How do you seal roofing nails?
Short answer. Most roofing nails should not need sealant at all, because they are hidden under the next course of shingles. Exposed nail heads, such as on the last ridge cap, some flashing or a vent flange, get a dab of roofing sealant that fully covers the head, and a nail that has backed out should be re-driven or replaced first, not just caulked over.
Where exposed nails are normal
- The final ridge cap at each end of a ridge, which has to be face nailed.
- Some counterflashing and trim pieces.
- Parts of vent flanges, depending on the product.
Exposed nails anywhere else in the field of the roof, often called shiners or high nails, usually mean a nail was placed wrong or has backed out.
How to seal an exposed head
- Make sure the nail is tight. If it moves, replace it.
- Clean off dust and loose granules and let the surface dry.
- Apply a roofing sealant that is compatible with asphalt shingles, covering the head and a little beyond it.
- On a ridge cap, press a few loose granules into the sealant to shield it from the sun.
Fixing a popped nail
A nail that has pushed up under a shingle can punch through it and lets water follow the shank. Lift the shingle carefully, pull the nail, drive a new one slightly to the side into solid wood, put sealant in the old hole, and press the shingle back down. Roof cement smeared over a raised nail usually fails within a season or two.
Do not overdo it
Globs of sealant across the roof can trap water and hide the real source of a leak. Sealant also breaks down in Georgia sun, so any sealed spot needs checking every few years.