How to repair a leak in a roof: find it, replace the shingle or boot, or tarp it

How to find a roof leak before you buy anything

Look in the attic, uphill from the stain, because that is where the water got in. The stain on the ceiling is where the water ended up. It got into the roof somewhere above that, ran down the top of the underlayment or the underside of the deck, followed a rafter, and dropped when it hit a nail or a low point. On a 6/12 roof that trip can be several feet.

1. Go into the attic with a flashlight during a rain or soon after. Find the wet insulation or the drip, then look up at the underside of the deck.

   Check: you have found the entry when the wet streak on the wood ends. If it keeps going uphill, keep following it.

2. Look at every penetration above the stain: plumbing vents, bath and kitchen fan hoods, the chimney, skylights. A dark ring of wet wood around a vent pipe points at the boot.

   Check: stains that show up only in wind-driven rain often point at flashing along a wall or at the rake, and stains that show up in every rain point at a hole.

3. If the attic is dry, test with a hose. One person on the roof runs water on one small area at a time, starting at the eave and moving up. The other watches inside. Give each spot several minutes before moving higher.

   Check: the first spot that makes water appear inside is the entry. Starting at the top would wet everything below it and tell you nothing.

What causes a roof leak: shingle, flashing or pipe boot

On a roof that is otherwise sound, check the pipe boots first, then the flashing, then the shingles. A shingle leak is the easiest to see from the ground: a missing tab, a torn corner, a shingle lifted by wind. When the sealant strip lets go, the tab can flap until the nails tear through.

Flashing is the metal or membrane that turns the water where the roof meets something else. IRC R903.2.1 requires it at every wall and roof intersection, at every change in slope or direction and around every opening, and metal flashing has to be at least 0.019 in thick, the equivalent of 26 gauge galvanized steel. Along a sidewall, R905.2.8.3 requires the base flashing to be at least 4 in tall and 4 in wide, with its vertical leg under the siding. When that step flashing was skipped or the siding was installed over it wrong, the fix means pulling siding, and that is a job for a roofer or a siding contractor. A chimney wider than 30 in across the slope also needs a cricket behind it (R903.2.2), a small peaked roof that splits the water; if yours has none and leaks at the back, that is the reason.

Pipe boots often fail on a roof that is otherwise fine. The rubber collar around the vent pipe dries out and cracks in the sun long before the shingles wear out. The fix is a new boot. More caulk only delays it.

Materials and tools, with prices

Menards online prices on 2026-09-19. The shingle count per bundle is Owens Corning's 64 shingles per three bundles. Match the brand and color if you can; a new bundle will look darker than a roof that has had years of sun, and there is no fix for that except time. You also need a hammer, a utility knife with hook blades, a ladder that reaches 3 ft above the eave, and soft-soled shoes.

How to replace a shingle on a roof

This is the repair most people search for, and the step that trips them up is the course above. On a laminated shingle like Oakridge, the nails for the shingle above go through the top of the one you are replacing. You have to free both.

1. Pick a cool, dry morning. The sealant strips soften in the sun, and a hot shingle tears when you lift it. Owens Corning also asks for extra care handling shingles below 40°F, when they crack.

   Check: a tab lifts about an inch without creasing.

2. Slide the flat bar under the tab of the shingle directly above the damaged one and work it along to break the sealant strip. Do the same for the damaged shingle.

   Check: both shingles lift freely along their whole length.

3. Pull the nails that hold the damaged shingle: its own row and the row driven through it for the course above. Work the flat bar or shingle remover under each nail head and pry gently.

   Check: the damaged shingle slides out without tearing the one above.

4. Slide the new shingle in, aligned with its neighbors and the exposure of the course (5 5/8 in on Oakridge). Nail it where Owens Corning specifies: 6 1/8 in up from the bottom edge and 1 in from each end, four nails, or six where you need the high-wind pattern. Nails must be at least 12 gauge with a 3/8 in head, driven flush, and reach at least 3/4 in into the deck or 1/4 in through it. IRC R905.2.6 sets four nails as the minimum per strip shingle.

   Check: nail heads sit flat on the shingle, not cut into it and not standing proud.

5. Renail the course above through the new shingle, in the same nail line, next to (not in) the old holes. Put a dab of roof cement on any old hole you can reach.

   Check: no nail is exposed on the finished roof.

6. Seal the tabs you lifted with a small spot of roof cement under each. Owens Corning warns that too much cement blisters the shingle, so use about a 1 in dot.

   Check: press each tab down; it should stay flat.

How to replace a pipe boot

1. Break the seals and pull the nails on the shingles covering the upper half of the old boot's flange.

   Check: the top of the flange is fully exposed.

2. Pull the flange nails and lift the old boot off over the pipe. Look at the deck around the hole.

   Check: the wood is firm. If it's soft, the patch in the next section comes first.

3. Slide the new boot down the pipe. The upper part of the flange goes under the shingles above; the lower part lies on top of the shingles below, so water running down the roof passes over it. Nail it per the boot maker's instructions.

   Check: the rubber collar hugs the pipe with no gap, and the downhill edge of the flange sits on top of shingles.

4. Renail and reseal the shingles over the upper flange and put roof cement on any exposed nail head.

   Check: run the hose over it and watch the attic.

How to patch a hole in a roof, and when a tile needs a roofer

If a branch went through, or the deck around a leak has gone soft, the patch starts underneath. Strip the shingles back, cut the damaged decking out to the centers of the nearest rafters, and fit a new piece of 7/16 in OSB, $13.48 a sheet. Cover it with underlayment lapped under the old underlayment above, then shingle it in from the bottom up, weaving the new shingles into the old ones. If the hole is bigger than a sheet, or the rafters are damaged, it is a structural repair.

Clay and concrete tile are a different trade. IRC R905.3.2 limits tile to slopes of 2 1/2/12 and up, and R908.5 allows old tile to be reinstalled only if it is not cracked or broken. Tile breaks under a foot in the wrong place, so a tile repair often creates more broken tile than it fixes. Replacing a roof tile yourself makes sense only on a low, accessible section where you can reach the tile from a ladder.

How to tarp a leaking roof until the repair

A tarp buys time. It does not fix anything. A 12 ft by 16 ft heavy-duty tarp was $18.99 on 2026-09-19; the $9.99 blue one is thinner and won't last as long in sun. Lay it so it runs over the ridge and down past the leak, so rain from above lands on the tarp and runs off its lower edge. Roll the edges around 2x4 battens and screw the battens down, which spreads the load and keeps the fasteners out of the middle of the tarp. Each screw is a hole you will fix later, so use as few as the wind allows.

Roof safety: the OSHA rule and what it means at home

OSHA's rules cover employers and workers, not homeowners on their own roof. They are still the best guidance there is. Under 29 CFR 1926.501(b)(13), a worker doing residential construction 6 ft or more above a lower level has to be protected by a guardrail, a safety net or a personal fall arrest system.

For the ladder, 1926.1053 requires the side rails to extend at least 3 ft above the landing and the base to sit out about a quarter of the working length. A kit with an anchor, harness and lifeline was $114.99 at Menards on 2026-09-19. If you won't use one, stay off the roof and call a roofer.

Mistakes that cost money

Smearing roof cement over a cracked pipe boot is the classic. It holds for a season, then cracks with the rubber underneath. If you then pay a roofer for the boot you could have replaced for $12.99, that is about $291.

Replacing shingles when the leak is flashing costs the same way. At $343 for a shingle service call, a wrong guess is a whole repair spent on nothing, and the ceiling keeps getting wet.

Waiting costs decking. One sheet of OSB replaced by a roofer comes to about $53.82 after markup: $13.48 for the sheet and half an hour of labor, an allowance from the replacement guide, marked up 1.603. Wet insulation and drywall below are extra.

Nailing high, above the manufacturer's nail line, leaves the shingle held by fewer layers, and wind lifts it. The repair then needs a second repair.

Too much roof cement under the tabs blisters the shingle. A 1 in dot is enough.

When should you replace a roof instead of repairing a leak?

A repair is a good deal on a sound roof. It stops being one when the leaks keep moving. Signs that the roof itself is done: shingles curling or bald across whole slopes, several leaks in different places, soft decking in more than one spot. The NAHB life-expectancy study puts asphalt shingle roofs at about 20 years; at that age, one patch mostly buys time until the next.

If you are pricing the alternative, the roof replacement cost guide works out $15,133 for a typical tear-off on a 2,000 sq ft gable footprint, about $620 a square. A new layer over the old one is not always allowed: IRC R908.3.1.1 bans a recover over two existing layers, over a water-soaked roof, and over slate or tile. To size your own roof, the roofing calculator turns a footprint and pitch into squares, and the guide on measuring a roof for shingles shows how to take those measurements.

How much does roof leak repair cost? DIY or hire

A small repair runs about $291 to $343 from a roofer and $20.94 to $52.92 in materials done yourself. The roofer's price here is built from public numbers. The BLS put the national mean wage for roofers at $27.95 an hour in May 2025; the middle of the range runs from $22.24 at the 25th percentile to $31.44 at the 75th. Construction employers pay $51.96 in total compensation for every $36.13 in wages, so one roofer hour costs the company $40.20. A service call, in my allowance, is two roofers for two hours including the drive and the setup, 4 labor hours, $160.78.

Doing the shingle yourself with new hand tools ($27.23) and a new fall protection kit ($114.99) costs $195.14, which still saves $147.43 on the first repair. The kit and tools carry over to the next one. On a steep roof or a two-story eave the comparison changes, because the risk is yours and the roofer's crew does this every day. If your roof is high, steep or tile, pay the $343.