Nail length

hello, thanks to all the help in my “gambrel” thread, it looks like ths might actually happen. so it brings up more questions. I have been told that the nails should fully penetrate the deck, protruding just a bit on the underside in order to avoid a tendency to work back out. is this so? I plannned to use a bostitch gun that can only go 1 3\4. probably won’t go thru the deck 3\4" + 7\16"cdx +felt
ww + 50yr gaf. are 1 3\4" coil nails ok? thanks, greg

Thats too long.

I think nails are supposed to penetrate like 3/8"-1/4" of the decking? So if that’s true then:

decking size + (shingle size * 2) + 3/8" = nail length

Honestly I never worried about length too much. I mean it’s a concern, yes but I don’t sit and calculate it for each job. We normally use 1-1/2" or 1-3/4 depending…

EDIT* Had a minute to look this up. Certainteed says nails must be long enough to penetrate 3/4" into the decking. If decking is less than 3/4" the nails must penetrate 1/8" beyond the deck.
So like I said, I wouldn’t worry about it too much. As long as you don’t have a cathedral ceiling or some other kind of weird exposure that requires short nails, you’re pretty much golden.

use 1 1/2" on lifetime on a clean deck

i thought they needed to protrude. this makes it easier, thanks
ps I assume you don’t always uniform setting from a gun no matter how you set it, so do you end up using the hammer along with the gun?

No you should not need to use a hammer with the gun if your pressure is right.
somtimes we reroof an area like a farmers porch were the custumer does not want to see nail heads so we will use 1" roofers with no problems. most of our shingle jobs are Timberline Ultra we almost never install three tabs anymore. We buy things like gun nails,felt and I&W by the pallett.


I always carried a hammer when using a gun. You get the occasional crooked nail or whatever that needs to be smacked with a hammer or pulled.

nail em on with the 1 3/4".
they will work fine.


I concur with Tar Monkey’s post. If you don’t go up with a hammer, then you’re a braver fool than I am.

Of course every roofer should have a hammer that should go without saying.
20oz estwing is the most common.