Can you repair roof felt from inside?
Short answer. Not on most Georgia homes. Here the felt or synthetic underlayment sits on top of the roof decking, under the shingles, so from the attic you only see the underside of the wood and cannot reach the felt at all. From inside you can trace the leak, catch water and mark the spot, but the actual repair has to be made from the roof.
Why it differs from what you may have read
Some older homes in other countries have roofing felt draped over the rafters directly under tiles, with no solid deck, so a torn felt can be patched from the loft. American homes, including nearly all Georgia homes, have plywood, OSB or board decking with the underlayment on top of it. Torn paper you see from the attic is more likely the facing of insulation or a radiant barrier than the roof felt.
What you can do from inside
- Trace the leak. With a flashlight during or after rain, follow wet trails on the rafters and deck uphill to the highest wet point.
- Mark it. Measure from a gable wall and from a vent pipe or other fixed point so a roofer can find the same spot from above.
- Catch the water. Put a bucket or tarp under drips and pull wet insulation back so the area can dry.
- Look for clues. Rusty nail tips, dark rings around a vent pipe, or water running down the chimney chase point to specific sources.
Why sealing from inside does not work
Spraying foam or caulk on the underside of the deck traps water in the wood while the leak keeps feeding rot. The water has to be stopped at the shingle, flashing or boot on top. See common causes of roof leaks and roof anatomy explained.