How to Fix a Small Roof Leak from Inside the Attic

You can temporarily fix most small roof leaks from inside the attic using roofing cement, plastic sheeting, or expanding foam applied directly to the leak source on the underside of the roof decking.

1. Follow the Water Trail Up. Go into the attic during daylight hours and look for wet spots, water stains, or actual dripping. The leak point on the roof is usually uphill from where water appears inside. Follow any water trails back to their highest point. Mark the spot with chalk or a flashlight beam if working in darkness.
2. Clear Your Work Zone. Move any insulation, stored items, or debris away from the leak area. You need clear access to the underside of the roof decking. If insulation is wet, remove it completely as it can harbor mold and lose effectiveness.
3. Dry and Degrease. Wipe the area dry with rags or towels. Remove any loose debris, old caulk, or flaking material around the leak point. The surface needs to be reasonably clean for your repair material to adhere properly.
4. Seal the Breach Fast. For nail holes or small cracks, squeeze roofing cement directly into the hole and spread it around the area with a putty knife. For larger areas, cut a piece of plastic sheeting or roofing membrane 6 inches larger than the damaged area and press it into a thick layer of roofing cement. For emergency situations, expanding foam works temporarily but isn't a long-term solution.
5. Redirect Flow Away. If water is still dripping while you work, nail a small board or shingle at an angle above the leak to direct water into a bucket. This prevents further damage while your repair cures.
6. Plan the Real Fix. Check your repair after the next rain to ensure it's holding. Remember this is a temporary fix. Schedule proper exterior roof repair as soon as weather permits, as interior repairs don't address the root cause and won't last long-term.