Minor EPDM Repair

[trainsktg]

Well, I think this is a new one.

While prepping for an upcoming 8,600 mile trip with the family, I discovered an approximately 6"x6" raised bubbled area on my EPDM roof, right next to the low corner of the shower skylight, right above the showerhead inside the coach. It is spongy in both feel and appearance.

Assuming there was a sealant leak, I did a careful visual inspection of the area, including a search for small cracks in the skylight itself and pinholes in the roof. Nothing was found. In a epiphany, I went below and removed the inside assembly of the skylight, exposing both the framing members and the outside layer of skylight. Aha! Although there was originally a 'vapor barrier' installed (actually, just some mastic tape) it had dropped loose. Since I have used the RV for the last two years to live in while away from home due to work, I am assuming that the hot mist from my daily showers managed to migrate around the inside layer of the skylight and accumulated in the underside of the EPDM. Since the RV has been in use through the last two winters, I'm sure that delamination due to freezing temperatures has caused the bubble.

Now I'm stuck. I've got a moist spot under there that needs to be addressed. I need to cut out the affected portion of the roof, repair the damage and then reseal the hole. I am assuming once I have finished repairs (including the vapor barrier), I can either slap a piece of Eternabond over the hole and cover it with some Liquid Roof or use an EPDM repair kit and just fuse an EPDM patch over the hole. Is one method preferable over the other, or is there another better method?

Suggestions?

Many thanks .

Keith

[Ray,IN]

Do not cut the membrane!
Go to:DIY RV roof repair, Moisture in RV's
and scroll down about 1/2 way to "rubber roof", subtopic "bubbles". This is the normal and accepted procedure for addressing EPDM membrane bubbles.

[rsflight]

It sounds like the the skylight needs to be removed, the rubber cut back, and the damaged wood replaced. After all is repaired, reglue & seal the rubber. Use redundant seals where ever possible so that as time passes and the first seal fails the 2nd & 3rd seals still keep the water out. So seal the rubber, then apply Eternabond or roof patch or both, then seal the edges of the patches. This gives a 3x redundant seal. Painting and/or sealing the open framing wood may also be desired to reduce a future occurance. So that's the proper way.

You may find that by removing the skylight you have enough room to inject chalking, glue, or similar material in and around the swelled area. Then place several heavy objects on the roof to hold it all flat while chalking dries. Then reinstall the skylight. This approach replaces the failed glue in the plywood.