Rubber roof is BILLOWING!

[albow]

Cousin following me saw where my roof was floating and billowing high enough that he couldn't even see my ac and he was a good ways behind me. Wife saw it too as I turned off the highway toward the house. I got on the roof and could not find evidence where air would be coming in and getting under it. I did find a few spots that could use some caulking along the edge next to the gutters and what looks like a very small tear but it is probably less than 2 feet from the rear over to one side. It is so small I'm not even sure it's torn but it sure seemed like inspecting it fully would result in it being so.

We went through 2 hellacious rainstorms this week prior to returning home where noticed the billowing as soon as I hit the highway, but noticed no leakage into the trailer during these storms. The last one had hail but not enough to cause damage I would think. All I can figure is the epdm has come loose from the adhesive use when putting it down. I was on the roof immediately prior to leaving for this trip and I did think it looked a little wrinkled, but it's always had some wrinkle to it and I've heard there is some movement due to temperature. I have had bad luck with my roof in that it had to be replaced once from a tear and then the place installing a new ac tore the roof and put a new one on about 3 1/2 years ago. Unfortunately, they are out of business now to even ask about this.

Would this be something to take up with my insurance company? I'm already about to contact them anyway because of damage suffered from a blowout and a second tire separating at the same time on the way back that I am going to post about. PS, Safeco roadside assistance SUCKS! They did try however. The lady said she contacted 15 different places and I was either out of area or they wouldn't service an rv. Apparently getting it towed wasn't a problem but when it wont roll, what good is that?

Any ideas as to what is going on? My first plan is to go ahead and Eternabond all my caulk sites just for permanence instead of recaulking but that wouldn't stop the billowing.

[Charlie_D_]

It is obvious that there are different opinions and some scientific examples. It is also obvious that some have difficulties with others opinions and examples. 🙂

[fj12ryder]

Wrong forum.

[gkainz]

fj12ryder wrote:
You have to have air pressure under the roof for it to rise:

"The difference in pressure between the bottom and top of the wing results in more pressure at the bottom, thus pushing the wing upward into the sky. This is lift."

Notice the word "difference". With no difference in pressure there is no lift.

I think you're implying an increased air pressure under the roof causes it to billow up, which may be true at times. However I believe a reduced air pressure above the roof can lift the roof - "suck it up".

But to your point of "difference in pressure" ... yes.

Bernoulli was a pretty smart guy. 🙂

[fj12ryder]

You have to have air pressure under the roof for it to rise:

"The difference in pressure between the bottom and top of the wing results in more pressure at the bottom, thus pushing the wing upward into the sky. This is lift."

Notice the word "difference". With no difference in pressure there is no lift.

[laknox]

fj12ryder wrote:
But unless you're creating a vacuum under the membrane there has to be a hole to allow the pressure to try and equalize. He just hasn't found it yet.

You don't need air "pressurizing" underneath the membrane to cause it to lift. Try this experiment. Take a regular piece of printer paper and hold it between your thumb and index finger of each hand along a short side, letting the rest hang down. Now, simply blow across the top of the paper. You'll see it lift right up. Use a drinking straw to more closely direct the airflow and you'll see that you don't need =any= air flowing underneath to create lift, only the air flowing across the top. Now, if you're talking enough lift to =fly=, yes, you need airflow across both sides of the airfoil for maximum lift. I'm not saying that there's =not= air getting underneath the roof membrane; I =am= saying that it's not necessary to create the effect.

Lyle

[railrode1]

It's a simple pressure difference. Even if the rubber was properly glued down, with heat and a positive pressure inside the RV, your're blowing up a balloon at 60mph. My Montana has front and rear attic vents up top, plus I crack open my roof vents while traveling. Like if you pull the drain plug on a boat while under way, it sucks the water out. I don't see this as a roof problem but a air entry problem. Find a way for the air pressure to equalize.

[fj12ryder]

Charlie D. wrote:
It is true about a few posts stating such. Not a lot of examples but this subject is not one of the more prolific problems. Consider all the openings on a camper. Basement doors and such are not air tight and they are just one way for air to get inside the living area of campers. The heater is under the steps going to my bedroom. If I open the basement door I can see light the the opening between the steps. The joints between walls, ceilings, closets and such are not sealed.

I absolutely agree that there are a ton of openings in the trailer, but they obviously don't cause any issues or you would see nothing but billowing roofs on virtually every trailer going down the road. But you don't.

[Charlie_D_]

fj12ryder wrote:

Charlie D. wrote:

fj12ryder wrote:
Like I said: no hole means no air under the membrane, no air under the membrane means no billowing. Takes two to tango.

I have seen several posts on this and other forums describing what billmac above this post stated. RV's are not sealed very well and considering slides, openings around the hitch and other areas I am not surprised that this would happen.

If that were true, then there would be lots of examples, but I've actually only seen a very few. I think the roofs are sealed pretty well.

It is true about a few posts stating such. Not a lot of examples but this subject is not one of the more prolific problems. Consider all the openings on a camper. Basement doors and such are not air tight and they are just one way for air to get inside the living area of campers. The heater is under the steps going to my bedroom. If I open the basement door I can see light the the opening between the steps. The joints between walls, ceilings, closets and such are not sealed.

[DickOK]

When a semi passes me with chrome doors on the back I can check my roof. Have done this for years.

[gkainz]

I saw 3 or 4 flapping rag roof 5ers while returning home to Denver from Custer, SD last week. Seemed so odd that I climbed up and checked my roof when I got home. I don't think I've noticed this in the past.

[fj12ryder]

Charlie D. wrote:

fj12ryder wrote:
Like I said: no hole means no air under the membrane, no air under the membrane means no billowing. Takes two to tango.

I have seen several posts on this and other forums describing what billmac above this post stated. RV's are not sealed very well and considering slides, openings around the hitch and other areas I am not surprised that this would happen.

If that were true, then there would be lots of examples, but I've actually only seen a very few. I think the roofs are sealed pretty well.

[albow]

billmac wrote:
My rv tech seemed to be very knowledgeable on this billowing problem. He said the air is coming up from the hitch into the front end cap and seeping under the roof trim. He said it is very likely the roof end cap trim piece is missing some screws which also helps the air get under the epdm roof. Turned out he was right. Many screws were missing on the front trim but were hidden by the liquid roof sealant the factory uses.

The tech removed the front trim, a/c unit, and cut a small hole that he covered with a faux plumbing vent. After gluing the rubber roof back down, he added a second trim piece next to the original to ensure no air would come under the roof trim from the front fiberglass cap. The hole job took him about 4 hours.

This was all done about 12 years ago. No issues since then.

Certainly sounds plausible. Sounds like it only cost you 4 hours labor plus a little bit in parts. Am I right?

[Charlie_D_]

fj12ryder wrote:
Like I said: no hole means no air under the membrane, no air under the membrane means no billowing. Takes two to tango.

I have seen several posts on this and other forums describing what billmac above this post stated. RV's are not sealed very well and considering slides, openings around the hitch and other areas I am not surprised that this would happen.

[fj12ryder]

Like I said: no hole means no air under the membrane, no air under the membrane means no billowing. Takes two to tango.