How do you fix roof felt that is torn or exposed?
Short answer. Roof felt is the underlayment beneath the shingles, and when it is exposed or torn, usually after shingles blow off, it needs to be covered quickly: patch small tears with a piece of new underlayment slipped under the layer above, or cover the area temporarily until shingles can be replaced. The permanent fix is always new shingles over sound underlayment, because felt alone is not designed to face sun and rain.
What felt does
Asphalt-saturated felt, or the synthetic underlayment that has largely replaced it, is a secondary water barrier. It catches water that gets past the shingles and protects the deck during installation. It is not meant to be the roof, and exposed felt dries out and tears in sun and wind within weeks.
Short-term patch
- On a dry day and a safe, low roof, lift the shingles directly above the damaged area.
- Cut a piece of new underlayment large enough to cover the tear with generous margins.
- Slide its top edge under the existing felt or shingles above, so it laps like a shingle and never sits on top of the layer above it.
- Fasten the patch with cap nails where the replacement shingles will cover them.
- If shingles cannot go back on right away, the area needs a properly secured temporary cover.
Permanent repair
- Replace the missing shingles, matched as closely as possible, nailed on the manufacturer's nail line and sealed.
- Check the deck under the exposed area for water damage.
- If felt is torn across a large area or the roof is older, the roof may be due for replacement.
Is it storm damage?
Shingles blown off in a windstorm are a classic covered peril on many homeowner policies, depending on the policy and the deductible. Photograph the exposed felt, the missing shingles and any shingles in the yard before anything is repaired. See synthetic underlayment vs felt and wind damage to roofs in Georgia.