Roof Material?

[David Guilbault]

I see different products for sealing, patching, refurbishing an RV roof. Some are for TPO or EPDM or other some such acronyms. I have no idea what any of them mean. What is the material on a GMC motorhome roof? And what roof products should I seek and which should I avoid? Thanks all. David.

 

[LQQKatJon]

Roof is aluminum. Sides are aluminum. Front and rear ends are SMC.

there are many opinions as to what really works sealing seams, and after owning a GMC for 9 years I cannot offer an opinion. The process of sealing also varies on how you go about that project.

i have my seams sealed now with wurth Bond and seal, but still have some funny leaks when it is sitting and raining just right.

i an looking at the dicor lap sealant for vertical use next.

 

[Matt Colie]

Just don't use any non-paintable silicon based RTV. In the future, you may want to paint the roof and that stuff will give you fits.

Matt

 

[pvfjr]

I see different products for sealing, patching, refurbishing an RV roof. Some are for TPO or EPDM or other some such acronyms. I have no idea what any of them mean. What is the material on a GMC motorhome roof? And what roof products should I seek and which should I avoid? Thanks all. David.

EPDM is a synthetic rubber compound that is used on conventional motorhomes. It's black, and what you'd normally think of when you hear the term "rubber" these days. Lots of bungee cords are made of it as well, and you might see it stamped into them.

TPO is a polyolefin (same material as heat shrink tubing). It's just another kind of membrane roofing.

These types of roofs often have a coating that keeps them from aging so poorly, and also reduces the emissivity (read: keeps it from getting so hot in the sun). These coatings can act as a sealer as well. They often need to be recoated every few years as they start to wear off.

With the GMC roof being aluminum, you can add fresh paint to the roof, but it just serves as an oxidation prevention at that point.

 

[tmsnyder]

EDPM can be had in white as well, two part rubber that you paint on to a clean surface. I have done this on a vintage travel trailer and it's good stuff. IIRC the brand I used was Liquid Roof EDPM

On the gmc however, I'm just going to use Dicor lap sealant to seal the penetrations and joint in the roof.

 

[GatsbysCruiser]

If sealing the entire roof you might be able to help yourself with heat diversion.
I am a fan of Kool Seal for heat reflection.
But with the GMC you have that curved roof where it crests over to the top. You don't want Kool Seal visible.
The reason is because Kool Seal cure like a flat paint and it gets dirty in the weather and has to be washed once ever year or two.
Fill in the seams with a good caulking or sealant you trust, then put the KoolSeal over the top of the GMC, but don't go over the crest where it will be seen. That's over half of the roof that would collect heat to the inside of the coach. There will be a difference.
where the seams are, they suggest a cloth that you apply 1/4 to 1/2 inch over the sides of the seam, then dab with Kool Seal till it is saturated. After a couple applications, it should look like a normal application of sealant, not cloth.
I had Kool Seal on an old RV many years back and after about 15 years that roof was still tight and drip free. This includes all the things that poke through the roof, vents, stancheons, around the Air con, all dry. That says something.
The heat reflectivity is a plus.
So if you can see the roof from the ground, don't start applying Kool Seal till over the crest where it cannot be seen.

 

[Matt Colie]

As our coach is a Glacier and every real glacier I have seen was white on top, I think I would like it just like that.
I have considered painting the roof white in any case, but if this material is better at cool than white paint, it would have a real advantage.
Matt

 

[GatsbysCruiser]

Yes its way better than white paint.
The rv I put the Kool Seal on had a white roof, and it would get hot.
After I put the Kool Seal on, it was cool to the touch on the under side. Big difference.
Kool Seal is the product I used but there are others out there, all white, that will
reflect the heat.
Anything that helps keep the heat out is a good thing.
Next are the windows, LOL.
By the way..........
You know those silver sun shades you put on the dash to keep the sun out?????
I had one and it got so hot it cracked the expensive windshield.
No more.
I made a shade from that material used on decks, not water proof but blocks 70% of the
heat, lays on top of the glas on the outside..
more good ideas, LOL.