Forum Discussion

billie_b's avatar
billie_b
Explorer
Oct 23, 2019

Preventing Butyl Tape from oozing out

Can butyl tape on the outside seams be sealed with a larger caulk joint so it does not ooze out? Seems like most people are used to trimming it off when it gets ugly. My Lance camper has a cap seal over the butyl that only butts up to trim and hatch moldings so it oozes out over time.

It won't look as nice but I was thinking of capping it with a wider caulk joint using a Dicor Lap or Proflex RV Flexible sealant but wondered if the oozing butyl will exert TOO much pressure and lift off a larger cap seal?
  • I wouldn't worry about it. Al the joints move over time, oozing out is normal. There is still enough to seal the joint.
  • I use pro-flex for covering over the Butyl tape. Have been able to stop all the oozing except the door threshold plate, TCing since 2002!
  • That's how my Wildcat TT was built. THey put a small bead of caulk on the outside of the edge of the windows. It worked fairly well but still oozed out in some places over the years.

    Our AF wasn't done that way. The putty is oozing out and I just cut the excess off with a plastic razor blade.
  • billie b wrote:
    Can butyl tape on the outside seams be sealed with a larger caulk joint so it does not ooze out?


    My experience says "no"

    Here's my experience: I bought a used travel trailer last year. it was a 2015 model. It had oozed a lot in the 3 years it sat outside at the previous owner's house.

    I cleaned up the ooze, then caulked over it last year. This year it oozed through the new caulk I applied.

    EPIC FAIL.
  • My butyl tape has oozed out over the last 3 years, but has slowed down the rate. However, in some spots it had became dry and flaky. Some chunks had fallen out, creating gaps, allowing some water to get between the side fiberglass and trim on the cabover (discovered some rusty screws at lowest point underneath that pullout trim that covers the screws).

    This spring I trimmed all oozed butyl flush around entire camper and caulked over with non-sag dicor. So far so good, even with our 100+ degree summer. We'll see how it holds up. Hopefully a long time as working with dicor was a huge pain.

    I'd say as long as all butyl still looks solid and is flexible without gaps, cracks, and totally fills the seams, just keep trimming. If it looks like it might no longer be doing its job in areas, scrape some out so you can run a nice bead of caulk.
  • Thank you all for your advice and I’m sorry for my late reply. My project has turned into a major project and I’m trying to finish before the rain comes-- more details to follow later.
  • Caulking isn't going to stop the oozing only time, warm temps and tightening any fasteners you can will it stop. My unit is 3 years old, most oozing has happened so it was time to redo all the exterior caulking after removing old material. I used the pro flex which was hard to work but I don't think it will attract the dirt like the dicor I used on roof edge earlier this year.