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theotherbart's avatar
theotherbart
Explorer
Nov 03, 2013

Roof repair and renewal

Looking at the roof of my 2000 Thor 21RB Class C, there's significant cracking in all of the caulked seams and the roof surface itself looks a little worn. I'd like to redo it in the spring but I wanted some input into the process. This is our first RV, but I'm fairly handy. I want a reliable system that will last, but at the same time it doesn't make sense spending more money than necessary on a relatively old rig. So here's what I had in mind:

Eternabond tape over all of the seams and around all of the penetrations (antenna, vents, etc.). But which flavor of Eternabond? Their website has many options and the differences aren't clear to me.

Then recoat the entire roof. But with what? The literature I have on this model says it's a "rubberized" roof, but doesn't specify the actual material.

The other big question mark is a "soft" area around one of the plumbing vents. Obviously there's been a failure there that has let some water in, but not enough to show any signs of leakage inside the motorhome. I have no idea how to even begin approaching that repair. I know it isn't ideal, but what happens if I just seal the seam with the tape, recoat the roof, and leave it be? If I do need to cut into it and repair, what does that process look like?
Class C

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  • myway2rv's avatar
    myway2rv
    Explorer
    Nov 04, 2013
    I used this Brushable Sealant a few weeks ago to re-seal all the cracked caulking. One quart covered all the joints and it seems to have stopped my leak. Real easy to apply. Just clean the old caulk with denatured alcohol and glop it on with a small brush. It has the consistency of honey and sticks to old caulk, plastic roof, whatever.
  • ScottnSherrie's avatar
    ScottnSherrie
    Explorer
    Nov 04, 2013
    As far as the patch goes, I'm afraid you won't know where the supports are until you start hacking into it. A stud finder may help but can't say for sure. Be aware the area to patch may have wiring so dismantle carefully.

    I like the look the Webseal variant of Eternabond gave given that I did recoat the entire roof. I think the vinyl backed product would be easier where the roof is sound but the edge seams are the problem area.
  • theotherbart's avatar
    theotherbart
    Explorer
    Nov 04, 2013
    Great suggestions so far, thanks. Calamus, how did you "patch" your roof? Did you actually fix the water damaged wood under the rubber roof membrane or just patch over the rubber?

    Scott, what an epic project that was! Obviously you've been deep into the structure, if I wanted to cut out maybe a 2'x2' section of roof and replace the wood under the rubber how would I go about that? Going in I'd have no idea where the underlying structure is, or any idea how to fasten in the wood patch. And it isn't something I'd want to figure out as I went either, I'd rather have a solid plan before I started cutting stuff.

    No one has weighed in on which Eternabond product I should be using. It seems like WebSeal is the right stuff if I'm going to be coating over with something like Liquid Roof or the Dicor EPDM coating, is that correct?
  • Chopperbob's avatar
    Chopperbob
    Explorer
    Nov 04, 2013
    First clean it real good. Then apply Bus Kote.
    I've done three so far. Google Bus Note.
  • ScottnSherrie's avatar
    ScottnSherrie
    Explorer
    Nov 04, 2013
    I did a total roof rebuild in 2003 on my 1988. See the link in my signature.

    A two part EPDM product like the prior link or Liquid Roof is easy to work with. Eternabond is not cheap but excellent for seams and edges.
  • Ka_Ron's avatar
    Ka_Ron
    Explorer
    Nov 03, 2013
    There is a two step system for rubber roofs

    Here is a link to the manufacturer's website.

    It is almost like a paint for rubber roofs.

    Rubber Roof System
  • calamus's avatar
    calamus
    Explorer
    Nov 03, 2013
    Several years ago on our first camper we had much of the same problem the roof leaked by the vent in the back and ran down the wall behind the shower wall. ruined the shower wall. To repair I was able to pull the wall down and glued boards on where it was rotted put FRP on the shower walls and patched the roof. only did what was needed to make it work. So ya I have that camper along time.and the camper is still rolling down the road today still going since 1981. SO I say just fix it and use it if it was not 14 years old already I would say fix it right. just enjoy it! they have gallon buckets of elasto something its white and is awesome stuff will stick to firestone roofing and everything else. We used it on our layton with a tin roof on all the seams works wonders tape off where you dont want it though

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