Rusty nails

Whist tearing off the roof, I’ve found some interesting things. The plywood looks to be in fairly good shape. The tar paper is still on as I’m using that to spot nails easier. I’m pulling the ones I find that were used for the shingles. Lucky me, the person who put the roof on used roofing nails instead of staples to hold down the tar paper. SO that means, there’s about 200 lbs of nails on the roof.

I’m leaving the ones that had the tar paper as they’re driven flush. Anyway, I’ve got pictures of a sample of the nails I’ve found.

I’m going to be replacing the plywood near the vents anyway. Any thoughts on the nails? From what I could tell, there were no nail lines on the old shingles, and the installer nailed where ever the hell the nail landed…there was no rhyme or reason to the spots he picked. They tended to be up high on the shingle and they were all for the most part covered.

Anyway, the top ones are really bad, there are about 10% of the nails are in this bad of shape. The middle ones are the majority, probably 75-80% while the bottom one is mainly found on the edges.

I believe that the majority of them that are rusted on the bottom are from a high humidity attic, is this correct? The really bad ones were found mostly at the eves and around the vent stacks. I’m guessing ice damning and leaks by the vents. The plywood doesn’t look water damaged though, at least not what I would expect.



throw the nails away and put a new roof on.


[quote=“gweedo”]throw the nails away and put a new roof on.


Well, thank you Captain Obvious!

The problem is that the deck is a low slope and probably should’t have shingles on it. I won’t speculate on the specifics of nail deterioration as it could be from a number of things.

It’s a 4/12 slope, so it’s not technically a low slope, but damn close.

Yeah, 3-4/12 is gray are IMO. If I put shingles on it I’d cover the entire deck in ice barrier and double felt. It’s rough because it will have snow sitting on it in most cases.


Ice damming will not rust nails like that.

For a galvinized nail to rust it needs constant moisture.

You do not need Storm Guard on your whole roof. Shingles are fine on your roof with nothing special done.

If it is from humnidity, then put in a power vent with a humidistat.

I ended up replacing 4 sheets of plywood today, it took a lot longer than I expected. I’ll post some pics tomorrow morning, the undersides were horrible looking. It looks like at one area on the ridge I had a leak that was slowly leaking. None of the insulation was damaged, but there was some ugly plywood. For the most part though, it was still solid enough to walk on. I just wanted to get rid of the moldy areas.

While I had the sheets off, I took the time to add some extra insulation to areas of the roof I couldn’t reach. I left plenty of room for air to move around from the soffit to the ridge area…over 6" of space so I shouldn’t have any problems with air flow.

4/12 is fine with only doing ice & water 24" inside of the warm wall. all other roofing practices are going to be normal in your situation.

Did you diagnose why water was getting to the nails? I’d feel uncomfortable replacing a roof without understanding why the water got there in the first place.

Has anyone stop and think the roofer might have used old nails ??

remember how some leave the nails for weeks in a bucket before using :expressionless:

I’m not above reusing nails… but certainly not ones that are thinned or corroded!

QRFL in with the “ahhh, so… hmmmm.”

I know get 1 gallon of gas and a pack of matches. Who will care if the damn nails are rusty. For god sake it had a leak. DO the roof and get on with life. Thats my thoughts on this.

GTP must have gotten an extra helping of “Cranky - O’s” this morning.

It’s one thing if he had a leak in one particular area as evidenced by bad nails & decking over the course of 1, maybe 2 sheets of decking… but if the nails were bad all over, then yeah - it’s something to address for future concerns.

captian obvious here,
if we look at the responces of gweedo and gtp1003,
we will find that,
they are very simular.

so you are now going to put your roof on.

roof doesnt look steep enough to me.
you say its a 4/12 , but theres no way that pipe
is comin out of a 4/12. the angles wrong.
pipe may be crooked.
dought it.

so again what is you slope?

if you have less than a good 3/12 slope
i would not advise shingles.
if you have a 3/12 ( look more like a 1.5/12),
make sure u use 3 tab shingles.


The angle I took the picture from is deceiving.

I’ve replaced 5 sheets of sheathing that were really nasty on the underside and have finished the back of the roof. I ran I&W to 5 ft inside the interior wall on the back and will do a similar treatment to the front.

I stripped the front and found a similar area and will be removing and replacing that today. The first foot or so of deck along the whole eave edge is gone, so I’ll also be patching in a 2 ft section the whole distance. Hopefully the rafter ends are in decent shape, I think they are but we’ll see.

Better check that ventilation system. Thoroughly.
Also could they have been old nails from a previous roof? Not re-used, but simply left in place .
Either way, check the ventilation system. Thoroughly.

Yeah, I’m sure they’re not. The house is 25 years old and I’ve had it 16 of those years. I have some threads on this board and another about venting, I’ve beat that horse dead. I’ve opened things up to get to a ventilation level of approx 125:1 to make sure there’s plenty of air movement.

The front of the house was really screwed, I ended up replacing a bunch of plywood and had to add 5 lbs of 8d ring shank galv nails to tighten the remaining plywood back up. The nails were popping on many sheets, so I pounded them down and added the ring shank nails.

When you deal with plywood issues, everything on the job seems to slow down. :x