Roof bubbles?

[William52]

Looked at an 99 National Trop-cal Top of roof was OK and just saw a place at front cap that needed a little caulk. Then later in diff. light I noticed bubbles along the edges or round down? Some were one to two inches in diameter rather large I thought. Is that delamlation or what?

 

[driftless shifter]

I have a similar condition on the roof of my 93 Bounder. I determined that it was the edge of the sidewall outer skin popping free after the transition curve from the wall to the roof. Decided that I didn't want to cut the membrane to refasten or glue. I chose to simply run 6" wide Eternabond Webseal front to back covering the long seam at top of the wall and over the pop ups with a good overlap. Then I coated the the entire roof with Liquid Rubber. I also sealed the end cap seams with the Webseal. Webseal is different than the Eternabond tape which has a hard plastic outer skin for UV protection. Webseal is the same gooey adhesive but has a webbing embedded, the webbing makes it very pliable and moldable to underlying contours, It has no UV protection and needs an over coat of something. The pop ups are still there but it will be a loooong time before they come through the membrane and the rig is 23 years old already.This repair was done 2 years ago and has withstood south Texas wind and storms as well as highway speed with strong cross and headwinds. I consider it a cosmetic issue, and am confident that it will last as long as I want it too. Will I have to do something to it later? Maybe but I doubt it.

http://www.eternabond.com/WebSeal-p/cr-wb.htm

Bill

 

[William52]

Thanks Shifter, I thought it was not a deal breaker but just did not look right and figured a repair was needed. The jacks and Genset in-op and a water leak up front at the corner windows made us walk away.

 

[Gary RV_Wizard]

Not delamination, at least not in the usual context. The roof membrane is glued to the substrate, and not always 100% of the surface is glued. In my opinion that is sloppy workmanship, but the roof membrane manufacturers all say is it not necessary for their product to be 100% adhered. This is especially true of fiberglass and metal roofs, but it has become common with EPDM and TPO as well.

The problem, if it is one, is that the venturii effect of air rushing over the roof sucks the membrane up, continuously pulling it away from the substrate as you drive. If enough loosens up, is looks funny - others see an obvious bubble as you drive along. But does it leak? No.

It's also easy enough  to fix if you want. Make a tiny slit, or use a syringe, and inject some adhesive to stick it back down. Then heal the tiny opening with lap sealant (roof caulk) or Eternabond tape.