I roofed a couple of large residences with metal, five years ago, and they are leaking. The metal sections are pre-painted, about 3 feet wide. They are screwed together along their edges via a raised lap. The screw goes through both plys of metal and holds them together; it does not go into the wood 1×4 nailers attached perpendicular to the rafters. The screw that attaches the metal to the wood is placed in the flat part of the metal sections.
A soft gasket was placed in the lap when the roof was installed, per manufacturer’s instructions which also were followed in the whole installation
The problem seems to be that a number of the screws have become loose.They are about 1 1/4″ long, 1/8th” screws. Some have actually backed themselves out 3/4″. Others seem to be loose, their holes either rotted out or otherwise become too big.
anyone had this problem? How did you fix it?
No pros around here seem ever to have seen such a problem before.
Replies
If I understand you right, you have put fasteners in the raised lap as well as in the flat field.
I have never seen manufacturers recommend that particular detail. The ones I have used specifically prohibit any fasteners but those in the flats. I believe this is your problem. If the manufacturer did so specify, go first to them for resolution and re-imbursement.
I think the repair will now involve replacing those fasteners with
A> Longer ones that will reach teh underlying wood to hold tight. They would have to be placed very carefully to avoid compressing and distorting the rib
or
B> use the next larger diameter screw. They make a 5/16" tec screw.
Either of these options are probably also short term, but the best advice I can give, short of replacing the whole roof. If you have installed this over 1x4 furring, it is possible that you will not be able to hit wood with longer screws and that the bigger ones remain you best bet.
Excellence is its own reward!
it is the screws thru the lap that are loosening?
20 years ago I did a metal roof that the supplier recommended the detail (screws in the lap) that you mention - the fasteners supplied were gasketed sheet metal screws, not self tapping and of a larger gauge than the screws for the flats - 5/16" heads vs 1/4" for the flats, and only 3/4" long - a PITA - never got any complaints, it's not too far away, I'll check it the next time by -
I could imagine that thermal expansion/contraction could furnish the energy to hog the holes and loosen the screws - I'd call in the manufacturer to diagnose and propose a solution - fatter screws would serve for the short term, but would be subject to the same stresses -
I would have suggested the same as Piffin. Replace all the screws.
But I would go one better.
Every time that you remove a screw, squirt a blob of lexel into and around the hole. Then put in the new screw.
You get gription and seal, both in the same stone-throw.
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Quittin' Time
I agree with you and piffin, but add remove all the screws on each lap first. Carefully lift the lap and look at the rope caulking between the lap joints. I think that you will find it in pretty bad shape, at least around the lap screws.
The roll type caulking that comes with that type steel roofing is of questionable quality sometimes. I have seen it dry out and crack in as little as a year. When replaceing the lap screws with larger diameter screws the metal pulls back together but the sealant cracks even more around the area of the screw. Cleaning out the old caulking and resealing with a high quality flexible caulk will insure water doesn't wick across the lap.
Dave