A Bazillion Roof Bubbles

[RussOnTheRoad]

A couple months ago we noticed some bubbles forming under the EPDM roof material above the bedroom in our barely 3 year old 29-5T. It seems to have gotten worse. If you look at the photo you will see countless bubbles.

We are looking for the cause and potential solutions.

We expect some sort of gaseous build up as opposed to a water leak. We have no staining on the ceiling inside the RV. We have not noticed any softness in the roof when walking on it as you might find with wood rot. It's hard to imaging how a leak would wind up distributing water to so many "blisters". We note the wide distribution of the bubbles. We wonder if it might be the glue that was used to attach the roof, if it might be breaking down and gassing out.

Any ideas?

[RussOnTheRoad]

UPDATE:In exploring the potential causes of the bubbling the mfr. suggested "heat from the sun" as a possible explanation. We rejected that because bubbling such as that shown in our photo would be a widespread, very common problem in RV roofs should heat from the sun be able to cause it, and because an insurance adjuster said it wouldn't be caused by the sun.

The mfr. seems to have been right, however, about the heat part, anyway. When they mentioned heat we were reminded of a fire back in 2019 that had occurred in the storage yard where I keep the RV when not in use. While there was no visible damage to the RV other than soot and discoloration marks on the roof from some embers that had landed on it, the front and rear of the RV did get exposed to heat from the fire.

When the fire occurred we filed an insurance claim with NGIC (National General used by Good Sam) and they paid for cleaning of the soot left by the fire on the RV. A few days ago I emailed NGIC requesting a new roof, and without any fuss at all they agreed!

We had documented our request well with photos, and we told NGIC what the adjuster had said. He was the original adjuster on the claim when the fire occurred, but he had moved since then to another company. We knew where he was and reached out to him, and he was willing to speak with NGIC on our behalf. I don't know if they contacted him or not, but in any event NGIC is making good.

Thanks to all who took the time to read my query and of course those who replied.

[RussOnTheRoad]

dougrainer wrote:
If you have it at the rear area, then the test drive is not needed. Are you POSITIVE the bubbles have not been there since day 1? Doug

Absolutely positive. I have spent a great deal of time on the roof, especially when I was installing our solar system when the RV was newish. Had there been bubbles I would have noticed them. I've also been up there tilting the panels from time to time, and many, many other times when checking and sweeping the slide tops for debris before closing them to role to our next location, cleaning the roof and skylights, etc.

[dougrainer]

If you have it at the rear area, then the test drive is not needed. Are you POSITIVE the bubbles have not been there since day 1? Doug

[RussOnTheRoad]

dougrainer wrote:
I want you to take the 5th wheel and drive 60 mph and have a friend follow you by the side in his auto. Have him get ahead of you and be able to observe the front roof top cap and see if he sees the rubber billowing up in the front. IF this front area behind the front cap are the only bubbles, odds are air is getting under that front cap seam. When this happens the front seam appears to be tight with no gaps. But at 60 mph, the air does get under and cause this type problem. I did not realize until I read your post again that the bubbles appear only in the front few feet. I thought you had this all over the complete roof, which is why I stated cleaning products. Doug

Thanks again.

We can certainly try to arrange the test you suggest but it would be a pretty significant undertaking for us.

Our RV has been stationery since 12/6/20. The bubbling has increased significantly since I first photographed it in mid-January. I think it rather unlikely that wind blowing would have created additional bubbling. I would also find it surprising that wind would create a great many small, apparently individual, independent bubbles as opposed one or two large areas. That just doesn't strike me as likely. Would you disagree?

BTW, we have found a few bubbles at the rear of the RV. Those are near where the roof ladder attaches. The lap seal there, as everywhere else, showed no signs of cracking last time I looked. I am not convinced there is much likelihood of water getting in there and cannot see how wind would get in there under any circumstances.

[dougrainer]

I want you to take the 5th wheel and drive 60 mph and have a friend follow you by the side in his auto. Have him get ahead of you and be able to observe the front roof top cap and see if he sees the rubber billowing up in the front. IF this front area behind the front cap are the only bubbles, odds are air is getting under that front cap seam. When this happens the front seam appears to be tight with no gaps. But at 60 mph, the air does get under and cause this type problem. I did not realize until I read your post again that the bubbles appear only in the front few feet. I thought you had this all over the complete roof, which is why I stated cleaning products. Doug

[RussOnTheRoad]

ken56 wrote:
Only idea is to take it back to your dealer and make a claim on a bad installation. Unfortunately you have to have the dealer document it and have them work with the manufacturer. The only think I believe if could possible be is a bad original install at the factory.

Thanks for the suggestions. I may just visit the selling dealer. They have a location not too far away. That said, I have already sent the same photo you've seen to the mfr. and they have not suggested it could have been a manufacturing issue, as you might expect, and although I have they have not refuted that possibility.

[RussOnTheRoad]

dougrainer wrote:
The most common cause of this mass of bubbles is a Incorrect use of a roof cleaning product. The product had some petroleum distillates in it and that is a no-no for EPDM roofs. Bubbles will NOT let water penetrate. Another possible cause, but rare for all those bubbles, is a roof edge seam is not sealed and when in transit air is getting under the membrane. But this usually causes a few LARGE bubbles. Doug

Thanks. Interesting thoughts.

As the original owner of this RV I can say categorically that unless it happened before purchase this roof has never had any roof cleaning product or product with petroleum used on it except for a few small spots where it was cleaned with mineral spirits prior to applying some Eternabond tape over a small tear. None of those repairs were anywhere near the bubbling and the mineral spirits was used sparingly, quickly and washed off. There is no sign of any EPDM separation or other damage in those places.

The roof seems well attached around the edges and there is no evidence of any seam failure anywhere else for that matter.

May never know what caused this with 100% certainty.

[dougrainer]

The most common cause of this mass of bubbles is a Incorrect use of a roof cleaning product. The product had some petroleum distillates in it and that is a no-no for EPDM roofs. Bubbles will NOT let water penetrate. Another possible cause, but rare for all those bubbles, is a roof edge seam is not sealed and when in transit air is getting under the membrane. But this usually causes a few LARGE bubbles. Doug

[ken56]

Only idea is to take it back to your dealer and make a claim on a bad installation. Unfortunately you have to have the dealer document it and have them work with the manufacturer. The only think I believe if could possible be is a bad original install at the factory.