attaching corrugated roofing

[zachslc]

How can I attach corrugated roofing to osb to ensure no water will get under the metal? I was going to just put a small dab of caulk over the nails, but I'd like something more permanent and reliable. I was thinking about a sandwich of neoprene washers, but I am not sure it would be water tight. I'll also be using my framing nailer, so it might be hard to shoot a nail right through a small washer. What about marking nailing points on both sides of the roof and putting the caulk between the metal and osb? Any ideas? Thanks.

 

[Eric in NC]

self taping screws with rubber washers - there are special ones made for doing the job

 

[Indiana hens]

Metal ,with nails through it, is never a guarantee not to ever develop a leak around the nail. Woodtight screw would be better; they are usually cheaper at your local barn metal dealer. No on the nail gun! Polyurethane caulk is great to stop leaks; makes a rubber flashing. Standing seam with concealed fasteners is more reliable but expensive. I also would use screws on corrugated

 

[Muzzleblast]

Do not attach the metal directly to the osb. Attach some 1x4's to the osb and then attach the metal to the 1x4's. All the nails or screws should be in the 1x4 and not the osb.

 

[patandchickens]

What they both said. Buy the screws designed for metal roofing. Woodtite is one brand, there are others, just talk to the folks at your hardware store. They mostly have hex heads so make sure you have an appropriate driver bit. You will NOT regret using them, I promise.

(You can, or at least used to be able to, get rubber- or lead-gasketed nails for roofs, but do not use them - they will leak (thus cause rot) and do not hold the metal on near as tightly as the roofing screws. Which is especially important if you are just screwing into OSB b/c metal roofing is really better put into 2x4 strapping, for a secure attachment)

Put them through the HIGH part of the rib, not the valley. This may seem counterintuitive ('won't they hold better if I put them where the metal is right directly against the wood?") but as long as you use the right length screws they hold just as well, and if you put them in the valleys they will leak even with the neoprene gaskets. Leakage around fasteners equals rot equals things becoming unfastened, so you really want to avoid it!

Good luck, have fun,

Pat

 

[zachslc]

Ok, thanks. I should have clarifies--there are 2x4 "trusses" under the roof, and all fasteners will go into those. Can I get these screws at the regular hardware isle at lowes?

 

[Eric in NC]

At my Lowe's they are near the corrugated roofing.

 

[patandchickens]

Oh good, putting the screws into 2x4s is more secure... if you can accuately locate them under the OSB that is

Make sure to measure how long the screw will have to be, taking into account the thickness of the roofing rib as well.

Some stores have them with the fasteners, some stores have them with the corrugated roofing, some have both... if you can't find them, try finding an employee (preferably over 50, as the 18 yr olds prolly won't know what you're talking about but won't admit it). They are not a particularly uncommon item, you shouldn't have difficulty locating a source.

Good luck, have fun,

Pat

 

[zachslc]

Another thing--I was going to put a coat or marine enamel under the metal (on the osb before attaching). Is this superfluous? I have a tendency to overbuild everything.

 

[patandchickens]

In SLC I probably wouldn't bother. In the North or in a wet climate I too would paint the OSB, because of the likelihood that *some* water might eventually get between there (condensation, leakage). Can't hurt if you have spare paint and a spare half hour, and like painting things

I wouldn't bother with marine enamel though. Plain ol exterior latex is FINE.

Pat, who likes painting things, and was raised to overbuild things too, but you know, they do last longer that way