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Community and Q&A

Through-fastened metal roof issue / Standing seam option

Pat_Kiernan | Posted in General Questions on


In this post:

and in this:

Is through-fastened metal roofing a good idea?

you talk about the merits of through-fastened metal roofing. I agree on most aspects.

One issue I’ve seen on two homes I’ve lived in with through-fastened metal roofs (using screws with integral neoprene washers) is that the screws would back out over time. It got to be an annual or bi-annual ritual to get up on the roof and re-tighten the screws with a cordless drill. The installation seemed fine in both cases, with the screws going into OSB sheating.

I began to wonder if the expansion and contraction of the metal roof panels was working the screws and loosening them over time … Any thoughts?

Other than the expense, I really like standing seam roofing. I’m looking at ATAS standing seam shingle as an option:

Any comments / experience out there with this product?

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  1. GBA Editor
    Martin Holladay | | #1

    Standing-seam metal roofing is great, as long as it's installed by a roofer who knows how to minimize oil canning and waviness.

    I haven't experienced the problems you describe. It's possible that's because I usually screw into 2x4 purlins or 1-inch rough purlins that measure a full 1 inch -- not 7/16" OSB.

    Do any other GBA readers care to comment on whether or not they've had problems with roofing screws backing out?

  2. Expert Member

    There are a few reasons that fasteners pull out. Overdriving them when first installed, freeze/thaw cycles on the roof surface affecting the heads, wind working panels that flex too much between fasteners -but you're right, expansion and contraction are the most likely cause.

    The backing-out only occurs on roofs where two things are present: The diameter of the screws is too small, and the sheathing or strapping too thin. In those circumstances the force necessary to set the gasket is very close to the pull-out torque of the fastener. If the underlayment is in good shape, the solution in most cases is to use a larger diameter fastener.

    If you are tired of monkeying with the roof and decide to replace it, snap-lock panels are great alternative. A properly flashed snap-lock roof presents no potential points to leak - and none in the future.

  3. Pat_Kiernan | | #3

    Thanks Martin and Malcolm,

    It sounds like the underlying issue is probably the pull-out strength of 7/16" OSB sheathing, and the difficulty in setting the gasket without over-tightening. It seems to be a very narrow margin with OSB and the smaller diameter screws.

    Fortunately, I'm not living in either of those houses anymore. My question arose while looking at roofing material for a new home.

  4. JC72 | | #4

    +1 Malcom.

    IMO exposed fastener metal roofing for a house should be avoided because the design creates so many extra failure points that you don't have with standing seam concealed fastener metal roof. You also don't want to have to go up on the roof every couple of years to looking for loose fasteners or deteriorated washers/gaskets.

    If standing seam is cost prohibitive would opt for metal or asphalt shingles before going to exposed fastener metal roofing.

    My 2 cents

  5. rocket190 | | #5

    I've salvaged affair amount of through screwed roofing,and have definitely seen a lot of loose screws. Mostly these are screwed into 2x4 purlins. The longer the sheet length, the greater the chance of sun induced panel expansion, and wiggling screws. You can actually notice the screw holes being oblong.

  6. Pat_Kiernan | | #6


    Your noticing that the screw holes were oblong confirms my sense that the holes had gotten sloppy. I didn't have the opportunity to look at things with the panels off, so I really appreciate your observations.


    You and Malcolm have made a good case for me to find room in the budget for a roof without exposed fasteners. Thanks.

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