Metal roof installation advice

[shvl73]

All I can say is that I gave you my actual experience. The screws (actaully were not self taping... my mistake... , but had pointy ends) were installed on the flats and on the ridges only at edges. They pulled out by the hundreds... but only after 10+ years, beyond warranty range. They did have rubber washers under them but since I didn't do the installation, I can't tell you if they were tightened properly or not. When they do pull out, water rushes in. Anybody who has a permanent solution for my current problem... I'm listening.

I knew there were differing and strong opinions when I first posted.

Yes, Eddie, I seem to recall that the roofs in Latin America were the corrugated type, no flats.

Check out this company: SFS intec Weather Gard®: Products for the metal building industry

They are a supplier to the metal roofing industry and have larger sized screws that may be used to replace those that have pulled out. If you have a metal distibuter in your area that deals mostly with the pros, they should be able to order them for you. If you can't find them, pm me.

 

[texasjohn]

Thanks, Shvl73! They really do have lots of fasteners... I gotta read carefully, get out micrometer, measure current screws, etc..... good input... will see if I can locate locally... I do have a Mueller Building supplier locally... and purchased a building from them last year.. so have a lead there.

 

[tallyho8]

I'm not sure if I understand this properly, but I believe that you are saying that you are screwing the metal down to 1X4s. If this is correct, 1x4s are not strong enough to hold the metal down or thick enough to hold the screws securely. I just finished a small metal building right before Katrina and had the metal screwed down to 2x4s and I had no damage to this building. If I had used 1x4s, my roof would be in the next town right now. Over 50 years ago, they used to build many garages in this area with corrugated metal roofs and nail the metal to 1x6s but they put the 1x6s about 4 inches apart. They used leadhead nails that went completely through the 1x6s and stuck out about 1/2" and always worked loose after a few years. Then you could look at the roof while it was raining and see the water running through the 1x6 and down the end of the nail and dripping.

They didn't have the corrugated wood that went under the metal to hold up the ridges while nailing back then but they used 24 guage metal that you could seal a leadhead nail with without bending the corrugation. You could not do this with modern 29 guage metal. I feel that 29 guage is fine for walls but I would reccommend 26 guage for a roof.

I notice you have your roof about finished now so this advice may not help you but it may help the next person who reads this post.

 

[shvl73]

I'm not sure if I understand this properly, but I believe that you are saying that you are screwing the metal down to 1X4s. If this is correct, 1x4s are not strong enough to hold the metal down or thick enough to hold the screws securely. I just finished a small metal building right before Katrina and had the metal screwed down to 2x4s and I had no damage to this building. If I had used 1x4s, my roof would be in the next town right now. Over 50 years ago, they used to build many garages in this area with corrugated metal roofs and nail the metal to 1x6s but they put the 1x6s about 4 inches apart. They used leadhead nails that went completely through the 1x6s and stuck out about 1/2" and always worked loose after a few years. Then you could look at the roof while it was raining and see the water running through the 1x6 and down the end of the nail and dripping.

They didn't have the corrugated wood that went under the metal to hold up the ridges while nailing back then but they used 24 guage metal that you could seal a leadhead nail with without bending the corrugation. You could not do this with modern 29 guage metal. I feel that 29 guage is fine for walls but I would reccommend 26 guage for a roof.

I notice you have your roof about finished now so this advice may not help you but it may help the next person who reads this post.

Maybe in high wind applications but, 29ga. has been used for years and 1" screws installed in 1" purlins seems to work well. Putting in enough screws and not skipping some, as we've seen suggested here, and double screwing the eave as shown in the installation guide is the way to go. I do think the 1" screws are easier to strip out and that 1-1/2" installed in 2x KD purlins might be easier for some.

 

[weldingisfun]

One more opinion on how to fasten a metal roof. This is the outfit that I bought metal from for my pole barn.
Installation information for metal roofing and siding - Metal Roofing Wholesalers.com

 

[smiley]

Now that we have all conflicting opinions on fastening, I'll ask another question.
Years ago you could buy panels that were flat on the upper half and had the corrugations stamped in on the lower half, to use when adding a shed roof to the side of a building. Also available were ridge caps with the corrugations on both sides to seal the peak tightly. Nowdays all that seems to be available are foam strips to seal under flashing put against the side of the building or over the peak.
My problem is; I need to put a new roof on my house that changes pitch at the porch and has a dormer that needs to be flashed like a shed roof. It certainly doesn't seem that those foam seals would be adequate to prevent water from backing under the minimal overlap at the pitch change and dormer especialy if there's any ice backup in the spring. It also seems that a hard driving rainstorm would force water through these strips regardless if they're on the dormer or peak.
Any thoughts on this will be appreciated.
Thanks,
Smiley

 

[Roto]

Around here you will see the same metal roofing material done both ways. The manufacturer recommends in the ribs up here but you still see them installed both ways. I think its easier for contractors to go on the flats and thats why they do it but the preferred way is in the ribs according to manufacterer. I am building a steel building myself and am trying to figure out which way to go. havent decided yet but i wanted to put it on 3/4" OSB on the roof do you think that will hold it? Another thing is if your going on the rib you cant tighten anyway because you will squat it so its not like you can strip out the screw.

Mike

 

[tallyho8]

Another thing is if your going on the rib you cant tighten anyway because you will squat it so its not like you can strip out the screw.
Mike

This is the problem with screwing to the ribs instead of the flat. You can not get the screws tight enough on 29 guage metal to seal it from leaking without squashing the rib. On 26 guage metal you can just barely get it tight enough without squashing the rib. My manufacturer reccommends screwing corrugated through the high part and screwing r-panels through the flat. Attached are copies of the manufacturers instructions.

 

[tallyho8]

Maybe in high wind applications but, 29ga. has been used for years and 1" screws installed in 1" purlins seems to work well. Putting in enough screws and not skipping some, as we've seen suggested here, and double screwing the eave as shown in the installation guide is the way to go. I do think the 1" screws are easier to strip out and that 1-1/2" installed in 2x KD purlins might be easier for some.

Our building code does not allow 1x4s to be used for purlins nor does it allow 29 guage to be used for roofs. He is using 1x4s 12 inches apart instead of 2x4s 24 inches apart. This means twice as many screws for the same strength and twice as many places to leak in the future. 29 guage also requires 50% more screws than 26 guage for the same strength meaning 50% more places to leak in the future.

 

[EddieWalker]

Tally,

Great instructions on fastening metal panels!!!! You know the saying, a picture is worth a thousand words. It's true with your post for sure!!!

Eddie