Help! Trailer roof repair/replace advice...

Hey race fam.

I went up on top of my trailer yesterday to replace the roof vent and saw I have a much larger problem.

I've accumulated a good amount of rust and some of it isn't just simply surface rust.

I like to completely understand what I'm getting into before I start, so I'm asking for some help/guidance to repair or replace this roof.

It's a 16x7 cargo trailer with typical metal sheet roof. I do not have any current leaks.

I'm assuming this is a fairly straightforward, but tedious, job (please correct me if I'm wrong).

I plan to replace the roof and coat it/reseal so this does not happen again. Other option is to patch the "bad" corner area. Opinions?

Remove what I'm assuming is Dicor Lap Sealant (or the like) around the perimeter of the roof, assess what the sheet panels are held to the frame with (rivets maybe?), clean areas and reattach with new roofing sheets, reseal...?

Is there any mats or anything under the metal sheeting? If this is undamaged, it's okay to reuse?

I've included some pictures for reference.

Thanks for the help/advice.

 

Hey Anne, the only viable option is a brand new trailer.

 

you can address the surface rust with a product like por15s metal prep. The sealant can be scraped and redone with a roof coating once the rest is prepped. Better to apply thin layers of coating and build it up.

 

You have...had??...a galvanized roof. The zing has been used up in several areas...and now the steel is rusting. You need to remove the red rust, Convert it to a stable form and coat the roof to keep the exposed steel from continuing to rust. Removing the roof and re-skinning is a big big job on trailer that size. You could also clean and stabilize the rust and put a new roof skin on top of that one but you add weight and its still not the best repair.

Heres what I would do.
Use wire wheel, sand paper, etc to remove most of the rust.
Use a phospate/phosphoric acid based cleaner and rust rust converter to covert the red Iron III into stable black Iron IV. This prevents the rust from continuing to eat the metal. You want a rust converter that has tannic acid. Thats key.
Coat the treated areas with a good paint/coating. Something lilke por 15, bedliner in a can, or several coats of primer and top coat.
If any areas have holes or are structurally unsound, use a panel bond or structural adhesive to glue on a patch panel that is bigger than the bad area. Then coat that path the same as the other areas.

 

Looks like the roof is galvanized sheet metal, but even with it being galvanized it will still eventually rust especially with years of standing water.

I'd take a good angle grinder with a sanding disc to the worst section and see how easy it is to get to good metal. If you can get the rust off you can then seal it with a proper coating like POR15.

If there ARE spots that are too far gone, you can patch with more sheet metal/rivets and just make sure to apply lap sealant to any new seams/rivets.

I wouldn't go the route of trying to replace the entire roof.........most of it is in good condition.

 

This. Do not try to replace the metal. And POR15 for the final coat

 

Thank you guys so much!!! This is all SUPER solid advice and exactly what I was looking for (minus Broome's brand new trailer idea)! Next question: is the corner of the trailer different/more difficult than the rest? If I were to "reinforce" or patch the bad areas with new metal, should I cut out/remove the old rusted metal or just lay new metal over and seal it it?

 

If you can treat the metal so it wont keep rusting i would just do overlays and leave the under metal alone. It gives you something to bond to. The more surface area the more strength and sealing you can have.

 

I would do like Chemguy mentioned above. Wire wheel and sand it clean to get rid of as much rust as possible. Chemically treat the rust then seal it all up to protect it and prevent more rust. Then patch panel over it with an automotive strength adhesive, you know like the kind they can use to "glue-weld" panels on a car. Then treat that the way you do the whole roof for long term protection.

I just did this on my trailer minus needing any patches. I posted it the garage thread here http://forums.13x.com/index.php?posts/5698503/

I wire wheeled off all of the old sealant and paint, resealed the seams with trailer seam sealer/caulk, put some of the 6" wide permanent seam tape (waterproof) over all of that, and went over everything with a couple coats of waterproof and heat reflective aluminized trailer paint. I'm happy with it and it should hold up for a looooooooong time.

 

One other suggestion is to store the trailer iso that the roof is NOT level. If the water runs off, it will slow the process that got you to this situation.

 

I always raise my front end so any water rolls off the back end. Where I store my trailer it's crazy how many people have their trailer sitting flat just holding water on top when it rains

 

Get s good respirator, they are probably going to be hard to find but you will want one.

 

I wouldn't take the chance on the rust not reaching the tow vehicle, I would replace the trailer and the truck...

 

I’d EPDM the thing. A commercial roofer could do it in a couple hours.

Remove the vent you have, they’ll lay a piece of rubber over the roof, fold 1/2 back, apply glue, pull it over, pull the other 1/2 over, apply glue, pull it over, flat-bar the perimeter (may be able to reuse most of the perimeter trim already there), trim off the excess, and it’s done. With the vent, simply screw it in place and flash it. It’s done. The trailer will never leak. I’ve done a few trailers and even a motorhome.

 

That sounds like an awesome solution.

 

This. I coated the top of my 26 foot travel trailer a few years back with EPDM. Super easy and very durable.

 

Both of y'all suck!

 

But then she'll have to get a new house since the new truck and new trailer would look out of place at an old house.


Edit: I used to build trailers (well semi trailers) and putting the roofs on was a pita. One we built the roof panel was stressed and pinched to the top rail lip and once that was done the temp roof braces were removed. Its amazing how flimsy a 53' semi trailer is without the roof on. Little cargo trailers roof supports are usually permanent, so it wont get out of square too bad. Still its a big pita job.

 

A good day of sanding... hit with Acetone then throw a gallon of Koolseal on it...

 

For those of us not familiar with EPDM ...

https://en.wikipedia.org/wiki/EPDM_rubber

[edit] Found this video; looks like a good resource for application on a trailer.