[vineyridge]

The roof seams are sprung and so are the side seams.

What should I do to seal them? What sort of caulk or tape or tape and caulk would be appropriate?

[Evalee Hunter]

Hire a welder?

[vineyridge]

It's at a metal shop now. The welder/metal fabricator doesn't seem to think that extra welding is necessary. It's just that where the sheets of steel butt against each other, the manufacturer's caulk has dried out and it leaks. There is no rust, mind you, that he has found; that's why he thinks caulking would be sufficient.

I'm wondering about the butyl products, and whether a tape would go on the inside wall with caulk on the outside, or whether the tape would go on the outside with caulk on the inside.

[BEARCAT]

Bumping this up as I have a similar issue with my trailer.

[Tom King]

Does it have aluminum strips over the seams? I'm not quite getting the picture but with more information I can tell you how to fix it. How are the sheets fastened to the trailer frame? Trailer manufacturer?

[vineyridge]

Does it have aluminum strips over the seams? I'm not quite getting the picture but with more information I can tell you how to fix it. How are the sheets fastened to the trailer frame? Trailer manufacturer?

Old all steel Hart. I have no idea how the sheets are attached, but there are signs of old white putty strip caulk in between where the sheet metal sheets butt up against each other. I'm assuming that the sheet metal was welded to the frame. You can't see any signs of caulk through the paint on the inside.

No aluminum anywhere.

[knightrider]

I knew someone who actually got a new skin on top to cover the old one...I'm facing the same issue at some point but am hoping I don't have to do it for awhile....

[vineyridge]

What I'm going to do on the roof is paint it with elastomeric paint that is used on RVs and mobile homes. I've found some with ceramic granules that is excellent insulation, and since the paint itself is rubberized and white, it should flex and also help seal the seams. What I'm looking for for the roof is a paintable seal over the seams that will work with the elastomer.

There are lots of different solutions out there; I would like to know whether I should use the special elastomer inpregnated tape over the seams or just a good quality paintable caulk that will allow me to use the elastomeric paint. I can also get butyl tape and butyl caulk that is very expensive but is touted for trailers.

[Tom King]

Are the seams butted or overlappping and what is the fastening method? A picture would be a big help.

The stuff to use is 3M 5200 or one of the Sikaflexes. Butyl doesn't last, as you found out, and silicone looses it's bond. I'd have to see the actual application to decide exactly which product. Anything I've used these products on since back in the '80s is still leak free.

http://www.jamestowndistributors.com...ne=1&page=GRID

Probably Sikaflex 291 if it's going to be painted over.

We have an old rustbucket 1990 Ponderosa that we pull cows in, and in a pinch horses, that I redid the roof on something over 10 years ago. It has overlapping seams and aluminum strips over. We power wire brushed the seams, after taking the alluminum strips off, sealed with 5200, painted with some industrial roofing paint for metal roofs from Sherwin-Williams, and repopriveted the strips back on sealing rivets with 5200. The roof still looks fine and doesn't leak but I can't find the motivation to work on the rest of it since it's mainly used once a year to pull some cows to market.

I'm not sure I'd use the RV stuff on a metal trailer roof. I wouldn't want to have to redo it.

[vineyridge]

The seams are butted, not overlapping. The metal sheets are welded to the frame. On the roof, the sheets butt on top of the roof ribs.

I was poking around at the Jamestown site and found a product named Sikaflex 221. Would that be appropriate? It can be sanded and painted over, but is elastic polyurethane. I also found a Sikaflex 721 UV that is for metal.

The 3M5200 is well loved by everyone, but is it paintable?

[Tom King]

5200 is not paintable. Any of the Sikaflexes are good stuff. I didn't read all the specs but if you found one that sounds right I'd go with it in full confidence. If there is any space at all between the sheets, I'd dig out as much of the old gunk that you can get out and inject some of the Sikaflex down in there as well as spreading a bit over the top.

A twisted wire cup brush on a 15amp sidegrinder is the best low tech method I know of to get down to bare metal through rust and old paint. Takes strong arms.

[vineyridge]

I called the folks at Sika technical support, thanks to the good people at Jamestown. The product that they recommended is their Sikaflex 252, along with their cleaner and primer. The 252 is both an aggressive adhesive and a sealant that will fill fairly large cracks. It is also paintable.

[JumpWithPanache]

DH just redid the trailer we bought in the fall ('97 Sundowner - all steel). I'll log him in this evening and he'll let you know what he did.

[vineyridge]

Thanks, JumpswithPanache. Other folks experience with such repairs would be greatly appreciated.