steel roofing question
Printed From: Unofficial Allis
Category: Other Topics
Forum Name: Shops, Barns, Varmints, and Trucks
Forum Description: anything you want to talk about except politics
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=210594
Printed Date: 02 Apr 2026 at 1:41pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: steel roofing question
Posted By: jaybmiller
Subject: steel roofing question
Date Posted: 01 Apr 2026 at 6:46am
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Curious...
Is it 'normal practice' to install steel roofing DIRECTLY on to shingled roofs ?
Amish(?) crew doing my old shop, left the shingles on, strapped the north side, installed tin, south side NO strapping, went direct onto the shingles.
FWIW Job costing $12K, I'm thinking $4500 in tin and 1x4x16 boards, 3 day+-.
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Replies:
Posted By: DMiller
Date Posted: 01 Apr 2026 at 7:02am
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Not ever seen Tin installed on Nailers over Shingles. EVER. Most here will strip a roof add a Roofing Sheathing Cover(Ours has Titanium paper) then Purlins and finally Tin. On a strip off Complete Rebuild to afford for better Snow Load, ours has 3/4" T&G Sheathing then the paper and Tin directly screwed to Sheathing.
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Posted By: jaybmiller
Date Posted: 01 Apr 2026 at 7:33am
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the roof has ,from top layer to bottom layer...
new steel tin 3 tab shingles(south side 10 years old,on top of say 30 year old , north 30 year old) 5/8" t+g plywood original aluminum roofing on 3x4 purlins(girts ?), trusses 12' on center .
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Posted By: Dave in PA
Date Posted: 01 Apr 2026 at 7:38am
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My thoughts on this. The shingles are bad, get them gone, remove! As for tin directly on the shingles, you can answer this yourself. Is it a good idea, to lay a painted metal sheet, screwed down, when it is going to expand and contract due to the change in temp. directly on a coarse grit shingle acting exactly like a piece of sandpaper?? Not in my opinion.
dave
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Posted By: DMiller
Date Posted: 01 Apr 2026 at 8:35am
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Shingles needed Offed. Plain and Simple. Girts Wrap a Building Purlins top a Roof. Per a Builder here.
https://strucalc.com/blog/industry/girts-vs-purlins/" rel="nofollow - Girts vs. Purlins: Unraveling the Key Differences | StruCalc
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Posted By: DanWi
Date Posted: 01 Apr 2026 at 9:00am
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Strip it with 2x4 over shingles. They will have a little control over getting those 2x4 nailed or screwed solid. Then the screws in the tin will have less chance of ever coming loose. Taking the old shingles off probably doubles the price of the job.
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Posted By: jaybmiller
Date Posted: 01 Apr 2026 at 9:40am
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Nice to see we ALL think alike !
'contractor' is cheap....
I'd have got rid of all the shingles( easy 4/12 pitch),strapped, tinned but sadly no longer MY shop.
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Posted By: WF owner
Date Posted: 02 Apr 2026 at 7:48am
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It's a very common practice in our area to strip and apply steel over shingles. Much less expensive, not only for labor, but a lot of the old shingles have asbestos in them.
When I changed from shingles to steel on our house (2009), the contractor recommended not removing the shingles, but I insisted on it. It was a huge, terrible mess, but I wanted to see what kind of shape the roof boards on old house (built in the late 1800's) were. Surprisingly, they replaced only one board and that was because of a weak spot at a huge knot in the board.
It should last me the rest of my life.
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Posted By: jaybmiller
Date Posted: 02 Apr 2026 at 9:06am
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well it's up and you can easily see the DIP in the roof where the truss busted. Too bad it wasn't on the north side. oh well.....
when Hy-Grade did my house in 2004, they left the GOOD shingles on, strapped with 2x4 vertically, then 1x4 horizontally, giving GREAT airflow.. so far 22 years ...dang time flies !
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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)
Never burn your bridges, unless you can walk on water
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Posted By: Allis dave
Date Posted: 02 Apr 2026 at 10:28am
It's common here to put horizontal 2x4's over the shingles and put new metal over that.
I've seen them do the same for pole barn roofs too. Put 2/4's over existing metal, then put on new metal.
I paid extra to strip the old shingles off my house before putton on metal.
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Posted By: Ray54
Date Posted: 02 Apr 2026 at 11:51am
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There are lot of older metal roofs on top of old singles out here. I don't remember any that don't have 2x4 nailers on top of the singles. But the old timers really knew how to pinch a penny so I would guess there are some.
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