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Community and Q&A

Easiest concealed-fastener metal roofing

Jeff Cooper | Posted in Green Building Techniques on

Working alone, I will be covering the simple gable roof of my new house with steel panels attached to purlins 2′ oc without decking. I would like to use a concealed-fastener system. The Vertical Seam panels made by Metal Sales are approved for open framing, but after reading the installation manual, I have the impression they will be a pain to install, using tons of butyl tape and tube sealant in addition to quite a wide assortment of steel parts, including z-closures that have to be cut and bent on each end by hand for each of the 78 panels I will install. The anticipated difficulty and expense revived my interested in an exposed-fastener system, which Martin and others recommend, but the ones I’ve found that are approved for open framing only come in 3′ widths, which I often won’t be able to reach across as I install from below. Malcolm said in another discussion that he installs concealed-fastener steel roofing faster than he could shingles, so I’m hoping something easier than Vertical Seam exists.

Malcolm and others: Could you please recommend a specific model of concealed-fastener steel roofing that is approved for open framing and relatively easy to install?

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  1. Jeff Cooper | | #1

    Edit: strike what I said about 3' widths; I found Delta Rib and 5-V Crimp panels from Metal Sales that come in 2' widths and are approved for open framing. Recommendations for easy, concealed-fastener systems would still be much appreciated.

  2. Expert Member
    Malcolm Taylor | | #2

    I have my choice of several local roofing suppliers for what are very similar products. I'd presume most areas have at least one.

    They do go down fast. For a simple gable roof you won't need any particularly complex skills. You snap one side of the panel over the previous one and then screw down the other. The ridge can be left open using ventilated closure strips.

    I'm not sure if the panels will span 2'-0", but most manufacturers include tables (and installation details) on their websites.

  3. Jeff Cooper | | #3

    Thank you, Malcolm. Westform's Prolock is not approved for open framing; Westman doesn't say.

  4. Expert Member
    Malcolm Taylor | | #4


    From the Westform site:
    "Our products can be used in both new and old construction. We recommend installation over solid substrate. Installation over strapping is also possible. "
    They include span tables showing the gauge needed for various spacing.
    Westman steel makes a very similar product in the same gauges. Both are commonly installed over strapped roof framing. Using a solid sub-strate is a relatively recent practice. It has become more common here on the coast since our new seismic requirements came into effect.

    I not suggesting you use either of them. These types of snap-lock roofing panels are manufactured all over and I'm sure you can find a supplier closer to you. Their main virtues are ease of installation and that, apart from a few gasketted screws on trim, the fasteners are concealed.

  5. Jeff Cooper | | #5

    Thank you again, Malcolm. I had read the paragraph you quoted, but I took "strapping" to mean 2x4s or 1x4s attached to decking to create an air space such as Martin and others have recommended. Lower on the page, they seem to use "strapping" in that sense: "Existing Roof: In some cases metal roofing can go over existing roofing. For those roofs use 1x4 strapping on 16" O.C. screwed through to the rafter." I saw the load tables too, but didn't know whether they were applicable to open framing, where the panels have to be structural, unlike atop strapping with decking.

    Westform does look easier than Vertical Seam. If it's approved for open framing and affordable, it will be a good choice. I hope more recommendations will appear here, as it took reading a very long installation manual to understand what a pain the Vertical Seam is, and actual experience like yours is much more useful than a manual.

  6. Expert Member
    Malcolm Taylor | | #6

    I stated installing my own snap-lock metal roofing on projects when I got a quote of 20G for a house and found the material portion was less than half of that. Since then I've done dozens.This summer two of us put on a 4300sf roof with valleys and dormers in two weeks. The materials were around 12G, the installed quotes closer to 40. I find valleys, dormers, skylights and chimneys are more complex to flash than asphalt shingles, but gable or shed roofs are pretty straightforward.
    Good luck with your project!

  7. Brad Hardie | | #7


    Where do you live? Here in NH, there are standing seam/vertical seam installers getting a minimum of $450/square and upwards of $800+/square. Instead of hiring an installer to do the cutting, bending, and install of the standing seam - I'm getting "cut and drop" standing seam for $200/square or $2.00/sq ft.. Same metal, same equipment, same custom lengths, same custom ridge cap, etc., except we are doing the install. Even the tools are supplied! At 40+, with many valleys, hips (see farmer's porches) and shed roofs - it is an extremely reasonable cost.

    We did this recently on a fairly large outbuilding and it went great! We also used 2x4 horizontal purlins 2' O.C.. The metal is 24 gauge when installing over purlins, instead of the 26 gauge many installers use. It's a simple roof to install, as long as the first panel goes up centered, and you take your time to bend the metal at the eaves and rakes.

    Good Luck!

  8. Jeff Cooper | | #8

    I'm in AZ. What brand and model are you using, Brad? Do you have to cut and bend a z-closure for each panel?

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