point, find the head, pull it, and drive a new nail beside the hole in the nail zone. Then seal.

That is GAF’s hand-seal pattern for Timberline HDZ: four quarter-sized dabs of shingle tab adhesive on the underside, then press the shingle firmly into them. Lift the tab only as far as you need to get the gun under it. Cold, stiff tabs crack at the fold.

One limit: a creased tab sealed flat is still creased. The mat is broken along that line and the next storm will fold it again. Re-sealing is for shingles that are whole.

Temperature: when the shingle fights you

The GAF sheet sets no minimum air temperature for working shingles, and it would be wrong to invent one. What it does say is the thing every repair crew learns. Asphalt shingles are stiff in cold weather and flexible in hot, they break easily in the cold, and their edges get damaged in the heat. That makes a repair harder than new work at both ends of the year, because you are bending shingles that are already installed.

• Cold: breaking a seal on a cold morning cracks tabs. Wait until the sun is on that slope. If the cold is going to last, the sheet says to hand-seal, because the strip will not activate on its own.
• Hot: soft shingles scuff under boots and the sealant smears. Work the slope early, before the sun is on it, and keep foot traffic off the repaired area.
• Storage: the replacement bundle should live flat, covered and below 110°F, per the same sheet. A bundle left in a hot truck bed sticks together.

Matching a colour that is no longer made

Shingle lines and colour names change, and a ten-year-old roof has weathered away from the colour on the bundle anyway. In order of preference:

1. Leftovers from the original job. Garages and attics often hold a partial bundle. It is the right product, and the colour has aged indoors rather than on the roof, so it will still read slightly fresh.
2. Borrow from a hidden slope. Take shingles from somewhere no one looks, such as the back of a dormer, behind a chimney or a rear porch roof. Put them on the visible repair, then fill the hidden spot with the nearest new colour. The weathered match goes where it is seen.
3. Take a sample to the supplier. Pull a shingle (one you are replacing anyway) and match it in daylight, profile first, colour second. A laminate patched into a 3-tab roof shows from the street whatever the colour. The architectural vs 3-tab comparison covers why the two do not mix.

New granules weather towards the roof around them, but do not promise a homeowner the patch will disappear. Say it will be visible up close and explain why. That conversation costs nothing up front and a lot afterwards.

Repairs and the warranty

Do not tell a homeowner that a repair voids the shingle warranty, or that it cannot. That turns on the wording of the product’s own limited warranty. What a shingle warranty is written around is the product installed to the manufacturer’s instructions. A repair done to those same instructions, with the same nail count, nail zone and cement, puts the roof back in that state. A repair done any other way gives the manufacturer a reason to look hard at a claim.

Two lines from GAF’s sheet are worth knowing. Shingles that never sealed because wind got to them first, the surface never got warm, or the sealant was dirty are described as “not a manufacturing defect”. And the six-nail pattern is required for enhanced wind coverage on certain products. A four-nail repair on a roof sold with that coverage is the weak link. The exact terms sit in each product’s limited warranty, and contractor-registered system warranties can add their own conditions. Read the one that applies before you touch the roof. The roofing warranty guide sets out how manufacturer, workmanship and system cover differ. If an insurance claim is open, the claim process guide comes first.

When repair stops making sense

The roof tells you, usually while you are breaking seals. If the shingles around the damage crack as you lift them, the mat has lost its flexibility. Each repair will now damage more shingles than it fixes. The same goes for granule loss across the whole field rather than one spot, or a third callout to the same slope.

The money side of that line is worked through in the repair-or-replace crossover on the repair cost guide, and the age side in how long asphalt shingles last. Before quoting either, walk the whole roof with the roof inspection checklist. A missing shingle is often the visible part of a flashing or ventilation problem. Leaks that show up beside walls, chimneys and pipes are flashing failures, and the flashing types guide covers them, not this one.

Safety: the six-foot line

A one-shingle repair is a short job, which is exactly why people skip the harness. OSHA does not make an exception for short jobs. Under 29 CFR 1926.501(b)(13), workers doing residential construction 6 feet or more above a lower level must be protected by a guardrail, a safety net or a personal fall arrest system. If the employer can show those are infeasible or create a greater hazard, it must work to a written fall protection plan instead. The rule presumes they are feasible, so the burden of proof sits with the employer.