Scamp bottom of trailer--should I undercoat?

[BillE]

I have a question that undoubtedly someone on here has investigated.

I have a brand new 2016 Scamp 13 ft. trailer and the flooring underneath is what appears to be bare oriented stand board (OSB. I do not know if Scamp purchases waterproofs OSB or treats it in anyway (my guess is no).

So my question is ...should I undercoat the OSB on the bottom of the camper with automotive truck bed liner...or use an outdoor water proofing such as Thompson....or leave it bare?

I am looking for your thoughts and recommendations.

[redbarron55]

The floors can and do rot out, but the damage is usually where there are leaks that allows water into the interior spaces and stay. The floor rarely (if ever) rots from the bottom up.
The topside is sprayed ( I think the bottom too) with polyester resin to "waterproof"
If water stands it will rot. for example, under the carpet etc.
I am sure others will add more information.
On my rebuild I fiberglassed with cloth and epoxy both sides and the edges of 3/4' plywood.
Keep an eye on leaking windows (keep the tracks and drains clean) loose rivets etc.
I don't know what to suggest as I am a newbie, just rebuilding with an eye to improving reliability.

[Island Claire]

Redbarron55, you are just the person to ask my question to. Did you fiberglass both sides before you put the new floor back in or did you do the bottom side, put in the wood and then fiberglass the top. Thanks.

[BillE]

Thanks guys, mine is a brand new trailer so my intent is not to dis-assemble everything. So glass and resin is out.


My concern about undercoating is it may hold moisture and not breath.

[ludleywadzlo]

I used automotive undercoating (black tarry stuff in a spray can) to undercoat my trailer - which also had OSB subflooring. It can't hurt.

[redbarron55]

I cut and fitted the 3/4" plywood first. I also took a router and rounded the edges over so that the fiberglass cloth would form to it. The floor in the front was the first I removed and the ridge left from the old fiberglass was the guide for fitting.
I bought 6 1/2 oz. cloth and epoxy resin on ebay and the cost was not too bad for the protection.
When it was time to reinstall I cut strips from the cloth and layed up the bonding to the shell. The hardest part was fitting the wall in front of the door to get the door opening square.
I also bonded in 1/2" plywood bulkheads that make up the new front bathroom area.
I did not fiberglass these bulkheads overall.
On later bulkheads I bonded them in with polyurethane sealant/glue.
All of the floors are fiberglassed and bonded with that same glue to the frame. I also added frame work to the edge of the shell for greater strength overall. The plywood was affixed with screws closer than originally along with the bonding.
While working on the rest of the trailer I had leaking windows and the water pooled up on the floor, but none penetrated the fiberglass into the wood.
I layed down 1/4" cork underlayment over the floor (attached with the 3M spray adhesive). Under the bed I used some carpet and the walkspace I used vinyl laminate "wood" planks with adhesive tabs.
All in all I am happy with the way it turned out.
Connie wanted a camper with out bugs and creepy crawlies. Toward this end I filled in all of the vents etc for refrigerators and heaters etc. Lots of fiberglass work.

[Backwater Bill]

My last trailer had an OSB floor sandwiched between the vinyl floor covering and a woven poly fabric. This trapped moisture and the flooring rotted in several places. After I replaced and repaired the rotten sections I removed the poly fabric from the bottom and applied deck stain. I also used Krown T40 on the trailer frame to prevent rusting. I notice it wicked into the adjacent wood and waterproofed it with no apparent side effects.

[EugeneFlorida]

Originally Posted by ludleywadzlo

I used automotive undercoating (black tarry stuff in a spray can) to undercoat my trailer - which also had OSB subflooring. It can't hurt.

Wood needs to breathe One time I used the undercoating on a fence post. It rotted out. The post with no undercoating was OK.

Unless Scamp says to do it, when I pick up my 2016 Scamp, I'll leave It..

Just me

[Darral T.]

BillE, my Scamp's underside OSB was coated in polyester resin (fiberglass) My Scamp is nearly 6 yo and still looks fine underneath. I keep a watchful eye one it. What bugs me the most is my bumper and other parts of the frame keeps rusting? I'm concerned about welding joints internally and those areas of the frame more than I am the floor.

[BillE]

Darral T

Use POR-15 to paint your frame. Great product

[Jon in AZ]

Agree. The wood is treated with resin on the bottom, so no need to worry there. Best thing you can do for your floor is to watch for topside leaks from windows, vents, and plumbing. When new, check for any assembly defects that allow water entry, but after that just keep an eye on things. I wash and wax mine twice a year. That's a good time to look for seepage around windows. Check the floor inside the benches and cabinets, too, as water can run down behind the insulation.

I also agree that the factory paint on the frame isn't that great. One of these days I'll redo with POR. With a new trailer, you shouldn't have to worry for several years at least.

Don't worry too much and just get out there and enjoy the trailer. The more you use it, the quicker you'll notice anything that needs attention. The badly deteriorated trailers have usually been left uncovered and unused for many years.

[Paul O.]

When I visited the Scamp factory, I was told the floor is resin coated on both sides, then it is bonded to the shell. Driving on wet roads should not be a problem, it dries up when you stop.

The frame paint is pretty useless, traveling on gravel roads wears it off fast. Traveling on salted roads will make the frame rust. I repainted the frame with Rustoleum and the inaccessible surfaces that I could not paint I undercoat with WD40, sprayed on twice a year.

[gordon2]

I also wondered (and previously asked) about the cutouts, esp the one for the shower and commode drains. It appears that the cuts are made after the wood is treated, so the cut edges are then unprotected. I think its a reasonable idea to try and seal the cut edges.

[redbarron55]

This is quite true and in my side bath 16" Scamp that was true. The OSB was well soaked, swollen and rotted.

[jennykatz]

This is why I took scamp off my buy list .We made floor boards for the cockpit of our boat out of marine plywood and coated them with resin and then put an outdoor carpet on them they lasted a few years and then rotted out ( Our previous boat had a rounded hull so we made floorboards to compensate . Off course boats get a lot harder use then trailers . If you have the osb boards make sure you coat the edges and any holes that were made are sealed with resin .Living in SW Florida we see lots of moisture and mold down here so plywood (OS does not last long .

[Roger H]

This has been s a regular discussion topic for years. The experience of other owners has been that plywood and OSB that is encapsulated will be fine...right up until the encapsulation integrity fails, and moisture gets in. Then you get swelling, and ultimately rotting... and the swollen and rotted encapsulated wood is much more difficult to repair than if it had just been left open.

Earlier posters are correct when they say that most of the floor rot in Scamps comes from windows and through-hulls where the integrity of the seal fails, or the track drain gets filled with muck and overflows inside for periods of time holding the moisture agains the wood (from the top.)

Scamp has been in business a long time. They know their stuff. There are hard-use 30 year old stock Scamps out there with no flooring issues... but they've been well- maintained.

Use the trailer, maintain it properly and don't worry about the floor. It will serve you well.

[Paul O.]

Absolutely, well said, Roger. The idea is that any kind of standing water will cause rot, and mildew. In case of those trailers with 100% glass shell, standing water will still cause mildew and, possibly, health issues. Maintenance is key.

[Darral T.]

We use some REALLY high $$ "epoxy" paint here at work on some boat products. It made the hitch, bumper, etc look brand new. But unfortunately (and some people told me this would happen) it's popping back through. That's why I'm so disappointed. I figured if it was sealed it wouldnt do that...WHICH tells me I'm afraid there's an undetermined amt of moisture inside.

One other thing I forgot to mention, I'm not sure what it is, but my 2010 Scamp I bought new has a white paint? sealer? in all the water compartments on my Scamp. I'm sure that's to help repel water as well. BUT, the one thing Scamp does that I would NOT do if I was building/sealing...is leave RAW edges on the OSB. I personally feel like the fiberglass resin (IF it's on BOTH sides) is good! I just wish they had taken it to the next level and FINAL coated where screws and all go into the wood and the raw edges. After 6 yrs though...as I said earlier... my wood still looks good.

I'm VERY vigilant on leaks and one should be with an RV. This will help head off problems with rot. And really if you think it about it...that's no different than a house!

[Roger H]

Originally Posted by Darral T.

We use some REALLY high $$ "epoxy" paint here at work on some boat products. It made the hitch, bumper, etc look brand new. But unfortunately (and some people told me this would happen) it's popping back through. That's why I'm so disappointed. I figured if it was sealed it wouldnt do that...WHICH tells me I'm afraid there's an undetermined amt of moisture inside.

One other thing I forgot to mention, I'm not sure what it is, but my 2010 Scamp I bought new has a white paint? sealer? in all the water compartments on my Scamp. I'm sure that's to help repel water as well. BUT, the one thing Scamp does that I would NOT do if I was building/sealing...is leave RAW edges on the OSB. I personally feel like the fiberglass resin (IF it's on BOTH sides) is good! I just wish they had taken it to the next level and FINAL coated where screws and all go into the wood and the raw edges. After 6 yrs though...as I said earlier... my wood still looks good.

I'm VERY vigilant on leaks and one should be with an RV. This will help head off problems with rot. And really if you think it about it...that's no different than a house!

You need to use a rust converter like POR-15 to reduce the iron oxide as a prep before you paint the metal parts if you want it not to continue to rust.

And they don't do a final coat on the edges or bottom of the floor because experience has shown them (and now you, after six years) that it just isn't necessary. With the proper maintenance on the coach part of the trailer (windows and through-hulls) in another twenty years, your floor will look just about the same as it does today.

This really is a non-issue folks. Floor rot comes from leaks in the trailer, not from underneath the floor.

[Darwin Maring]

You can not go wrong by undercoating. Should you not do it and something happen then you will kick yourself in the butt for not doing it.