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whatinZamzoo's avatar
whatinZamzoo
Explorer
Jun 23, 2022

What should I do if my EPDM roof turns black

Hi, I have a trailer with EPDM rubber roof. I was wondering if I can use eternabond or if I'd have to do something else. I have no idea if that's the EPDM itself or just mold which google seems to heavily imply that is most cases. Also I'm confused, because some people online say "recoating" but then some say well if you don't recoat you'd have to put a new EPDM roof. What exactly is the difference? It's just about 0.5~1ft of EPDM that's making my slideout roof get bubbles from the inside of the slideout right above the dining table which is an indication of water damage I believe. I will take care of the high roof side which is next to the A/C right after I fix the slideout issue. Any advice would be much appreciated. & yes I do suspect it's because of the A/C water dripping.


Here are some pictures
  • rhagfo wrote:
    Well I would never use bleach or other harsh detergent on the roof. We put Heng's rubber roof coating on our last year and doing well so far.
    If you want to try it they suggest using powdered Tide laundry detergent. I mixed up a strong bucked full with warm water and a medium stiff scrub brush, hands and knees job, scrubbed a about 3' square section at a time then rinsed well. Then when finished rinsed the whole roof again let it dry over night, then applied two thin coats.

    This is during scrubbing, line just above the vent.



    This is the product, got ours from Amazon.



    This is the finished roof.



    Oh wow that looks super amazing! Unfortunately I just saw your comments right now & already grabbed some stuff called super silicone seal by bergstromm industries. Bought a gallon for $200 I know pretty expensive but it covers 7sqr ft & I only need about that much. Just doing it for some breathing room for when I do actually replace the whole slide out epdm & later main roof. I will update this post every few months if I'm able to. Apparently it is a low preparation sealer. Again I love the work you did pretty amazing job!
  • That looks great Russ!!

    If that continues to hold up for several years, it was sure worth the work! Those hands and knees jobs are the best to get quality results.

    Jerry
  • rhagfo's avatar
    rhagfo
    Explorer III
    Well I would never use bleach or other harsh detergent on the roof. We put Heng's rubber roof coating on our last year and doing well so far.
    If you want to try it they suggest using powdered Tide laundry detergent. I mixed up a strong bucked full with warm water and a medium stiff scrub brush, hands and knees job, scrubbed a about 3' square section at a time then rinsed well. Then when finished rinsed the whole roof again let it dry over night, then applied two thin coats.

    This is during scrubbing, line just above the vent.



    This is the product, got ours from Amazon.



    This is the finished roof.

  • When EPDM roof material starts to turn black it means the top coating is failing and washing off.

    You can paint on all kinds of roof coverings that CLAIM to restore the EPDM but in reality very few will actually stick to the black membrane once the white coating is gone.

    Maybe RV Armor which uses a glue-like primer but expensive. Replacement is the only real, dependable/durable option. Unless you like peeling coatings that need replacing every couple of years.

    Went down that road, thinking it was just mold but the more I cleaned, the blacker the roof got. Then I learned.
  • Makes me wonder---everything around here turns black from the atmosphere. Side walk, roof, anything light colored and horizontal. I wash and re-coat the DP roof and pressure wash the sidewalks every couple of years. Probably air pollution drifting from the cities out here in the country--LOL.
  • Test a small spot with a dilute bleach/water mix (rinse well after testing). If it quickly turns white, it's likely mold. If not, the roof is nearing the end.

    Coatings are a stop gap measure that will buy you a year or so if the roof is near the end.
  • Use something like Clorox CleanUp and a soft brush and see if the black comes off. If so it is mold.

    If not, UV has destroyed your roof. I would not trusted ANY kind of coating to last more than a year. Remove and replace. I'll bet there is rot underneath!