Delamination on 1986 Bigfoot

[Donna D.]

Good to hear you may have found a solution Since you're saying it's getting worse over time, do you know why??

[Lizbeth]

Tim, thanks for the pictures! That looks like what we have planned for our side walls.

The we get to tackle the sagging ceiling!

[Tim D.]

Donna, perhaps the problem was getting worse because of flex going down the road, but I'm not sure. We have driven a fair bit of washboard/potholed unpaved road. I'm just glad I no longer look to the great outdoors from the back edge of the galley.

The other day a 1979 "prototype" 17' Bigfoot parked next to us at Fred Meyer. Much of the port side seemed wavy and squishy. I didn't get a chance to speak to the owners much as they were in a hurry, so I do not know anything more about it.

[Daryl R]

This is my first post; let's hope I don't mess it up too badly.

I bought a 17' Bigfoot yesterday, the owners who were not the original owners, said it was a 1978, but when I went to register it the SGI had it in their computers as a 1970. I would really like to know the actual age the serial is 555** (last 2 numbers replaced with **).

Anyway my trailer has delaminations the roof sags with water damage, otherwise not in bad shape. This is what I suspect. The fiberglass shell is very thin with very little strength on its own. The way they most likely built the trailer, thin fiber glass shell to that they glued rigid foam and wood blocking where required for future attachments like bulkheads and cabinetry, beds, etc. Then the main wall paneling was glued to the foam. There is a good chance that this could have been done while the fiber glass was still in the mold. This type of construction would give an extremely light weight rigid shell. The interior cabinetry would also strengthen the trailer, by providing further bracing.

I believe the point of failure in these trailers at least ones of my vintage is that the glue between the fiberglass to foam and foam to wood is breaking down, and a guess that they did not have a water proof adhesive at the time that would work with the rigid foam.

Anywhere I can see delaminating I can see water damage as well. Now this is just a hypothesis on my part. I'm wondering if anyone can confirm this. If this is the case, I will have a lot of work ahead of me.

[Tim D.]

Daryl,

In the case of our trailer, water damage and delamination went hand in hand. The separation of the [fiberglass/foam/wood frame in places/decor paneling] sandwich seemed to be a combination of glue not holding as well as screws not holding in punky wood. At holmesonbigfoot web site you can ask a former Bigfoot employee specifics about the construction. He does expect a donation for his information.

We received contradictory opinions about the severity of our problem from the shops we visited. One shop predicted catastrophic consequences should we fail to repair. The shop that actually made the repair thought we could probably get away without making any repair. Everyone else was somewhere in between.

[Daryl R]

Thanks Tim!

I got through a few other posts last night, and have been thinking about it all day. The trailer most likely could use the roof repair the front third at least. This would require the removal of the upper cabinets over the dinette back to the closet on the galley side. If I was to do the complete roof I would have to remove the complete interior, and where do you stop. There appears to be only a small area in the back third of the trailer, so not likely a problem. There is also more roof support. I checked today on materials and the local auto body supply store has everything I would need. They also have a glue fiberglass/foam/wood, or metal. The chap there thought that on small delaminations one could drill small holes in the fiberglass and inject a small amount of glue making sure that there were holes for any excess glue to escape. He thought that just hand pressed would insure a bond; it might be a good idea to test this theory first, maybe testing with a piece of thin plastic laminate (Formica) and a scrap of rigid foam would make a good approximation.

As for structural strength small sections might be okay but large areas such as the front third of my roof are worrisome, not only for traveling, but winter snow loads. Also if there is undo flex in an area it is no doubt going to cause further problems. I would like to think you did the correct thing repairing your damage, did you notice the area getting bigger over the time that you first noticed the problem till the time you repaired it?

[Lizbeth]

Daryl, as far as we can tell our roof is not delaminated and does not have visible water damage. I think ours sacked out due to not having enough support to begin with plus the addition of an AC. It will likely November before we have time to tackle the project.

[Daryl R]

Tim,

I should reread before I post, you did say it got worse before you fixed it. The other thing I noticed was that the plywood had delaminated as well. The delaminating of the ply would be next to impossible to repair injecting glue. I worked on boats in the 80’s and very few types of plywood of the interior paneling types had waterproof glue. I think Bruynzeel brand plywood was the only one we could get with a guarantee.

Lizbeth

I’m not sure what the weight of an AC unit is but it would be my guess that it should have some support. If there is any delaminating between the fiberglass-foam-wood then you would really need support or repair. Think of corrugated cardboard if you have paper on both sides of the corrugations you have something that is fairly strong, take the paper off one side and you can roll up the sheet up. Somewhere in another post it said that later models of the Bigfoot had 2” of foam insulation, if all else in the construction was the same it would make for a much more rigid construction.