Cutting off protruding roofing nails - Damage roofing?

[newbury]

That was my first inclination, but unless they are REALLY whacked flat, doing this still leaves a dangerous point exposed, and I figured that whacking them really flat would actually put a lot of vibration/motion into the head of the nail where I least want it, especially risking that I actually drive them back out enough to raise the nail heads. A quick cut should disturb the nail shaft very little (except for the heat). I thought of a mechanical cutter/nipper too, but a lot of what I'm concerned about are nails that are broken out the side of the rafters where the framers missed getting them centered. These are hard to get cut clean, but with the disk, I can cut and buff them flat or slightly recessed against the rafter.

- Jay

I've used a metal bar placed against the nail and a hand sledge to make sure they bent over. It sort of cinched them in. If you just want to cut them I've found a sawzall to be a wonderful tool. It gives me reach. A few years ago I replaced a the surface of a deck I had installed with ring shank nails. Those nails don't pull. I'd slip the sawzall blade between the deck board and the joist and just cut away, easy as cutting anything.

The cut off wheel will work but require close proximity. The sawzall gave me reach.

 

[breadtrk]

I would cut them at all. That leaves just the 1/2" of nail holding the shingle, good wind and they will be gone, the longer nail may loosen in a wind but it keeps the shingle there to reseat on the next sunny day. Even normal heating and cooling cycles moves the nail, the longer shank stays there to provide friction as it moves up, thus making the roof last much longer. With no extra, every micro millimeter it moves out, it is incrementally easier to move out every time after that.

Ask any roofer about nails walking out of the roof. It is real and it happens.

 

[GaryM]

I agree with breadtrk about not cutting them short. But if I were going to cut them I'd go with the Channelock Nippers rather than the cut off wheel. Less noise and I'm sure it would be faster as well.

 

[EddieWalker]

You want to leave enough of the nail protruding from the wood so it still has as much grip as possible. The reason the nails stick out through the decking is that you need enough of the shaft of the nail passing through the wood to hold it in place. If you leave a quarter inch, you will be fine. If you go less then that, it's questionable. Never cut them off flat, that will weaken the hold of the nail and cause failure of the shingles.

Eddie

 

[ultrarunner]

Most here have tongue and groove redwood sheathing over exposed areas and god help the roofer with shiners...

Never had any problems with shingles blowing off... do get gusts to 100mph very rarely.... no tornados yet.

 

[JRobyn]

Thanks for all the input. It's done. Went with the cutoff wheel. All good, except for a nice coating of nail/wheel debris all over me, and the smell of burning plywood where I had to burn through the splinters that had broken down around the nail tips. We kept a close watch for any smoldering for several hours. After the first one or two, it was obvious that the heat generated was minimal, and probably only raised the temp out at the nail head to a couple hundred degrees at the most. So didn't even wet rag them. In most cases there was only the nail tips (about 1/16 - 1/8") protruding, and the ply around them was splintered out, so I don't think I really affected the nail grip any. The other candidates were where framing (16d) nails or 8d ring-shank nails used to fasten the decking down had missed or just barely caught any framing and these were providing nothing but a hazard anyway.

- Jay

Typical of the roofing nail protrusion



Typical of the framing nail protrusion



Finished product