Steel Roofing Guage?

Just beginning research for my inevitable shop re-roofing project. Looking for the best possible roof. What guage would you use in going plywood sheathed roof?

Glenn F.

I'd go with the 30 year warranty painted steel roof. Gauge wouldn't matter much as long as you have the 30 year warranty stuff. It costs a bit more than galvanized but is a better deal by far.

I have put on a lot of steel roofing, on houses, barns and sheds. I use 29 gauge and the tin from my supplier has a 40 year warranty on the paint. Current price is $73/square.

Why are you using plywood sheath? It will start to decay the day you put it on there. And added fire hazard. Look into the modern "insulboard" . All you want is a little noise barrier.
Are you going to install drop ceiling and blown in insulation on top of that? Then you REALLY don't want or need plywood sheathing.

(quoted from post at 18:39:23 03/31/14) Why are you using plywood sheath? It will start to decay the day you put it on there. And added fire hazard. Look into the modern "insulboard" . All you want is a little noise barrier.
Are you going to install drop ceiling and blown in insulation on top of that? Then you REALLY don't want or need plywood sheathing.

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He says he is re-roofing so I would imagine the plywood sheeting is already there, he will just be removing the old shingles and replacing it with metal.

Correct


Glenn F.

Regardless, hopefully you're aware that you shouldn't install the steel directly over the plywood. You need 2x sleepers run horizontally underneath to allow for airflow.

Where are you located and what size hail do you get? Three and four inch diameter hail stones will dent thicker steel than nickel size hail stones. Will it bother you much if the roof eventually gets dented?

question then ,, if your not supposed to put it directly on plywood,, around here contractors say they put an insulating board down then sheetmetal,,, aint no air flow there?

Am just finishing a Firestone standing seam, 50 year warranted roof on the daughter/SIL's house. It is 24 guage material. This system utilizes the black or red "Ice and Water" underlayment on top of sheeting but can be installed with the 1x2 nailers or on top of 1" styrofoam directly over existing shingles.

24 guage steel with a multiple step bonding process for the coating and coloring that maintains a 30 year guarantee against fading along with the 50 year material failure guarantee.

Those cleats in the valley are 20 gage screwed every 6" with a 3" three ribbed sealant installed on the underbelly. The ends of the panels are folded 1" over the 20 gage cleat.



The three piece ridge cap has a 1 1/2" double fold that is filled with a eurthane sealant for the top end of the panel to be inserted into before the actual top piece is slid over locking to the top flanges. The connecting sections of the ridge cap will be sealed with the eurthane sealant then rivited with stainless steel rivits on each side.



This kinda gives an idea of how the ridge cap comes into play. The "inverted J" is screwed approximately every 12" and the top of the panels are forced up into the 1 1/2" eurthane seal. The channel has slits sliced in it to allow venting of the attic.

I put this on my own house about two years ago and have not found yet a better system. The installation is correct and properly sanctioned by the Firestone manufacturing company.

Next project will be the SIL's shop.

I forgot to add it is guaranteed to 140 mph wind and guaranteed not to dent or damage with hail up to 2 1/2".