# Screws for Corrugated Metal Roofing



## joecaption (Nov 30, 2011)

Only the high spots, 20 screws per panel on a 10' panel.


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## funfool (Oct 5, 2012)

The valley. I suggest you look at the manufacturer recommendations for installing.
I know, I hate reading the manual also.
Will be screws with rubber washers you install it with.
Main concern is flat framing in proper location to screw it to and spacing of the screws, and how far apart you need to run stringers to screw to.

If you remove the old metal roofing and find it was installed over osb sheathing, is no problem, just install new metal and screw it down as suggested in the instructions.

But nailing through the ribs is a home owner diy that thought he knew what he was doing. He was wrong.


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## PPBART (Nov 11, 2011)

funfool said:


> ...installed over osb sheathing, is no problem, just install new metal and screw it down as suggested in the instructions...


No sheathing, just 1x6's on ~2' centers across rafters.


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## joecaption (Nov 30, 2011)

I went on three differant manufactures web sites that make corrigated roofing and looked at there install directions. 
All suggested fastening on the high spots not the valley.


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## PPBART (Nov 11, 2011)

Here's a link to instructions from Union Corrugating Company:

http://www.unioncorrugating.com/documents/Corrugated_Installation.pdf

See figure 1 -- puts screws in valleys at eave, on ridges for intermediate fasteners(!)


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## augie1684 (Oct 26, 2012)

*Screws in the peaks*

[I'm going to be replacing the corrugated metal roofing on my workshop as soon as the material comes in. Will be using standard 26" wide corrugated (~2.5" waves). Question is placement of the screws -- original roofing was nailed with nails in the peaks of the corrugations, but I've been told the fasteners (I'll be using screw) should go in the valleys, closer to the framing and tighter. So do I put the screws in the valleys or on the peaks?[/quote]

Go into the peaks and use longer screws with rubber washers. The washers won't last very long but are better than not using anything. And don't over tighten. Peaks over valleys because you should try to keep the fasteners away from water. Where's more water? In the valleys. Plan on going back up every couple years to re-screw down the screws due to the metal expanding and contracting. That natural effect of heating and cooling will eventually work the screws loose.


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## funfool (Oct 5, 2012)

All the metal roofing I have installed is coloured roofing on homes, it has flat spots in the valley and perfect place to fasten it. 
And I use 2 length of screws while installing it. Longer screws in the valley to fasten it to the framing, while short screws where the ridge over laps.
In a 3' wide piece, will be 3 screws in the valley holding it tight to the framing, the short screw on the overlap, I do not want to reach the framing, just tie the two pieces of metal together. So the wind can catch the lip.

My concern with screwing it on the peaks, I am using a 18 volt makita screw gun, Going to take a real light trigger finger to snug the screws with out sucking down and distorting the shape of the metal. I want to screw it to the framing in the places the metal sits flat on the framing. So short screws for the overlap, do not want to reach the framing.

Your real concern on a metal roof is the flashing. will be some that gets installed before the roof panels go down, some after.
Depending on your roof, as to what flashing you need, not uncommon to need 4 different styles of flashing, sometimes will need to have some made up to work for that job.
Just thinking, no sense in over thinking the screw pattern, your manufacturer will tell you. The key to a metal roof that does not leak is the flashing.
All of this depends on the finished look you want. 
A $300k home, it needs to look nice, A chicken coop in the back yard, a little more flexibility.


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## smalpierre (Mar 1, 2012)

R-panel roofing is screwed in the flat (valley) area. If you screw through the peak, it's got nothing backing it up, so the metal will flex. I'd screw it down into the rafters.

With the screws to fasten two panels together, you're not going to compress the peak since you're only screwing the two panels together.


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## lawrence.crush (Apr 8, 2014)

Funfool is right - follow the manufacturer's guidelines if you are at all concerned with performance or warranty coverage. Nailing the metal panels on the peaks will distort/ bend the metal around the screw. Even if you manage to attach the panels without any kind of distortion, the next windy day you have, you may start seeing warpage around the peaks and screws.


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## eclark (Jan 23, 2012)

If you want a warranty the only thing that matters is the manufacturer installation requirements. If you don't care about that then do what you feel like. Fastening through the ridges is better for keeping water out but harder to keep the metal from distorting. Fastening through the valleys is worse for water but looks prettier.


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