RV leaks/roofing fix

I have always had an RV. Its in my blood. My current RV is a permanent trailer at a campground here in Canada. It has been sitting here since 2004. It is a 92 Holiday Rambler Alumalite. I chose it primarily because the structure is entirely aluminum; skin, studs, roof, everything. Even if it developed a leak and all the wood rotted, it would still be a sound structure worthy of repair.

It has this nasty habit of developing a tiny leak somewhere each year. Normally its not an issue, I just go up and patch it with liquid latex.

But I'm wondering if there is something I can spray on... kinda like undercoating or bedliner but not black. Almost like spray-on rubber that I can apply to make a flexible, one-piece, spray-on roof. Google-fu turns up very little.

Maybe the screen door on the bottom of a rowboat spray?

Seems like the job for an adhered synthetic rubber membrane rather than a spray on product.

Plasti Dip seems to fix everything now days.

http://www.walmart.com/ip/Kool-Seal-White-Elastomeric-Roof-Coating/17210942

dculberson wrote: Seems like the job for an adhered synthetic rubber membrane rather than a spray on product.

This, stuff works wonders, I've seen it used as floor covering in work trucks and it still holds up.

dculberson wrote: Seems like the job for an adhered synthetic rubber membrane rather than a spray on product.

Not so much because you have to cut the membrane for all the vents, antennas, and domes. You're intentionally making seams where there are already leaks. It will last for a few years but the heat and cold cause pulling of the adhesive and the UV kills the sealant.

Membrane roofing works very well on the places where the existing roof can't leak. It also has engineered seams and failure points right at all the places where the existing roof can leak.

(can you tell I've tried a membrane roof on an RV before?)

Fueled by Caffeine wrote: http://www.walmart.com/ip/Kool-Seal-White-Elastomeric-Roof-Coating/17210942

This is what is on it now. It seals for a couple months and then cracks with UV.

curtis73 wrote:

Fueled by Caffeine wrote: http://www.walmart.com/ip/Kool-Seal-White-Elastomeric-Roof-Coating/17210942

This is what is on it now. It seals for a couple months and then cracks with UV.

rats. I tried the easy idea first.

How about something like Hydrostop or Sealoflex. If you could lap the joints with the cloth and paint on coating it might slow down the cracking.

Working around pools in Florida it becomes really obvious that white materials don't handle sunlight well. Anything white gets brittle and dusty while the same item in any other color keeps looking New. It might apply to that stuff as well. Any other color options?

Toyman01 wrote: How about something like Hydrostop or Sealoflex. If you could lap the joints with the cloth and paint on coating it might slow down the cracking.

I've heard of that before. I'll have to research it. Thanks.

I've never met a sprayon that works. I use a clear painton called "through the roof" that does the job.

MrJoshua wrote: Working around pools in Florida it becomes really obvious that white materials don't handle sunlight well. Anything white gets brittle and dusty while the same item in any other color keeps looking New. It might apply to that stuff as well. Any other color options?

Car is in Canada. There is no sunlight. That is why the roof leaks. Obvious solution is to pull the RV farther South.

Check out www.grizzlygrip.com It's a DIY urethane bedliner type material. I applied the white, fine grain type to my cracked to hell plastic popup camper roof a few years back. (Curse you Coleman!) No chalking or dusting and it's re-berkeleying-diculously tough. Last winter while sitting outside in the BRUTAL cold, it developed some small cracks, but I'm 99.9% sure this is from the plastic substrate shrinking and cracking further since I didn't do a single damn thing to fix cracks before applying it. I'm pretty sure you want the aliphatic version for constant UV exposure, and I think I saw instructions for direct metal application on their site. AND it comes in a bunch of colors.

The seem like a small business and good folks to deal with.

curtis73 wrote:

dculberson wrote: Seems like the job for an adhered synthetic rubber membrane rather than a spray on product.

Not so much because you have to cut the membrane for all the vents, antennas, and domes. You're intentionally making seams where there are already leaks. It will last for a few years but the heat and cold cause pulling of the adhesive and the UV kills the sealant. Membrane roofing works very well on the places where the existing roof can't leak. It also has engineered seams and failure points right at all the places where the existing roof can leak. (can you tell I've tried a membrane roof on an RV before?)

That's how roofing works. Yes you have to flash and seal around protrusions correctly. But any other product is going to leak faster. I think you're looking for something that doesn't exist - a liquid product that dries and becomes water tight for more than a year.

A membrane with proper flashing and adhesive will last for a long time, even on an RV. That's what good RVs have as roofs. Climb up on top of a $200k rv and you do not see a poured on roof.

dculberson wrote:

curtis73 wrote:

dculberson wrote: Seems like the job for an adhered synthetic rubber membrane rather than a spray on product.

Not so much because you have to cut the membrane for all the vents, antennas, and domes. You're intentionally making seams where there are already leaks. It will last for a few years but the heat and cold cause pulling of the adhesive and the UV kills the sealant. Membrane roofing works very well on the places where the existing roof can't leak. It also has engineered seams and failure points right at all the places where the existing roof can leak. (can you tell I've tried a membrane roof on an RV before?)

That's how roofing works. Yes you have to flash and seal around protrusions correctly. But any other product is going to leak faster. I think you're looking for something that doesn't exist - a liquid product that dries and becomes water tight for more than a year. A membrane with proper flashing and adhesive will last for a long time, even on an RV. That's what good RVs have as roofs. Climb up on top of a $200k rv and you do not see a poured on roof.

I'll just have to take a picture for you... there are large expanses of aluminum roof that have no holes and therefore can't leak. Where it leaks is the flashing around the protrusions. A membrane roof would cover all the wide expanses (which I don't need) and then use adhesive around the flashings. I already have used a rather diverse amount of flashing adhesives that don't work. I want to apply something that does work. Big expensive pieces of adhered rubber with the same adhesives in the same leak-prone areas are not what I want.

I've owned four or five RVs with rubber membrane roofs. I also had an aluminum roof motorhome covered with a rubber membrane. Its expensive, needs constant maintenance, and leaks anyway.

ultraclyde wrote: Check out www.grizzlygrip.com It's a DIY urethane bedliner type material. I applied the white, fine grain type to my cracked to hell plastic popup camper roof a few years back. (Curse you Coleman!) No chalking or dusting and it's re-berkeleying-diculously tough. Last winter while sitting outside in the BRUTAL cold, it developed some small cracks, but I'm 99.9% sure this is from the plastic substrate shrinking and cracking further since I didn't do a single damn thing to fix cracks before applying it. I'm pretty sure you want the aliphatic version for constant UV exposure, and I think I saw instructions for direct metal application on their site. AND it comes in a bunch of colors. The seem like a small business and good folks to deal with.

Thank you! I will be calling them as soon as I get back stateside.

You're welcome. Here's a link to a full write up I did for the pop up camper site: http://www.popupportal.com/index.php?topic=66289.0

Like I said, I did have some failures but I'm pretty sure it was from lack of crack prep on my part. If I had to do it again, I would have filled and coated the cracks with 3M Marine 5200 urethane adhesive and made sure to overlap it onto the edges around the crack. Let that cure for a week and then coat with the GG. The 5200 is demon powered stuff - super strong and has 1300% elongation to break when cured. I think that would have secured the base layer and made the GG a permanent solution. In fact, I will probably try to patch what I have with the 5200 now.

If I were you I'd coat all the seams with 5200 before coating the entire top with GG.

curtis73 wrote: I'll just have to take a picture for you... there are large expanses of aluminum roof that have no holes and therefore can't leak. Where it leaks is the flashing around the protrusions. A membrane roof would cover all the wide expanses (which I don't need) and then use adhesive around the flashings. I already have used a rather diverse amount of flashing adhesives that don't work. I want to apply something that does work. Big expensive pieces of adhered rubber with the same adhesives in the same leak-prone areas are not what I want. I've owned four or five RVs with rubber membrane roofs. I also had an aluminum roof motorhome covered with a rubber membrane. Its expensive, needs constant maintenance, and leaks anyway.

Okay, sorry, I understand a little better now. One issue is that the flashing shouldn't be just adhesive. You need some sort of mechanical barrier as well. If you have a joint between the aluminum and a protrusion that is flat you'll end up with leaks every year because the adhesive will fail. Especially with a metal roof where things are expanding and contracting constantly.

You need overlap, mechanical overlap. I'm not sure how to achieve it with an aluminum roof. But I'm sure it can be done..

pilotbraden wrote: Maybe the screen door on the bottom of a rowboat spray?

it comes in several colors now, and the one brand can even fix a boat that you shoot several times with a Civil War era cannon..

dculberson wrote: Okay, sorry, I understand a little better now. One issue is that the flashing shouldn't be just adhesive. You need some sort of mechanical barrier as well. If you have a joint between the aluminum and a protrusion that is flat you'll end up with leaks every year because the adhesive will fail. Especially with a metal roof where things are expanding and contracting constantly. You need overlap, mechanical overlap. I'm not sure how to achieve it with an aluminum roof. But I'm sure it can be done..

No worries. The aluminum sheeting on the roof is cut for the openings (domes, vents, etc) and flared up. It is carefully engineered for leak-proof operation for slightly longer than the warranty

I'll see if I can get a picture soon. I have sporadic internet on my laptop but my phone/camera doesn't like to connect up here in the wilderness.

dculberson wrote: You need overlap, mechanical overlap. I'm not sure how to achieve it with an aluminum roof. But I'm sure it can be done..

I completely agree, but RV roofs are flat, so mechanical overlap is very difficult. I found a photo. this isn't my roof, but its similar:

Notice how its one big flat piece. Then they cut through it and screw down a flange with sealant. There kinda isn't any mechanical overlap available. But, you can see how a membrane roof won't really help me. The wide expanses of sheet aluminum can't leak, and a membrane roof would simply overlap the seams and be bonded with an adhesive that will eventually fail. Mine currently leaks around one of those flanges (where the brown sealant is in the photo.)

The other problem I have with many of the elastomeric products is that they go on so thin. Cracking is inevitable. I thought something like a 3/16" thick spray-on bedliner type product would bond better at the edges and work kinda like a spray-on thing. Its not as forgiving of expansion and contraction, but it works in truck beds when its cold and hot, and an RV roof doesn't get that kind of punishment.

Although I could be on the wrong track (which is why I asked here :)

Google up "Dow 123". Basically it is Silicone tape. It's flexible and made to bridge seams. Bond to various things like PVC using the appropriate silicone.

Take the fixtures/flashings off, replace the putty (actually putty tape) underneath the edges, replace, enjoy. Anything else is temporary at best. Putty tape dries out after 22 years and fails to seal. Any RV store carries it.

Margie