How to fix a roof leak: find where the water gets in, tarp it safely and choose the right repair

How to find a roof leak from the attic

The stain on your ceiling only shows where the water dripped off, not where it entered. HUD's inspection guide puts it simply: look for signs of leakage in the attic and trace the path to its source.

1. 01

   Go up in daylight after rain

   Take a strong flashlight and walk only on joists or boards, never between them on the ceiling.

2. 02

   Start above the stain

   Look for wet insulation, dark streaks on rafters and roof boards (sheathing), and drips on nails poking through the roof.

3. 03

   Follow the trail uphill

   Water runs down rafters and the underside of the roof boards. Track the darkest, wettest line upwards until it stops: that is close to the entry point.

4. 04

   Check every penetration

   Chimney, plumbing vent pipes, exhaust ducts, skylight shafts and the joints where a lower roof meets a wall are the usual suspects.

5. 05

   Look for daylight

   With the attic light off, pinholes of daylight around nails, vents or flashing show gaps.

6. 06

   Mark the spot

   Push a long nail or a piece of wire up through the wet spot so you or a roofer can find it from outside.

7. 07

   Inspect from the ground

   Use binoculars to check the matching area outside for lifted or missing shingles, cracked flashing or debris in a valley.

The hose test

If it has stopped raining, a helper can recreate the leak. One person stays in the attic with a flashlight; the other runs a garden hose gently on the roof, starting low and moving upwards one section at a time, a few minutes per section. Water from above runs over the lower sections, so working bottom-up tells you exactly which area lets it in. Do this only from a ladder or a low, dry, walkable roof.

Leak or attic condensation?

Not every wet attic is a leak. HUD lists rusting nails, wet or rotted roof boards and heat buildup as signs of poor attic ventilation, and frost or droplets spread evenly across the underside of the roof in cold weather point to warm, moist air from the house condensing there. A leak leaves a trail that starts at one point and gets worse with rain.

Temporary roof leak repair: tarps and quick patches

A temporary fix keeps rain out until a roofer can make a proper repair. Do the parts you can do safely and leave the rest.

From inside

• In the attic, put a bucket or a sheet of plywood on the joists under the drip and soak up wet insulation.
• If the water is pooling on the ceiling below, see the ceiling leak guide before you do anything else.

Tarping a damaged roof

Plastic sheeting is the standard emergency patch after wind or storm damage. FEMA describes temporary roofs as sheeting secured with strips of wood fastened with nails or screws, and the program's blue roofs are designed to last about 30 days. OSHA's guidance for crews doing this work adds practical points that apply at home too:

• Choose a non-reflective tarp with a textured surface to reduce slips.
• Get the tarp roll secure before lifting it onto the roof; it can take more than one person.
• Wait for the roof and tarp to be dry; dew, fog and rain make sheeting slick.
• Mark weak areas of the roof deck and keep everyone out of rooms below while people work overhead.
• Cover a large enough area that water from above runs over the tarp, not under it, and fasten through wood strips rather than through the bare sheet, so wind cannot tear it at the holes.

After a federally declared disaster, the US Army Corps of Engineers sometimes runs Operation Blue Roof, which installs temporary roofing free of charge on eligible primary homes with less than 50 % structural damage; your local emergency management office announces when it is open. Local governments also hand out free tarps after some storms.

What a proper roof leak repair involves

A lasting repair follows one rule: every layer must overlap the layer below it shingle fashion, so water is carried out and down. A good roofer will:

• Replace damaged flashing rather than coat it, tucking step and apron flashing at walls and chimneys under the wall's weather barrier.
• Replace vent boots whose rubber has cracked, and reseal around penetrations with proper flashing pieces.
• Replace missing or cracked shingles and check the underlayment beneath. HUD calls for at least one layer of 15-pound felt on normal-slope roofs and two on low slopes.
• Rebuild worn valleys and clean debris from valleys and gutters.
• Fit ice dam protection at the eaves in cold climates: HUD says it should reach 2 feet past the inside face of the exterior wall on a normal-slope roof and 3 feet on a low slope.
• Repair rotted roof boards found under the leak before re-roofing that area.
• Check the attic for wet insulation and air leaks while they are there.

Interior repairs come last, once the leak is fixed and the ceiling is dry.

Repair or replace your roof: the signs

Other signs a replacement makes more sense than another patch:

• Leaks in several places at once, or in new places each storm.
• Two layers of asphalt shingles already; HUD says no more than two should normally be in place.
• Sagging roof deck or widespread soft spots.
• Daylight through the roof boards in many places.

Roof leaks from ice dams

Ice dams form when heat from the house melts snow higher up the roof and the water refreezes at the colder eaves. The meltwater trapped behind the ridge of ice finds gaps in the shingles and leaks into the attic, walls and ceilings. Our ceiling leak guide covers the damage inside; here is the roof side.

• Right now: a long-handled roof rake used from the ground removes snow, though the University of Minnesota Extension notes it can damage roofing. In an emergency, channels through the dam let water drain; the Extension suggests hosing with tap water on a warm day, working up from the lower edge, and warns the channel only lasts days.
• Avoid: Minnesota's Department of Commerce advises against chipping ice, chemicals and heat, which damage shingles and gutters, and says heat cables shorten roof life. If the ice dam is already causing damage, it suggests a professional removal service that uses steam.
• For good: seal the air leaks from the house into the attic first, then add insulation; Minnesota's energy office suggests at least R-50 where space allows. A contractor can find the leaks with a blower door test and an infrared camera. The Extension does not recommend powered attic fans for ice dams.
• Stay off icy roofs. Winter roof work is a job for professionals.

Questions to ask a roofer

• Where exactly is the water getting in, and can you show me photos?
• Will you replace the flashing or only seal it?
• What underlayment and ice dam protection will you use at the eaves and valleys?
• Will you check the roof boards and the attic for hidden damage?
• Is this a repair I can expect to last, or is the roof near the end of its life?
• Are you licensed and insured where I live, and will you give the scope in writing?

Sources

Official and university guidance, checked on 27 October 2026.

• HUD · Residential rehabilitation inspection guide ↗Tracing leaks in the attic, binocular inspection, flashing, valleys, skylights, roof covering lifespans, underlayment, ice dam flashing widths, signs of poor attic ventilation.
• OSHA · Hurricane eMatrix: roof inspection, tarping and repair ↗Fall protection at 6 feet, ladder angle and 3-foot extension, 10 feet from power lines, textured tarps, dry surfaces, lifting tarp rolls.
• OSHA · Portable ladder safety quick card ↗Three points of contact, quarter-length base, top three rungs, staying centered, power lines.
• FEMA · Temporary roofing can help get you home ↗Sheeting fixed with wood strips, 30-day design life, eligibility for free temporary roofs.
• University of Minnesota Extension · Dealing with and preventing ice dams ↗How ice dams form, roof rakes, emergency channels, air sealing then insulation, blower door and infrared testing.
• Minnesota Department of Commerce · Got ice dams? ↗Avoiding chipping, chemicals, heat and heat cables; steam removal; R-50 attic insulation.