DIY curved metal roof? – need advice….
lloydovich
| Posted in General Discussion on
We are building a workshop that has a curved ‘gothic arch’ roof, and want to use metal roofing. The arch is 16′ radius to the curve. In our search for a source, we are encountering high priced pre-curved metal roofing….not a good option for us, due to the cost, and we like to do it ourselves whenever we can.
Is there no metal roofing that is flexible enough to bend on site as you install? (We are in northern MN).
Replies
Are you expecting the roofing to go perpendicular to the curve or parallel? At that radius I suspect you might be able to get some products to go perp.
bending metal roofing
Parallel to the curve fastened to purlins.
Perhaps Quonset steel? You can sometimes find it used & cheap. I don't know what radius sizes there are though.
DIY bending metal roofing
From what I can tell, it looks like even the quonset arrives on site pre-bent/curved to the customers specs. We are trying to find out if there is a metal roofing system where either we can bend the flat material on site...or, better yet.... bent as it is being installed on the roof.
Are you talking about
snap-lock / standing-seam steel roofing? If so, forget it, it will never bend cleanly to the radius you want. When that is done, it is done using a rollformer that is made to roll curved panels. Even the v-crimp roofing I have handled would not bend nicely to anything but the largest radius.
There are many brands that make steel that will bend. Unless you are looking for hidden fasteners. Try looking into a product like Fabral's Prime Rib. Any steel that has a shallow rib will bend fairly well as long as the curve isn't too sharp.
Only if your roofing has no or almost no profile
If you choose a roofing material with any signifigant profile, say PBR for example, the radiusof the top of ribs will be greater than that of the flat part of the profile. Steel has high tensile strength and won't stretch easily. If you hope to accomodate the different radii by compressing the flat part, it will probably wrinkle (cripple) rather the shrink.
If you assume that the rib height is 1 inch, your sheet length is 10 feet and your arc is approximately 35 degrees, the difference in arc length is going to be about 2/3's of an inch. So you either need to stretch the steel the makes up the top of the rib that length, compress the flat part that much or somehow split the distance between them. I suspect this is going to be tough to do in the field.
Good luck.
The rib is always the problem ... Ask Adam
Seems you're getting pretty consistent response .. the rib is the problem ... I'm doing this with and eyebrow dormer right now and my metal roofing contractor has to sub out the radius panels to a custom fabricator and will then install them as pre-formed panels ... trick as a DIYer would be to find his sub in your area ... I can tell you who it is here in South Florida but I doubt it will be of much help ...
Good Luck
Okay - what about this...various people have said that corrugated roofing (galvanized?) would work...but this is for a workshop - heated and insulated. We don't want it leaking or rusting on us either. We would be interested in hearing thoughts / opinions on that.
Corrugated roofing
If by corrugated you mean material that is the same depth across the panel, as opposed to material with a rib, a simple test by bending it to your profile should indicate whether or not it will work ... Greenhouses are typically made of currageted plastic panels and bend to a pretty tight radius ... steel won't be quite that flexible ... give it a try. As for sealing and leaks, most of the corrugated systems I'm familiar with are attached with rubber o-ring gasketed self drilling hex head screws. Ideally the o-ring makes the seal and the steel rust together uniformily (not really about the rusting part) Part of the accessory package for the corrugated roofing panels will be closure strips to help keep the weather out.
View Image
This is the type of material I would be looking at, the shallower the corrugations the better for your application and I was thinking your would select the radiused corrugations as opposed to an angular bend corrugation. I've seen this material in copper on high end houses in CO ... it patinas beautifully ...
Good Luck
Yes - the shallower corrugations, radiused corrugations as opposed to an angular bend corrugation is what we are considering.
And the idea of ordering/purchasing a sheet and trying it is something we will do before we invest in an entire roof of material.
Which brings up the question of what to look for in determining quality of material and fasteners, and overall longevity of galvanized roofing in a northern MN climate.
What features/specs would a person look for in determining that they are getting something that will last?
What is the average life of corrugated roofing in this climate, if we can find a quality product?
My gut feel is that your standard corrugated steel isn't going to bend tighter than about a 30-foot radius. You could probably coerce it tighter, but then the seams would never lay flat.
Yes - the shallower corrugations, radiused corrugations as opposed to an angular bend corrugation is what we are considering.
And the idea of ordering/purchasing a sheet and trying it is something we will do before we invest in an entire roof of material.
Which brings up the question of what to look for in determining quality of material and fasteners, and overall longevity of galvanized roofing in a northern MN climate.
What features/specs would a person look for in determining that they are getting something that will last?
What is the average life of corrugated roofing in this climate, if we can find a quality product?
Pageing Doctor Fine, Doctor Howard, Doctor Fine...
Where's Grant?
Duane?
Walter?
This is right up their alley. I'm quite certain they've posted photo tutorials in the past. At least I think I remember a barrel dormer done by Walter.
They've skeedaddled
Walter and Sphere can be reached at BreaktimeClassic
Grant over at his site or Contractor Talk maybe.
poof!
I did a search and found some of the old copper threads, to include barrel dormers. Problem is that with this latest brilliant morphing of the breaktime forum software, virtually all of the photos are gone.
Poof!
Disappeared. Just like the Old Breaktime Gang.
Oh well. So much for reminiscing. Gotta put on the tool belt and install some front porch columns. Wish me luck...
I found the breaktime classic forum and will post there as well....is there a website for "Grant over at his site or Contractor Talk maybe."?.......
http://www.grantlogancopper.com/
Be More...
Lots of replies, no real answers.
I find that when you aren't willing to shell out the money to do it the "right way" then you must be more creative. My initial thought (along with other commenters here) is that standing seam will not work without some specialized machinery. At r18' the vertical corrugated/ribbed will not work either. You can trust me on that. A horizontal corrugated/ribbed would work but looks a bit goofy.
My advice is to get creative and try to make your own metal shingles. Flanged metal diamond shingles are certainly an option.
dome-roof-copper-construction-Rutland-5.jpg
are many places to buy them but they seem easy enough to make and install. You'd probably just need some snips and a hand break at minimum. Could be copper if you can hunt down a good deal but galv. steel would be interesting or painted aluminum is abundant and reasonably priced. You could even if you wanted to use steel and have it powder coated at a local shop. Really there are a lot of options for metal shingles both material wise and dimensionally. Something for every budget.
There is a real answer
Try a commercial product called Siplast
http://www.siplast.com/IcopalUS/HC/2010/Roofing/Multi%20Ply%20SBS%20Modified%20Bitumen%20Membranes/Foil%20Surfaced%20Membrane.aspx
I installed much of this product myself on my home in Wayzata. It is a roll roofing product with a metal foil coating. The process is layered, starting with ice/water shield, then nailing on an asphalt rolled roofing and then adhering the final layer of rolled roofing with a torch, melting it to the nailed down layer. Not easy, you will end up with a few blisters from dripping hot tar but nothing that a good do-it-yourselfer should not be able to handle. The image of my house has copper, there are many other options for finishes.
Jonathan Crump, AIA