What Roof Coating do I use for a Flat Roof?

[martinpeter85]

I reside in a 15 year old flat roof covering 1400 sq. ft. of my house. The roof covering is a black rubber membrane.

It has never been kept up with so there is cracking and some leaking. I already went up and patched spots with a fibered roof cement, but now that it is getting decently warm I want to coat the whole thing to seal it all off.

What particular kind of coating do I use?

I read somewhere that the roof should be "sealed" every couple of years. Well this have never been sealed.

[hausdok]

Hi,

It really depends on what the membrane is. At 15 years old and without a history of very diligent care there's a good chance that the roof membrane is not worth trying to save and a new membrane would make more sense.

When you say "black rubber membrane" do you mean that the roof is actually a rubber, similar to an inner tube or is it a plasticized asphalt. Can you take some pictures - some far off shots and some close-up shots and then post them here for us to look at?

ONE TEAM - ONE FIGHT!!!

Mike

[caryseidner]

Well, if it is EPDM rubber the oils in the roof cement will breakdown the EPDM and ruin it.

I wouldn't even bother coating a 15 year old roof. While coatings will protect the surface from UV and extend the life, it won't due much for a 15 year old roof that hasn't had a well maintained coating on it for the last 15 years.

Keep patching it until you can afford to replace it.

[RamanMaan]

The white roof coating or weather resistant roof coating are best. You can select any one of them as per your requirement.

[hausdok]

Hi Cary,

I doubt if it's an EPDM membrane. When most homeowners say "rubber" and then describe the random crazing all over the cover they're usually describing a modbit membrane that's getting on in years and has never been surface-coated. I agree, petroleum-based roofing products will break it down whether it's an EPDM membrane or a modbit membrane.

RamanMaan,

The coatings aren't going to do much good if the cover is already shot. They are designed to protect the cover from the effects of UV. Once the cover starts showing all that crazing, it's saying, "Hey look! I'm getting pretty old and weathered. You need to start thinking about what you're going to replace me with and start budgeting appropriately or I'm going to leak."

In this case, it's begun to leak and he's slathering goop on the cover to try and stop the leaks. It's a bandaide. There are coatings that you could apply to the cover to seal it - hell, bedliner would form a great skin - but by the time you isolate the old cover from the product and spray that stuff on you'd properly end up with a cover that'd cost you as much if not more than a new cover of materials designed for a roof and it would still be, well.....goop.

He needs to replace the cover. If he replaces it with a new modbit cover, a granule-coated modbit cover will last longer and won't need constant re-cleaning, re-priming and re-coating with UV reflective materials. If he replaces it with an EPDM cover, he'll get equal to or better than the cover life he got out of the existing cover and he won't have to constantly clean, prime and coat it. If he replaces it with a PVC or TPO membrane it'll probably last at least as long as two of the current cover's lifespans and will only need occasional cleaning with mild detergent.

ONE TEAM - ONE FIGHT!!!

Mike