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Metal roof retrofit (membrane)

Metal roof retrofit (membrane)

Metal roof retrofit (membrane)

I have a small size metal building with a metal roof full of leaks. The roof is a 25yo metal roof with some air wind extractors here and there. The roof needs repair, but I wish it to be a cost effective and not so durable solution, as in 4-5 years the building may be demolished. What solutions do I have? I was thinking on a EPDM membrane simply over the metal sheet, as I'm told this membrane lasts only 5 years.

Any comment is appreciated.

RE: Metal roof retrofit (membrane)

If it's a standing seam roof, the membrane might be hard to keep adhered. Plus if the roof is corrugated, you'll need to provide an underlayment.
For five years, can't you spray on a roof? I found a website for a spray polyurethane roof that looks like it's right up your alley.

RE: Metal roof retrofit (membrane)

An adhesive roofing underlayment product such as Grace Ice & Water Shield or one of the several others available may work. I put down a similar product on the roof of my house and didn't get around to putting the roofing on until a year later. I wouldn't recommend letting it go much more than that without putting something over it, though. An elastomeric roof coating, the liquid rubber stuff marketed mostly for trailer house roofs, would work to protect it and should get you past the 5 year mark, but maybe not too far beyond that.

If the holes are small (less than about a 1/4") the elastomeric coating could probably go directly on the metal roof if you prep the surface with something that will break the surface of the existing paint so that the elastomeric can bond better.

Additional note on the adhesive underlayment: Unroll it and let the sun get it hot before you stretch it out and stick it down.

RE: Metal roof retrofit (membrane)

Use a fluid applied membrane. It will conform to the shapes and will give you a few years of serviceability. Tremco, Firestone, and GAF all have good quality products for this.

RE: Metal roof retrofit (membrane)

Hello guys, thanks for the ideas.

The metal sheets are corrugated, texture is galvanized (unpainted). Do you know if that's a good substrate for the liquid membrane? As I'm seeing on videos this is essentially a more elastic paint coating.

Another option I'm considering is placing a new metal roof over the old one.


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