Lap Sealant vs Eternabond Tape

If you have the cash to spare, then eternabond. If not Dicor Lap Seal. My trailer is 10 years old, still no eternabond. Lap seal has proven to be fine for me.

Hi. The proper caulk to use on the roof is "self leveling caulk". Lap sealant is used for vertical surfaces, ie around Windows, along exterior wall trim, etc.
On my roof, I installed Eternabond tape along the front and rear seams only. The rest is self leveling caulk.
I don't use Eternabond tape around roof fittings such as vents because in the event I ever need to remove or replace the vent fixtures, removal of the tape (once applied) is very difficult.
The best thing to do is clean all existing caulk areas on your roof with a hand scrub brush to remove all blackened areas. You can then better assess what caulk needs to be redone. Once the existing caulk is good and clean/dry, you can apply more self leveling caulk right on top of it.

I prefer Eternabond. Clean the roof very well and apply the tape with sufficient pressure and you are done for a LONG time.

Thanks guys.

Looks like this same stuff...

Dicor Lap Sealant

is being called lap sealant or caulk, depending on the seller, but the label calls it lap sealant. I guess it's the right stuff for the roof?

I like the idea of cleaning the old, and just reapplying where needed a little here and there. I hate to clean all of the old completely off and re-apply entirely, and I hate to spend the money on a complete Eternabond application. I like the idea of the front and rear seam thing for the tape (in future?) and self-leveling everywhere else.

This roof has three skylights, three vents, one antennae, three plumbing vents, one air conditioner and a refrigerator vent so that's a lot of work if just some touch up is perfectly adequate.

I'm still open for more thoughts and input.

If you listen to everyone's opinion on this subject, you will end up confused.
IMO self-leveling goop came into the picture due to the fact that the RV manufacturers wanted a product that would lend itself to mass production. With self-leveling stuff they can apply it very quickly, and for the least amount of material cost.
IMO for private/individual use, self-leveling goop makes no sense. There's other ways, which are more expensive and more work-intensive, which produce superior results.
HOWEVER, I'm not so much referring to rubber/membrane type roofs and materials. I only work on metal or semi-fiberglass or all fiberglass roofs.
I use 3M 4200 Adhesive/Caulk and Eternabond and Sika non-silicon products.
IN other words, some of these things you have to learn on your own. Try whatever you decide to use, and give it a few years.

All good advice above, and make sure you put something like the Maxx Air vent covers over your regular vent covers so even if the standard vent cover cracks, you won't get any water inside the rig.

Dave Pete wrote:
So here I am on the roof of our 2013 TT. That's because during a recent driving rain we got water on the carpet below a vent. Yep, two years old and the vent covers look like they are at least 10 years old and a small crack has appeared in the plastic near the crank metal support. All three vents covers getting replaced, as they all look and feel like you could stick a finger through them in about any spot.

But it was while on the roof checking this out that I ALSO see the factory applied lap sealant looking like it's getting old too. Natural expansion cracks appearing but enough questionable areas that I'm thinking I'll replace it all as well.

So here's the question. Would you clean it off and re-apply lap sealant or would you go further and apply Eternabond tape as a replacement for the lap sealant method?

Roofs need to be checked yearly....we are resealing the roof on our 2 year old Class very soon ourselves. As for the Dicor stuff there are two different products. It depends on the roof type you have. Check the dicor page and they have a video telling you which roof you have. I contacted Thor Motorhomes and they told me what kind we have (TPO). Dicor has an Ultra Sealant that you need to use a primer with for TPO roofing. Dicor also told us we not need more than 6 tubes to reseal our roof. For the cap and sides, we will probably go with something like Proflex.

I use (and have had good luck thus far with) Dicor Self-Leveling Lap Compound, applied over the old after cleaning thoroughly. Dicor Non-Sag Lap Compound is a different product for non-horizontal applications.

x2 on the MaxxAir or similar vent covers. The ability to have the vents open in the rain is priceless, as is the ability to have them open while en route. They also help keep pine needles and leaves out of the vents (although imperfectly).

The air conditioner is generally not installed using any lap sealant or other caulking; instead, there's a rubber gasket between the air conditioner base and the roof that keeps everything watertight. It's not a bad idea to occasionally remove the interior trim panel from the ceiling of the motorhome and snug the air conditioner mounting bolts a bit. They don't need to be torqued down very much, just snug.

I use Dicor self leveling for horizontal and Dicor regular for vertical uses, I check my seams regularly and if needed re-caulk, I clean the edges with dawn soap and water and a small brush, I also wipe down the seam with alcohol the apply the caulk.

I covered all the through holes and edges with Eternabond tapes. Now, I can visit my roof and look at it. I don't need to carry up cleaning solutions, a caulk gun and spreader, rags, and the tubes of sealant.