Which sealant is best for roof leaks?

Lin · April 28, 2013, 01:25:00 PM

I bought a quart of Elixir Plas-T-Coat some years ago for general roof stuff. I have used it on seams and around roof penetrations. It is a brush on product that is much thicker than regular roof coatings. I do not know about Pro/Flex but assume it is something similar.

When I bought the stuff on the recommendation of an RV repair place, they told me that the can would last indefinitely if I put a bit of water in it after finishing a use. That's what I have done, and it was still good the last time I used it about a year ago. It is not water soluble, so the next time you use it, you just drain the water and your ready.

Jnbroadbent · April 28, 2013, 05:47:19 PM

You want to use a commercial grade roof sealant. The stuff I've got is Acrylic Urethane. It's made to seal roofs, move with the material (expansion/contraction) Paintable etc etc. They make it in white and it's paintable. Remove old caulk (theres some caulk remover stuff that works well, I prefer a sharp/thick putty knife), use some sand paper to clean the surface then mineral spirits. Perfect adhesion.

Then you should probably seal the WHOLE roof with a elastomaric coating (Kool Seal or something from home depot) Typically $20/gal but 5 gals are around $70. It seals and insulates. They even make a thick version that you slop on to cover bigger cracks/holes. Stuff has a 10 year warranty against leaks.

Seangie · April 28, 2013, 07:09:38 PM

Brian,

Someone from this board recommended to me CR Laurence 33S BL (Black) or C (Clear) and thats what I have been using. Its been on the bus for about 10-12 months and it holds really well. No cracks and is very flexible. Not hard to work with. Easy to wipe with towels.

I could not find it anywhere local and had to order it online.
http://www.crlaurence.com/crlapps/showline/offerpage.aspx?Productid=1036&GroupID=560&History=39324:330:511:524&ModelID=560

-Sean
www.herdofturtles.org

belfert · April 28, 2013, 07:13:18 PM

I don't know if I want to do a roof coating or not. I've read lots of stories of the roof being hard to keep clean after putting that stuff on. My bus is stored under trees and it hard to keep the roof clean as it is. The roof paint is not in good shape now as the clear coat is coming off all over.

TomC · April 28, 2013, 09:28:58 PM

Polyurethane and latex on the roof will dry out and turn to dust (on my truck conversion, they used polyurethane sealant on the roof, and after just 3 years, was leaking. I wire brushed it off the resealed with outside gutter silicone). I used silicone on my bus around my vents. That was 18 years ago and it is still rubbery and no leaks. Exterior grade of silicone (the type that smells) is still the best sealant. Good Luck, TomC

OneLapper · April 29, 2013, 11:57:40 AM

I used the 3M flexible seam sealer a few years ago. It was really difficult to be neat with it. I end up using my finger to apply it. The warmer the better. It fixed every leak and its paintable. I painted over it with the white rubber roof paint and done! No leaks, looks good, great product. Not cheap though. $44 for a 1/4 gallon.

Rick 74 MC-8 · April 30, 2013, 05:59:04 AM

I used a block foundation sealer on mine It was blue when applied but its paintable. I painted gloss white. Very similar to the stuff that you dip tools in for rubberized handle great stuff. Found it at a big box store Five plus years holding up great

Rick

belfert · April 30, 2013, 07:45:35 AM

There are a lot of options on roof sealing. I think I'm going to try the stuff Clifford recommended. I am placing an order tomorrow with Tweety's so I'll add the sealer to my order. Will that ProFlex sealer work around my Transspec roof hatches? The hatch frame is held down by screws going down into the steel framework of the roof. The screws weren't really sealed at all when I got the bus and I'm sure they were leaking.

Will chip brushes work with the ProFlex sealer or do I need to step up to cheap brushes with plastic bristles? I have a whole box of chip brushes I bought some years ago.

TomsToy · May 01, 2013, 07:44:34 PM

This is another one you might try, it even mentions trucks and buses in the spec sheet.

http://www.tremcosealants.com/products/trempro-635.aspx

HTH
TomsToy

belfert · May 02, 2013, 02:16:14 PM

I ordered the ProFlex RV sealer. Can I use chip brushes with this stuff?

FloridaCliff · May 02, 2013, 05:31:24 PM

Quote from: OneLapper on April 29, 2013, 11:57:40 AM
I used the 3M flexible seam sealer a few years ago. It was really difficult to be neat with it. I end up using my finger to apply it. The warmer the better. It fixed every leak and its paintable. I painted over it with the white rubber roof paint and done! No leaks, looks good, great product. Not cheap though. $44 for a 1/4 gallon.

OneLapper,

Also used the seam sealer on mine, hard to believe 6 years ago (2nd post in thread) and it has held up great, no leaks.

Knowing it has no adhesive issues with paint is a big plus.

Cliff