I’ve always considered it necessary to caulk any exposed nail heads on a shingle roof - there shouldn’t be many.
I heard an opposing opinion recently. The claim was that nails have to pass through a minimum of two layers of shingles. The shingles are asphalt backed and this asphalt forms an adequate seal around the nail.
I must admit I’ve seen many builders that do not seal the nail heads.
I suppose there are differing views on this but does anyone know from actual experience whether unsealed nail heads leak?
probably won’t leak right away, but when the head starts to rust, and allows water down to it’s stem, then it could. Expansion and contraction will also cause some movement on and around the nail. This may break that seal.
I wouldn’t argue with anyone over it, because it’s not really a huge deal, but it is just a good idea.
Go order the Certainteed “Shingle Applicator’s Manual” that is referenced in another recent thread. Refer to pages 82, 84 and other pages as well.
I’ll have to find the photo but I have one where on the top the roof it shows a small hole where the nail used to be but from the bottom inside the attic you can see a tiny spot of daylight through the hole, and then around the hole for about two feet in all directions, wood rot and mold, including the rafters. I point it out on the report as a minor item that can develop into a major if left unresolved. My brother was a professional roofer for many years and he hates it when he sees it. Calls it unprofessional and lazy, but then his butt is tighter than even mine. His solution is to seal it with roofing bull and then to take two pieces of the scrap shingles and rub them together over the spot until the minerals cover the spot completely making it disappear and blend right in with roof. You should see my new roof that he and I installed. It is a thing of beauty.
Perfect answer Doug. I used to take granules from the gutter and do the same thing when sealing the nailheads. I don’t understand why you would not seal these as a roofer. you spend all week putting a new roof on for someone, and then on the last day, you shank it, cuz you don’t want to go get the caulk gun or trowel? I don’t get it.
It may not appear to be a huge deal at the moment, but it sure could turn into one. IMO exposed nail heads should be covered with an acrylic water proof sealant.
it has been my exprience that un treated shiners will leak with time…even treated they should be checked every couple years along with the rest of the roof for caulk shrinkage …
That’s Certainteed’s recommendation as well.
All week to do a roof? jeez, we do them in a day!!!
Just kidding. You make a good point, why go through all the hard work and leave out the easiest part. Makes no sense.
Well Peter, getting up that ladder with a sore back, bad knees, hangover and trying not to spill your darn beer takes time!! And time is money right?
They should be sealed. As the shingles get older and more brittle water seapage can occur around the fastener penetration.
You hit the nail right on the head.
Sorry, couldn’t help myself 
“Usta could” do a lot of things in a day that now takes a week. You know what I mean. Now that I am a little older I don’t care as much neither.
This says it all.
**I mostly see the exposed nail heads at the ends of the cap shingle laps. I carry a can of the rubberized auto undercoating that can be found at most auto parts stores. It does a great job, is designed for exterior use and has a relatively long life span. It comes in a spray can and after using it, it can be upturned and the nozzle can be cleared just like a spray paint can. I keep it in the back of my jeep. **
**I know—I know—we are not supposed to perform any repairs but I do this rather than list it as a maintenance issue since the majority of my clients cannot or will not go on the roof. The buyers are always appreciative. **
Not a bad thing… I fix a lot of little crap that I’d rather not write up!
Who among us hasn’t used a screwdriver handle to whack down a hinge pin? let him cast the first stone…:mrgreen:
In general- shingle manufacturers consider any sealant a temporary fix and recommend replacing shingles with exposed nails. Realistically, most of the time it won’t happen.
There will always be the final hip or ridge cap shingles with exposed nails though.
I recommend that they always be sealed, but as anyone knows, even any caulking of plastic roofing cement will dry out, become brittle and crack away from adhering within about 5 years.
The best way is a combination of what was stated about the granule embeddment, but use a small scrap of rectangular shingle and use enough roof cement or caulk to adhere the shingle scrap in place.
Now, since the sealant is not exposed to the UV rays, it will last a lot longer, with a protective shingle on top, just in case.
Ed
Thanks for all your replies. I would give you a star but that feature seems to be gone.
If you dont repair an exposed nail, it can keep pulling up, which in turn creates a leak.
I guess I don’t get a chance to earn any atta-boys anymore.
Also, unless the rules get revised, I can not see my posts unless a moderator approves them first.
If you remember that old TV show with Chuck Connors, called “Branded”, where they unceremoniously ripped off his stripes at the beginning of each episode, that is how I feel posting here now.
Ed