Nailing Tin Roof (Dumb Question)

[Big Bri]

The best way is driving screws with rubber washers on the ridges if you use 24 ga. corrugated metal or thicker. Most box stores sell corrugated that is about 32 ga. and you can not tighten a screw tight enough to compress the washer without denting the metal unless you use the corrugated filler boards under it.

This very thin metal needs more screws to hold it down, more purlins plus the corrugated strips that are not needed with 24 ga. so if you go to a metal supplier and get the 24 ga. you may wind up getting a much better roof for just a very small amount of extra cost.

Many times I have found stained 24 ga. at metal suppliers for the same price as new light gauge at the box stores.

P.S. New commercial metal buildings use R-panels that are screwed down on the flat. Different designs, different rules.

oh, learned some thing new. thanks

 

[tallyho8]

My metal supplier recommends screwing their 26 ga. corrugated in the valley but I believe that this is because it is too thin to screw it tight on the ridges. I still would screw down 24 ga. on the ridges though this involves using longer screws.

 

[studor]

I have used a fair amount of metal roofing made by Ideal. In their instruction sheet the screws go on the ridges where the two sheets overlap .. so you are going through two layers of metal and therefore harder to compress (and harder to put the screw in ) Screws go in the valley if you are using it as siding (cause the valley is where the two pieces overlap) and the valley is the same as the ridge for roofing but reversed Putting screws in the valley on roofing seems counter intuitive somehow but maybe I just haven't seen the material where it would make sense. On long runs you can run a bead of caulking down the ridge on the bottom piece, then when you lay the next piece on top you have a raised waterproof seam -- JMHO

 

[studor]

My metal supplier recommends screwing their 26 ga. corrugated in the valley

It looks like that stuff does not even completely overlap even once on the ridge --most of the stuff I have ever used completely overlaps at the ridge and some designs are meant to create two overlapping ridges -- whose stuff is that? -- Is it an "inexpensive" brand?

 

[Lineman North Florida]

I built a 32x60 barn and screwed all the tin in the flat, have not had a leak yet, hope my luck holds out, around here about 90% of tin roofs are screwed in the flat, must be a regional thing, my roof is about 4 years old seems like if screwing in the flat did'nt work well I would have already had a problem.

 

[Tig]

I've done a few steel buildings and roofs in my day. Manufacturer's instruction has always been screw the ridge on the roof. This allows the screw to give a bit with the metal expansion as the temperature changes. Otherwise the metal will work the screw hole larger as the metal shrinks and expands.
The ridge also keeps the screw head high and dry.
Check with your supplier.

 

[tallyho8]

It looks like that stuff does not even completely overlap even once on the ridge --most of the stuff I have ever used completely overlaps at the ridge and some designs are meant to create two overlapping ridges -- whose stuff is that? -- Is it an "inexpensive" brand?

If you read their instructions on "Lapping" you will see that they recommend lapping 2 corrogations on roofing and one corrogation when it is used for siding. I have never seen any corrogated metal with different instructions.

If you expand the jpg after you open it you can read it much better.

 

[studor]

Sorry Tallyho -- I was just looking at the screw diagram showing overlap not the lapping instructions -- course if you have to overlap it too much, as you said buy the thicker stuff and only overlap it once with caulking in the overlap Still not sure of the logic of putting a hole in the part that most of the water flow is on .

 

[Big Bri]

My metal supplier recommends screwing their 26 ga. corrugated in the valley but I believe that this is because it is too thin to screw it tight on the ridges. I still would screw down 24 ga. on the ridges though this involves using longer screws.

that jpeg showes in the valley on ribbed roofing. i really thought that was the way to do it. i think if you do it in the ridge you will dent the ridge, and not only will it look bad but it will also make it more prone to leak. the only time i have ever put a screw in the ridge was on the lap and that screw did not go into the wood. speaking of wood you do know not to use treated wood where it will touch the metal.

 

[SuperDuty335]

Nailing or screwing through the flat works just fine until the washer disintegrates and every screw hole leaks. I have a building that was built by someone else with the exact problem. I always attach through the ridge.