Butyl tape and foam closures: "I have a quick question about installing my corrugated metal ..." - Tim Seeton (7/20/2021) | Installation

I have a quick question about installing my corrugated metal roof DIY. I searched the internet everyone tells me to use butyl tape and foam closures. But my question is why why can't I just use 2 beads of tar in between the seams. As the phone closures and butyl tape add up to be a pretty hefty expense after it's all said and done at $7 a roll respectively each item for not very much distance/ quantity. Thank you in advance,
Tim

What do they use 50 years ago when installing metal roof in between seams? I'm pretty sure foam closures weren't around.

Tim Seeton

7/20/2021

The foam closures are used to prevent debris and weather from getting beneath the ridge cap and then getting beneath the panels. You definitely need some sort of closure for the voids created by the flats of the pans at the ridge. You could perhaps also do it with metal Z Cleat custom-formed between the ribs, or by "breadpanning" the ends of the panels. These are both pretty difficult with trapezoidal ribs so most folks opt for the foam closures.

Foam closures at the eave serve a similar purpose but I'd say are generally less important.

As far as sealant in the overlaps, different panels will have different designs and may or may not require that. Some may also require it but only on lower pitches. Tar will not have the life expectancy that the butyl tapes and sealants will, and also will not stand up to thermal movement of the system.

I know you're hoping for an answer here but due to the myriad of panel designs that exists, I really must refer you back to the manufacturer of the panel you're installing for their instruction and direction.

Todd Miller
Isaiah Industries, Inc.

7/21/2021

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