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ElBoCaDiLlO5 Dec 2025 16:06It started about three years ago, when I had a lot of snow on the garage roof during winter, piled up quite high in front of the air conditioning unit. I got the bright idea to quickly clear the snow off the garage. I did that, and only much later realized that I probably caused a tear in the EPDM membrane, through which water then entered. I only noticed this quite late, and since the ceiling consists solely of OSB boards, I tried to dry everything out, did some brief research, and patched the roof with MEM Dicht-fix sealing compound that was recommended to me at the local hardware store for such repairs. This initially seemed to solve the problem. The OSB board was stable and showed no signs of fatigue.
After about two years, many temperature fluctuations and sun exposure took their toll, and the repair apparently was no longer watertight, as mold appeared on the inside and spread quickly. The sealing compound had become porous and started to crumble. I then removed a section of the already damp and weathered OSB board, replaced it with a new piece of OSB, and glued overlapping strips of bitumen tape over it. But now this is leaking again, and I am wondering how I can achieve a long-term watertight result.
My plan now is to try drying everything out again and then glue an EPDM membrane over it. The problem is that at the damaged area I must adhere directly to the OSB board, while at the edges I will be bonding EPDM to EPDM. This will certainly leave some water trapped at the damaged section, but I imagine that should not be a problem as long as everything is sealed properly. Especially at the transitions, it needs to be watertight; is simply gluing it on enough? Originally, the membrane extends over the edge and is protected by the parapet. How can I create a secure transition, and how much overlap with intact membrane is necessary?
Is there a better solution than gluing a piece of EPDM membrane over the damaged area?
Thanks for any sensible advice. This seemingly simple repair seems to be more difficult than expected ;-)
After about two years, many temperature fluctuations and sun exposure took their toll, and the repair apparently was no longer watertight, as mold appeared on the inside and spread quickly. The sealing compound had become porous and started to crumble. I then removed a section of the already damp and weathered OSB board, replaced it with a new piece of OSB, and glued overlapping strips of bitumen tape over it. But now this is leaking again, and I am wondering how I can achieve a long-term watertight result.
My plan now is to try drying everything out again and then glue an EPDM membrane over it. The problem is that at the damaged area I must adhere directly to the OSB board, while at the edges I will be bonding EPDM to EPDM. This will certainly leave some water trapped at the damaged section, but I imagine that should not be a problem as long as everything is sealed properly. Especially at the transitions, it needs to be watertight; is simply gluing it on enough? Originally, the membrane extends over the edge and is protected by the parapet. How can I create a secure transition, and how much overlap with intact membrane is necessary?
Is there a better solution than gluing a piece of EPDM membrane over the damaged area?
Thanks for any sensible advice. This seemingly simple repair seems to be more difficult than expected ;-)
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