Heng's rubber roof coating is the most recommended roof coating in this forum, and has very good reviews online. So I decided to try it for my aging rubber roof (16 years) which was still intact but starting to show a lot of black underlayer.So on a warm dry day last May I did it. I did what I thought was a thorough cleaning: detergent, rinse, thorough wipe down with acetone. Applied 2 coats Heng's with brush. Let dry. Next morning looked great. The whiteness was actually shockingly bright.But looks are deceiving. By day 2 I saw evidence of lifting in several places. Not small bubbles, but large areas of a square foot or more just lifting like a rubber sheet. So the coating is strong and loves to stick to itself but it is just terrible at sticking to the roof! What could be wrong?Nothing I can do now except strip it all off and start over. I haven't done that yet as I wanted to see how long it lasted. Not long it turned out. Over the course of the 6 or so camping trips last year I witnessed pieces tear off one by one until at this point about half of it is gone!Stripping the rest should be easy, I think it will peel off in big chunks. The question is what to replace it with? Unless I did something seriously wrong with the prep then Heng's is out. ProGuard? Dicor? Don't laugh but I am thinking of covering the whole roof with Eternabond - they do make it in 24" sheets. I've never had problems with Eternabond sticking.

A 16 year old roof is done. The coating stuck to the surface it was applied to, the surface just pulled away from the substrate. Anything you put on it will do the same. Replace the roof membrane.

I dunno if I agree with the above. My roof was 14 years old with lots of black rubber showing. It's been almost 4 years and my Hengs roof is holding up well. OP, sorry to hear about your experience.

I redid the rubber roof of our (then) 10 yeR old DSDP with the product from Minnesota RV Roofing.13 years later, now with new owners and no problems at all.Highly recommended!Bob

Sorry I don’t see how you can completely and correctly apply Heng’s in a single short day. I took three days to apply ours. Weather was clear and dry and daily temperatures were 80 to 85 degrees.Day 1 Removed all our MaxAir vent covers and cleaned all vents.Swept roof very well.Mixed a strong solution of powered Tide detergent and warm water and scrubbed a 3’ X 3’ section with a medium stiff scrub brush, then rinsed with lots of water. Once entire roof was washed I rinsed again, and allowed to dry overnight.Day 2 Waited until about 10:00am to start edging around all vents, AC, and bath skylight. Used a short nap roller to apply, worked on well and a thin coat. Not sure if I needed to open second gallon to finish first coat on day one.Allowed first coat to dry overnight.Day 3Applied second coat edged the entire edge of roof again with brush, then rolled on second coat again. This was allowed to dry overnight.I think using the acetone was likely a mistake, as Heng’s is an water based product.Ours is doing very well, as I used just under 2 gallons, I am considering adding two more coats this summer.

garyemunson wrote:A 16 year old roof is done. The coating stuck to the surface it was applied to, the surface just pulled away from the substrate. Anything you put on it will do the same. Replace the roof membrane.I agree with Turn The Page, the roof is not in need of replacement. Our 5er is a 2005 with the original roof. I just believe the OP rushed the application, especially the time from cleaning to application.

Very Poor Results From Heng's Roof Coating | Good Sam Community

agesilaus
Explorer III
Feb 21, 2022
larry cad wrote:
rhagfo wrote:

I think using the acetone was likely a mistake, as Heng’s is an water based product.

21 years old rubber roof with Hengs and no lifting. I agree, why did you use acetone?

My thought too, I thought acetone was specifically NOT to be used on rubber roofs. What do the instructions on the can say?
I used Hengs on our 2006 roof, went on easily and has held up well. Roof prep is the key.

Proper Prep Prevents P* Poor Performance.
larry_cad
Explorer II
Feb 21, 2022
I just chatted with Kim at Heng's customer service, and this is what she wrote to me regarding roof preparation:

"Yes, it would be due to the acetone is why it is coming off. The only thing we recommend for cleaning is a powder detergent such as Tide, Spic and Span, or Ox clean."

Thank you,

Kim Grantham

Customer Service

Heng’s Industries

(574) 295-1200
solismaris
Explorer
Feb 22, 2022
Guess a redo is in my future. No acetone next time. But I rechecked the Eternabond site and they do say clean with acetone prior to applying their product so I was not concerned about damage to the roof. I figured the acetone after it dries would not affect the Hengs but it somehow did. Or maybe I was not thorough enough with the scrubbing. So no more acetone next time, wait for a Very dry weather period, use powdered detergent, good scrubbing, good rinse, dry a long time, then try Heng's again. Wish me luck!
agesilaus
Explorer III
Feb 22, 2022
they do say clean with acetone

I believe, and I'm no expert, that acetone use depends on the type of roof. Some are OK to use it on, others not.
rhagfo
Explorer III
Feb 22, 2022
solismaris wrote:
larry cad wrote:
rhagfo wrote:

I think using the acetone was likely a mistake, as Heng’s is an water based product.

21 years old rubber roof with Hengs and no lifting. I agree, why did you use acetone?

Ok, no acetone next time. That is what was recommended for Eternabond so I thought that would be right for final cleaning before applying Heng's. But people seem in agreement that I rushed the job or screwed up the prep. I'll study the Hengs instructions carefully and try to contact somebody at the company for advice. And I'll do a sample area first and give it a month to test it.

No I didn't do it all in one day. More like 3. But it was somewhat faster because I did not remove any roof structures like vents because they were already well protected with Eternabond so I only recoated up to the Eternabond or slightly beyond.

I have never been a fan of Eternabond for sealing vents or other roof penetrations. That is what Dicor self leveling caulk is for. I know Eternabond tape is super sticky, but putting tape over irregular surfaces just doesn’t make sense to me. I see it as great for an emergency fix to the flat rubber surface, but not over screw heads, and uneven surfaces.
Thermoguy
Explorer II
Feb 22, 2022
Good Luck getting it off. Mine was done before I bought it. It has been peeling off ever since. I'm not sure how it was prepared or done, but done by the dealer as a way to extend the longevity of the roof. The guy I bought it from showed me a couple places it was coming off so I would not be concerned there was a problem with the roof. When I had the RV inspected, post purchase, the guy told me that is what they did and to take the coating off over time. Every year when I clean the roof I get more off. Peels in large or small sections. Now it's mostly off. I have thought about applying something like this but a post like this makes me think twice. My repair shop says don't do it. I want the roof to look better, but it doesn't leak so I guess it still works. Putting a new roof on is just a huge expense and no guarantees how long it will last. Other coatings sound good but too expensive considering to be just a coating. Anyway, good luck getting it off good enough to recoat.
Veebyes
Explorer II
Feb 22, 2022
larry cad wrote:
rhagfo wrote:

I think using the acetone was likely a mistake, as Heng’s is an water based product.

21 years old rubber roof with Hengs and no lifting. I agree, why did you use acetone?

Using Acetone is my suspicion also. Acetone is one powerful solvent. I use it everytime doing fiberglass work but would never consider using it on a rubber roof.

I did my roof a couple years ago on my 2007 5er. It had 'roof pox', the black spots but it was in decent shape.

Cleaned it with a regular car wash soap. Gave it going over with 50% clorox & water in an effort to kill the roof pox. Let dry then rinsed it off.

Rolled on two coats of Hengs Tropicool & it has been looking good ever since.
C_Schomer
Explorer
Feb 23, 2022
I made a similar mistake with mineral spirits. I was trying to clean every last bit of old caulk off of a small area and the mineral spirits rippled up the rubber membrane. I waited about a week and the ripples flattened out and the membrane look normal. The local trailer repair shop near me told me not to use Hengs and a local commercial roofing supplier told me to use Henry’s. I’ve done two RVs with Henry’s and I pressure washed to remove anything that would possibly break loose and then I used a Scotch-Brite pad and TSP solution to clean the membrane. I used Henry 587 on a previous RV when I lived in the Phoenix area and it still looked awesome after five years of outside storage, when I sold it. I used Henry 787 on this fiver two and a half years ago and it still looks like new, too. If I ever do another one I will use the Henry 887 which is 100% silicon and it is recommended for RVs. I’ve had zero problems with the cheaper Henry products though. Craig
BurbMan
Explorer II
Feb 28, 2022
solismaris wrote:
I did what I thought was a thorough cleaning: detergent, rinse, thorough wipe down with acetone.

This is the problem, right here.

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