How do you repair a leaky roof?
Short answer. Repairing a leaky roof means opening the shingles where water gets in, fixing whatever failed underneath, whether a boot, flashing, a nail or torn underlayment, replacing any soft decking, and rebuilding the shingle courses with proper laps and nailing. Sealant smeared on the surface is a stopgap, not a repair.
What the repair actually involves
- Open the area. Break the adhesive seals of the shingles above and around the leak and pull their nails so the underlayment is exposed.
- Read the evidence. Dark, soft or delaminated decking shows how far water has spread. Rusted nails and stained underlayment trace the path uphill to the entry point.
- Fix the cause. Replace the cracked boot, the rusted step flashing, the torn underlayment, or the shingle with a hole in it.
- Replace bad decking. Cut soft wood back to the rafters and install new sheathing of the same thickness. Rotted decking is how people put a foot through a roof.
- Rebuild the layers. New underlayment slipped under the existing layer above, then shingles woven back in course by course, nailed in the nailing zone, with tabs hand-sealed.
Tools and conditions
You will need a flat bar, hammer, utility knife with hook blades, roofing nails, roofing cement, underlayment and matching shingles. Work in dry, mild weather. Georgia summer afternoons make shingles soft and slick, and pop-up thunderstorms arrive with little warning.
When to hand it off
Leave it to a professional if the roof is too steep to walk comfortably, two stories, or wet, or if the leak is at a chimney or skylight where flashing has to be rebuilt. If you find leaks in several places, or shingles crack when you lift them, a repair may not hold. Compare signs you need a new roof and check common causes first.