Hard epoxy on roof?

bob57434 wrote:

My main concern is that it's brittle and doesn't flex very much.

You answered your own question.

What will happen if you put a non-flex sealant on the roof?

As a short term fix I sprayed some automotive underbody sealant on the cracks, meant to prevent rust, etc. on the undersides of cars. Kind of an asphalt smelling, heavy black sealant. Not sure if that was a great idea but it seems to have sealed pretty well. Hopefully there won't be any unexpected chemical reactions...

Welcome to the forum bob57434.

Can you tell us a little about the RV? Did you get it recently or have you had it a couple years?

It sounds like someone coated the roof but, didn't clean it properly before applying the coating.
There are recommended coatings for RV roofs. Automotive under body sealant isn't one of them. You shouldn't use anything containing petroleum, it can damage the rubber.
I wouldn't use the floor epoxy. There are truck bed liner type materials used for RV roofs.

For repairing rips or tears in the rubber, Eternabond is an excellent product.

Also, Dicor Lap Sealant for the areas Eternabond is difficult to apply.

bob57434 wrote:
What will happen if you put a non-flex sealant on the roof?

Seriously?

A travel trailer is one big bouncing, flexing, twisting and vibrating box on wheels.

Any non-flex sealant won't last a week of sunny days and cool nights....never mind towing it anywhere.

There are many CORRECT roof membrane repair and sealant products available for your RV.

Thanks for the response. Shoot I hope that undercoating doesn't cause problems.

I bought it about 6 months ago, it's only been in a few big rainstorms but after one of them there was a wet spot on the floor. It was strange because there was no dampness or water marks on the ceiling or walls and I couldn't find the source of the leak. It wasn't parked on very level ground so I'm hoping that might have somehow had something to do with it.

Thanks nobby

IMHO, a very bad idea. That unit will twist and bend more than you realize I am fairly sure the epoxy would crack. That is why most use EPDM, because it can flex & stretch.

bob57434 wrote:
As a short term fix I sprayed some automotive underbody sealant on the cracks, meant to prevent rust, etc. on the undersides of cars. Kind of an asphalt smelling, heavy black sealant. Not sure if that was a great idea but it seems to have sealed pretty well. Hopefully there won't be any unexpected chemical reactions...

Petroleum based products are a very bad idea on a rubber roof. That white product (dicor sealant) that is soft is the correct thing to use .

Like nobody said there are correct products to use. Petroleum based products will dissolve the rubber membrane requiring the replacement of the roof.

Garage floor sealant on an RV roof is a very bad plan.