Sub Floor or Not

[boomboomtulum]

I've noticed that everyone buids a subfloor. Would it be possable to build a floor right on the frame. Say a 1/2 baltic birch floor on the 2" box tube frame, than extend the exterior wall which are 3/4 birch ply to the bottom of the frame? This is where the walls will be attached. I plan on insulating only the roof on this tear.

Dave

[Sam I am]

Dave, I used a sheet of 5/8" ply for my floor, bolted right to the trailer frame. I think many others have built this way too. It's a simple way to go. Putting the walls down over the frame works, too, but be aware that the whole structure will be a couple inches wider than your frame, so you might have to turn 4'x8' plywood sheets sideways to get your roof sheeting wide enough. Covering the frame rails looks good, though!
Sam

[boomboomtulum]

I just checked out your photos, nice. Mine will be 54" wide anyway.
Dave

[mikeschn]

Most people glue and screw their wall to the subfloor that you are asking about.

I suppose you could attach the floor right to the chassis... and attach the walls to the chassis using self tapping metal screws.

The way I would approach it is to first attach the floor (the 1/2" plywood) to the chassis, allowing 1/2" overhang on each side. Then I would come back with a laminate trim bit in the router and route the plywood flush with the chassis.

Then you could attach the walls to the chassis with self tapping metal screws.

I would consider using a silicone caulk to seal up the joint between the chassis and the wall, and the chassis and the floor.

I would also use roofing tar on the underside of the floor before attaching it to the chassis.

And I would apply the silicone generously on the sidewall before attaching to the chassis.

And the last thing you might want to consider is to use CPES on the plywood, since it's in direct contact with metal.

Mike...

[Sam I am]

One more point: If you use a bolt together frame, you will have bolt heads sticking out from the frame rails, so the walls cannot be screwed fast to the rails unless you put some spacers on the rails to let the walls clear the bolt heads. You would have to leave enough room near each bolt to get an open end wrench on the head to hold it while you turn the nut in case one worked loose. I would put tar on the spacers and the inside of the bottom 4" or so of the walls to waterproof that area.
Sam

[madjack]

...the way we doit...single sheet of ply(no subfloor) bolted diectly to the frame with self taping screws(commonly used for attaching deck boards on utility trailers)...1x1 Al angle attached to side walls(also single sheets), 2"s from bottom edge...this allows the side to come down over the steel frame...Al angle is glued and screwed to sides...set angle on floor so that side is pulled up tight against the frame and attach angle to floor(glue and screw)...use a heavy bead of sealant of choice to seal floor/wall joint...use those same self-taping screws to attach wall to steel frame...voila, floor/wall/frame are all now one piece...install bulkheads, cabinets, ribs, ceiling, electrical, insulation, roof, outer finish and go camping...oh yeah, windows, doors and a hatch might be nice to have as well
madjack

[boomboomtulum]

Great Info. Thanks for the ideas.

[grant whipp]

Hey, Dave!

I'm just up the road, so-to-speak, in Redding ... c'mon up and I'll show you 'round my shop, maybe give you some ideas. Drop me an e-mail - [email protected] - or a call after 6:30 pm (number's on my site - www.LilBear.teardrops.net )

Good Luck with your build, and let me know if I can help! In the meantime ...

CHEERS!

Grant

[Alphacarina]

One more point: If you use a bolt together frame, you will have bolt heads sticking out from the frame rails, so the walls cannot be screwed fast to the rails unless you put some spacers on the rails to let the walls clear the bolt heads. You would have to leave enough room near each bolt to get an open end wrench on the head to hold it while you turn the nut in case one worked loose

I wouldn't space the floor up off the frame to clear the bolt heads - I would bore holes in the floor where the bolt heads are and sit the floor directly on the frame. When you're done, you can fill the holes with epoxy so the bolt head is encapsulated and the floor is smooth and level wherever the bolts are - That would allow you to tighten the nuts from underneaath, though with nylon locking nuts on them, they shouldn't come loose anyway

Don

[bobhenry]

The 2x4 rim was glued and screwed 8" o/c the osb sub siding was then screwed to the 2x4 and a 1x4 cleat was installed inside and screwed to the osb sides to help carry the wall and roof weight and to act as a bottom nailer for the inside skin.

[Sam I am]

Don, I meant the bolt heads on the SIDE of the frame rails. Mike was suggesting screwing the walls to the sides of the frame rails (I think). I drilled holes like you suggested for the bolt heads on the top of the rails on my tear. Works good.
Sam

[boomboomtulum]

I am building the frame anyway a welded 2x2 .120 tube frame so no bolts will be on the frame. Even the stabilizers will be welded to brackets.

Grant thanks for the invite, I will e-mail or call you and see if we can set something up. I would love to see your shop and get some ideas.

Dave