How to re-caulk RV trailer roof?

I've used the Heng's product but was not impressed. It seemed very thin to me. After 2 years it started to peel-lift. On my most recent trailer, I had a questionable area on my larger slide. After thorough cleaning, I rolled on a product I'd tried at home. It's FlexSeal Liquid. The manufacturer says it's good for EPDM roofing so I gave it a shot. It is very thick stuff, which is what I wanted and I rolled it on nice and thick. It dries into a flexible rubber. I used it 2 years ago and it still looks like new, and the slide roof doesn't leak. I'm going to go around the whole perimeter of the roof with a roller and this stuff to put a new coat of sealant on the edges. It comes in black or white. I used the white. Also comes in a paste you can put on with a putty knife if you have any open areas that need filling.
Duane

coming back?

What you are looking at is lap sealant. Here is a link to Amazon where you can buy it Linky or any RV place will have it.Do not use the caulk you have now.

I have removed old lap sealant. On a sunny day you can use a plastic putty knife and patience to get it off. Or even a hair dryer to warm it up.
Make sure the area is clean before applying the new lap sealant. Instructions can be found on the tube.

When applying a self leveling roof sealant over OEM sealant don't make a dam to stop the roof from draining. Big blobs across a area can cause pooling (lake effect) up there ...that ain't good.

If the OEM sealant isn't loose I leave it as is.
My old '97 32' 5er still has OEM sealant (80-90 percent) in most spots on the rubber roof material.

There are some good self leveling sealant brands out here for resealing those loose spots.

Not a repair. Original self leveling lap sealant such as DICOR. Unless loose its almost impossible to get off of the rubber without inflicting damage. Just wash roof with a mild detergent and let dry. Recoat all joints, fittings, and hardware with lap sealant for rubber roofs.

Use RV lapseal and just go over it making sure to cover the edges.

Don't use random non-RV caulk. I'm not sure what you mean by "thermoplastic" but if it contains silicone, you may run into an issue where nothing will stick to it. Or if it contains harsh chemicals, it could damage the rubber roofing.

I’m a Heng’s fan too. Never look for, or care about, beauty in an RV roof. Look for recent maintenance.

I use Heng's rubber roof seal. Thin, goes on like paint. No leaks. Would cover all that and make it look a lot better.