Long Bubble in rubber roof

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Gulfgramma

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I have found a bubble in rubber roof on rv-Big/Major concern?? How can I repair before gets too bad. It's coming from under the AC. I am wanting to replace that anyway, so what do I need to look for on the roof to repair. Thanks again..
 
A picture would be helpful, but with small bubbles it is usually best to do nothing, larger may need attention. If you are going to remove the air conditioner anyway you will probably have access to the end of that bubble once it has been removed and could then insert glue into the area to stick it down again. Be sure to use a glue that is compatible with whatever the roof is made of.
 
Bubbles under membrane roofs are usually caused by moisture under the membrane which turns to vapor and expands, causing the bubble. A large area of loose membrane is susceptible to wind damage (such as going down the road at 65 mph) which could cause the entire roof membrane to delaminate from the substrate. When you remove the A/C, you could slice open the membrane, peel it back and re-adhere with an adhesive appropriate to the type of membrane. The slice can then be repaired with a self-adhering strip such as Eternabond. Of course if the substrate is wet and rotted, that will need to be replaced first.
 
Ray-IN said:
The adhesive used under a membrane roof is water soluble, as COCJ alluded to in his reply.
Find the source of water intrusion.
Click to expand...
Sometimes it's just shoddy workmanship at the RV factory when the membrane was glued down. The standards are low; EPDM makers (Dicor or Alpha Systems) don't even consider it an installation defect if there are "bubbles" with no adhesive. I doubt if they had giant ones in mind, but they don't give any specs on that (or at least not public ones).
 
Gary you are right. I just found this old 2008 thread: EPDM ROOF has bubbles ,is it done for...??

The Dicor FAQ page has this to say about roof bubbles: "

Will the air bubble effect the performance of my roof?​


No. The air bubbles will not blow up and pop. They will come and go with the weather conditions, humidity, etc. Please do not puncture the air bubbles. Air bubbles mean there is room for expansion and contraction, lessening the chance of stress cracks later."
 
Last edited:
Dicor also says...

My roof has air bubbles. Is this normal?​


Typically, if air bubbles occur they occur during or very soon after the roof has been applied. A couple of reasons for the air bubbles would be that they were not broomed out during application, and we ask the installer not to stretch the material during installation to allow for expansion and contraction of the membrane. Air bubbles will occur with weather conditions and humidity. Air bubbles can also occur at the seams of the roof decking due to flexing and twisting that occurs during transit. Sometimes they occur if there is a significant difference in the temperature between the inside and outside of the unit.
Click to expand...

However, I think Dicor is reluctant to say anything negative about the installation, since the RV manufacturers are their primary customers. As long as the bubbles don't cause an increase in Dicor's warranty claims, they aren't going to complain in public. And it won't - the EPDM or TPO membrane will hold up adequately. The concern is whether it completely detaches from the roof at a seam, and that's an issue for the RV builder rather than Dicor.

The other question here is the size of the "bubble". Is 3-6 ft of loose roof membrane a bubble or a detached roof?
 
I agree with Gary. A large bubble is a concern as wind can continue to further delaminate the membrane. It is possible that air infiltration from the A/C unit can put pressure under the membrane but not likely. I stand by my original recommendation to slice open the membrane and re-adhere with a solvent based adhesive and patch with a product like Eternabond
 
Gary RV_Wizard said:
Dicor also says...



However, I think Dicor is reluctant to say anything negative about the installation, since the RV manufacturers are their primary customers. As long as the bubbles don't cause an increase in Dicor's warranty claims, they aren't going to complain in public. And it won't - the EPDM or TPO membrane will hold up adequately. The concern is whether it completely detaches from the roof at a seam, and that's an issue for the RV builder rather than Dicor.

The other question here is the size of the "bubble". Is 3-6 ft of loose roof membrane a bubble or a detached roof?
Click to expand...
I have an 02 Fleetwood and line shape like a small tube under the rubber roof. It just showed up after I washed it. I'm thinking there may be a spot under the air conditioner that was loose and water got in there when I washed it. Since I may replace AC; I will fix it from there..Sounds like your suggestions to do that will be best..
 
COCJ said:
I agree with Gary. A large bubble is a concern as wind can continue to further delaminate the membrane. It is possible that air infiltration from the A/C unit can put pressure under the membrane but not likely. I stand by my original recommendation to slice open the membrane and re-adhere with a solvent based adhesive and patch with a product like Eternabond
Click to expand...
Small sliver of an air pocket, so if it is coming from under the AC since I washed it-I may start checking there and inject eternabond..Thanks
 
Ray-IN said:
Gary you are right. I just found this old 2008 thread: EPDM ROOF has bubbles ,is it done for...??

The Dicor FAQ page has this to say about roof bubbles: "

Will the air bubble effect the performance of my roof?​


No. The air bubbles will not blow up and pop. They will come and go with the weather conditions, humidity, etc. Please do not puncture the air bubbles. Air bubbles mean there is room for expansion and contraction, lessening the chance of stress cracks later."
Click to expand...
OK Dicor response may or may not apply here, as the little air line showed up after I washed it: running hose and broom, no pressure washer. The line starts under the ac and is about foot long. Old roof 02 Fleetwood, so maybe just a part unsealed and water got in..I need to check it again to see if it's larger or same, or gone..I may be replacing the AC, so good time to check then. Thanks
 
Kirk said:
A picture would be helpful, but with small bubbles it is usually best to do nothing, larger may need attention. If you are going to remove the air conditioner anyway you will probably have access to the end of that bubble once it has been removed and could then insert glue into the area to stick it down again. Be sure to use a glue that is compatible with whatever the roof is made of.
Click to expand...
It's been raining, so not climbing on the roof here lately, but it is a small sliver of an air line about a foot long. It is coming from under the AC unit and just showed up after I washed the roof: running water from a hoes and broom, no pressure washer. 02 Fleetwood, so from all the info received I think it may just be a separation of the EPD roof under AC, I think that's where I will begin search..Thanks.
 
Gary RV_Wizard said:
Dicor also says...



However, I think Dicor is reluctant to say anything negative about the installation, since the RV manufacturers are their primary customers. As long as the bubbles don't cause an increase in Dicor's warranty claims, they aren't going to complain in public. And it won't - the EPDM or TPO membrane will hold up adequately. The concern is whether it completely detaches from the roof at a seam, and that's an issue for the RV builder rather than Dicor.

The other question here is the size of the "bubble". Is 3-6 ft of loose roof membrane a bubble or a detached roof?
Click to expand...
It's more a finger line pop up comes from under Ac after I washed the roof. Hose n running water no pressure washer..Since I have an older 02 Fleetwood, I am getting the picture from all of your feedback could just be a separation in the EPDM after washing it..Thanks for info.
 
If it is a small finger line I wouldn't worry about it. In the commercial roofing business, the general rule of thumb was if the loose area was larger than one square foot, it needed to be cut and patched.
 
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