The gray stains are dirt and/or black algae down in the pores of the rubber. You can add bleach to the cleaning solution to help clean it out, but mostly it just takes elbow grease. The problem is that repeated scrubbings will eventually wear away the compound that makes it waterproof, so don't scrub to long or too hard in any one spot. I suggest multiple mop & rinse cycles with a sponge mop rather than actual scrubbing, but you can use a soft-to-moderate bristle brush if needed.
Follow the directions on the bleach bottle to get the right strength solution.
At a rally, the roof people advised doing nothing. An attendee said it bothered him as he could see the top of his RV from an upstairs window since it was parked next to house. The instructor advised moving the RV ;D ;D
Has anyone had experience with the rubber roof base and topcoats? One of this summer's projects will be to remove all the old caulking and recaulk everything, and thought it would be an ideal time to renew the roof. Any suggestions/comments would be appreciated.
Are you talking about the paint-on re-surfacing stuff or just a "roof treatment" that is essentially a wax? Dave Derway coated the roof of his Monaco Windsor last year because the rubber had worn away in places and exposed the cloth backing. Lots of leaks. He bought several gallons of a roof sealer claiming to be for EDPPM roofs and it seems to have worked for him. Only problem was that it dried quickly and was difficult to spread smoothly before it got tacky. He wasn't real happy with the resulting aesthetics but it sure doesn't leak anymore. Maybe Dave will see this and add his own comments.
Thanks for the reply. Yes, I was talking about the resurfacing stuff. The roof doesn't leak yet, but as long as I'm up there..... It would be helpful to know if he used a brush or roller, which material, and the temp/humidity when he did it.
Gary is correct. Over the last 6 years of scrubbing our rubber roof to keep the chalking down, I managed to uncover the black backing in a couple of spots and had leakage problems that couldn't be solved by cauliking. The local RV place wanted over $6K to put on a new roof, so I looked for alternatives.
Folks in our Good Sam Chapter had used this something called ProGaurd? http://www.proguardcoatings.com/liqrubber.html and said it had worked for them.
It is a two part EPDM Coating (Rubber and catalyst) that you mix together and put down with a brush and roller. When catalyzed, the rubber has a working life of about 4 hours, and for a 36' motorhome and just one person, this is just barely enough time. Because I was running out of time, I wasn't able to smooth it out as well as I would have liked to.
To summarize a long story, it works great, looks so-so(my fault entirely) and saved me over $5K. I used 5 gallons of the stuff.
If you would like more information on the application, just let me know and I'll provide more of the gory details.
Curious about the prep. I had to fix some tears on the outer wrapped edge last year. I used the metal corner molding, and the pooling caulk stuff that they use when building. Worked great, but looking longterm, if I were to try what you did, what needs to be done to the surface first?
Bill, the rubber roof on my motorhome wraps over the side and goes down about 4 to 6 inches to a horizontal seam where it meets with the fiberglass sides. The first thing I did was to tape full newspaper sheets to the seam as the liquid rubber does sag a bit on the sides. I scrubbed the top really well to remove all chalking and loose caulk. I checked to make sure all screws were tight and any holes or tears were repaired and the repairs smoothed over. This probably was overkill, but I was really tired of having a leaking roof. The hardest part was scrubbing around the air conditioners. I did temporarilyremove the refrigerator vent cover.
The catalyst was mixed with the liquid rubber and this was applied to the roof with a roller. A brush was used on the sides and in all those spots the roller wouldn't fit. Once finished, the original rubber roof will swell a bit and you will think that you've ruined it for good. After a couple of hours of drying, the swelling will start to disappear and after 24 hours, it is all gone.
This stuff is super sticky, and I ended up throwing away everyting that I used in applying it, includeing my shoes, pants, shirt, brushes, rollers, etc.etc.etc.? :
Good thing you didn't get any in your hair. ;D
Mine oly wraps about a half inch or so, the molding I installed covered it pretty much. I do need to figure a way to drain the pool on the top hoever. I wish my camper had the powed roof, a definite plus for the next one.
I checked the ProGuard Coatings site, and they have 2 products that are essentially the same according to them; Liquid Rubber, and Liquid Roof. The Liquid Roof is only sold thru RV dealers and cost upwards of $350 for 5 gallons, whereas Liquid Roof from the factory is $203.50 + shipping. That's a whopping difference! I'll order from the factory. ;D Also according to them, the curing process can be slowed down or even halted by keeping the mixture cool, so I plan on doing it on a moderately cool day, around 65, and keeping the mix in a container of cool water. That should make the application process easier with less 'hurry-up-and-get-it-done'. Spent several hours yesterday removing old caulk and re-caulking everything on top. My veneer knife did a wonderful job of removing the old stuff without damaging the rubber, and would recommend getting one to anyone doing the same thing. Final cleanup before laying down the new caulk was done with Xylene(Xylol) and some old rags.
It sounds like you've got a good handle on preparations!
I had to look at the extra gallon I had and the stuff I purchased was the Liquid Roof, and like you, I found the factory to offer it cheaper than any RV places.
When I started coating my roof in the morning (as soon as it dried from the morning dew), it was in the high 70's and climbed into the low 90's before I finished. That's why it set up so fast on my, I'm sure.
The folks that mentioned this product warned me to get a HEAVY DUTY 1/2" drill for mixing it and they weren't kidding. They burned up a regular 1/2" drill when they mixed theirs. I purchased one of the el-cheapo Heavy Duty 1/2" high torque drills from Harbor Freight (they had it on sale for $39) and a mixing paddle from Lowe's. This was mixing the 5 gallon bucket. I followed the manufacturer's directions on mixing and it was pretty straighforward.
The catalyst is purple and the rubber is white, so you can tell when you've got it all mixed up.
Be prepared to have sore arms after mixing it up. That drill and the consistancy of the product will give you a real good workout.
Thanks for the info and the warning. Maybe I'll take a page out of Tom Sawyer; kinda like "I'll bet none of you guys are strong enough to mix this whole bucket...", or maybe have a roof coating mixing party - I'll supply the beer and brats, you supply the brawn.
Another question or two: How close was the coverage estimate of 45sq. ft./gal? Would you recommend brush application around vents, a/c units, etc. before the main application with roller?
I like that idea of the cookout. Just make sure the work is done BEFORE they hit the beer! ;D
Coverage was very close. I calculated 6 gallons needed for my roof and used exactly 5 gallons. Since I didin't subtract all the A/C covers, bathroom skylight, etc out of my calculations, I believe their coverage was spot on.
That's a good question about brushing around the vents first. I'd contact the manufacturer and ask them. They were very helpful in answering the questions I had via email. I just started at the front seam of the coach and went backwards towards the ladder with my application.
Interesting suggestion, but I don't think it would be practical for a couple of reasons. Firstly, neither comes in white, which is what we would want to reflect heat and secondly, being a closed chain polymer, you would have a heck of a time getting caulk to seal properly around any openings. An asphalt-based caulk might work, but they're really messy and collect a lot of road dust, etc. Another consideration may be the additional weight of those materials and their relative inflexibility, which could lead to leaks and seperation of the underlying rubber membrane from the coach roof. Don't think I'd care to chance it.