Subfloor setups

[brundige]

So we have an elastomeric roof coat on our floor now and want to run out idea past some more people before committing. We are planning on taking 1/2" foam and gluing it to 4x8 1/4" plywood. We want to lay it down plywood side up with 1/4" gaps where the board butts the bus and 1/8" gaps between plywood. My only concern is that without having the plywood scrwed down to anything to may buckle irregularly. Any thoughts ?

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[Robin97396]

That's true, there can be some curl in the plywood if it's not held down by something. Most people have cabinets or other items that effectively hold down the floor and prevent warping.

That's generally called a floating floor and is pretty common in buses. I put screws in the corners and sides of the floor I did to make sure it wouldn't move or warp.

[brundige]

Cool, I called the paint company that makes the elastomeric roof coating that we were planning on applying on the floor and they said absolutely not because of gasses that it releases. Does anyone know if there is a safe Interior paint that has the same properties as the elastomeric roof coating?

What did you screw into ? The metal floor? Is there a special kind of screw ?

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[Robin97396]

People have been using a number of methods to treat the rust on the steel floor. Ospho to kill the rust, then other treatments including Rustoleum. I've never heard anyone mention the solvents on these normal rust treatments. I can understand how an exterior sealant could have harmful solvents in it in comparison to other treatments, but I don't know much about that.

Yes, I just drilled pilot holes and put a wood to metal screw in each corner of the plywood sheets as cut to make the edges match. Don't make them to tight if you're including rigid insulation in your floor.

[bstewrat3]

1/4" plywood isn't going to give you much support to keep from denting the insulation underneath. I used 1" insulation and 3/4" tongue and groove Drymax OSB. I offset the seams of the insulation and the plywood to keep the seams from having a common weak area. All of mine is glued down.

[brundige]

Originally Posted by bstewrat3

1/4" plywood isn't going to give you much support to keep from denting the insulation underneath. I used 1" insulation and 3/4" tongue and groove Drymax OSB. I offset the seams of the insulation and the plywood to keep the seams from having a common weak area. All of mine is glued down.

We are trying to keep the floor minimally thick as I'm 6'3. On top of the plywood we are putting 2mm underlayment and adding traffic master vinyl flooring. Do you think that will be adequate ?

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[Robin97396]

I don't know how flexible your other flooring materials are but I'd suggest thicker ply to make your floor solid. Tong and groove works well to keep the edges matching.

[bstewrat3]

I can only go by what I have done, but I would take away from the insulation thickness and add to the plywood. With your layers being thin I would try to avoid common seams. Maybe go with the 1/4" fan fold insulation and a 1/2" T&G plywood and use the same underlayment and vinyl. The adhesive I used is PL 300 which is specifically for foam insulation.

[ZedEx]

What would be the downside to screwing to the floor? I planned on going under the bus to coat all the screws that came through.

I can relate to the OP. Im 6'2" and concerned about going to crazy on floor height. Im ok with slouching while walking, but my wife is not. If I go above the stock floor height by even an inch, she will be in danger of hitting her head...

[superdave]

Originally Posted by ZedEx

What would be the downside to screwing to the floor? I planned on going under the bus to coat all the screws that came through.

I can relate to the OP. Im 6'2" and concerned about going to crazy on floor height. Im ok with slouching while walking, but my wife is not. If I go above the stock floor height by even an inch, she will be in danger of hitting her head...

there is no downside, just a different way of doing it

[ZedEx]

is it worth gluing down the rigid foam panels? or can they float until screwed down with the plywood?

[bstewrat3]

If you plan to screw them down, I wouldn't waste time gluing them. The only thing it may help with is avoiding the insulation squeak when things shift.

[Rusty]

IF you guys are desperate for height, spray foam the underside of floor 2" and just lay the plywood on the treated/sealed steel floor, Like BlueBird does from factory.

Or raise that roof ! I thought my wife was tall at 6'

[Brewerbob]

Originally Posted by Rusty

IF you guys are desperate for height, spray foam the underside of floor 2" and just lay the plywood on the treated/sealed steel floor, Like BlueBird does from factory.

Or raise that roof ! I thought my wife was tall at 6'

And hope like hell you never have to replace a fuel, brake, air line under the bus.

[ZedEx]

Originally Posted by Rusty

IF you guys are desperate for height, spray foam the underside of floor 2" and just lay the plywood on the treated/sealed steel floor, Like BlueBird does from factory.

Or raise that roof ! I thought my wife was tall at 6'

It's easy enough to isolate the wires and lines ahead of time. Im finding several examples online of people doing it to motor homes and campers. I also don't have air lines. Ill have to leave the spot over the fuel tank open though.
Is 2" necessary? I was thinking just 1".

[Brewerbob]

Originally Posted by ZedEx

It's easy enough to isolate the wires and lines ahead of time. Im finding several examples online of people doing it to motor homes and campers. I also don't have air lines. Ill have to leave the spot over the fuel tank open though.
Is 2" necessary? I was thinking just 1".

I have air lines, air tanks, and for some damn reason a front fuel tank in an RE bus. With the rust conversion about complete, I guess I need to start making some "hard" decisions. Hard in that once made and committed, it will be difficult to undo.

Should I move the tank to the rear and get rid of the hatch and filler neck up front? Should I spray foam the floor and then foam board over it? Should I do radiant heating? That will only get me to the point of a plywood floor. It's going to start to get expensive fast. Appliances, electrical system, etc.

[ZedEx]

Originally Posted by Brewerbob

I have air lines, air tanks, and for some damn reason a front fuel tank in an RE bus. With the rust conversion about complete, I guess I need to start making some "hard" decisions. Hard in that once made and committed, it will be difficult to undo.

Should I move the tank to the rear and get rid of the hatch and filler neck up front? Should I spray foam the floor and then foam board over it? Should I do radiant heating? That will only get me to the point of a plywood floor. It's going to start to get expensive fast. Appliances, electrical system, etc.

I hear ya. This is a super important step that you can't undo. We're just going to have to commit to something

[Brewerbob]

To this point I've just been farting around. Bought some lights, back up cameras, this and that kind of stuff that I can't even install yet. Welded a patch here and there. Slapped (sprayed) some paint on the outside. Did a terrible job masking.

Already screwing things up. I need to weld patches in the floor where the heater hoses went under the emergency door. Also need to finish the patch behind the driver's seat. Should have done that before treating the floor. I just wanted to get SOMETHING done so it looks like progress is being made. This time I think I'll just weld over the floor instead of trying to cut pieces to fit in the holes. The floor isn't exactly level anyway.

[ZedEx]

Originally Posted by Brewerbob

To this point I've just been farting around. Bought some lights, back up cameras, this and that kind of stuff that I can't even install yet. Welded a patch here and there. Slapped (sprayed) some paint on the outside. Did a terrible job masking.

Already screwing things up. I need to weld patches in the floor where the heater hoses went under the emergency door. Also need to finish the patch behind the driver's seat. Should have done that before treating the floor. I just wanted to get SOMETHING done so it looks like progress is being made. This time I think I'll just weld over the floor instead of trying to cut pieces to fit in the holes. The floor isn't exactly level anyway.

I did the exact same thing with my house Renos. Had to get little victories to motivate me and improve my mental state around the project.
So I should get the rust hole on my wheel well cleaned up and welded before treating the floor? I have a bunch of painted 26ga steel to cut up and flue down for the bolt holes. I'll undercoat them later with a rattle can

[Brewerbob]

Originally Posted by ZedEx

I did the exact same thing with my house Renos. Had to get little victories to motivate me and improve my mental state around the project.
So I should get the rust hole on my wheel well cleaned up and welded before treating the floor? I have a bunch of painted 26ga steel to cut up and flue down for the bolt holes. I'll undercoat them later with a rattle can

I don't want these "short cuts" to bite me in the as5 but I don't have a lot of self discipline or patience when I'm hot and sweaty. Should have bought a heat gun to help with getting chalking off the walls at the floors. Instead I'm scraping with a pry bar. I still have a few spots with chalking and even a couple of plywood splinters under there. It's at the corners of the wall and floor, it'll be covered up, and not seen. But by the very same token, that's where any moisture and rust will eventually be.

If I'm covering up the easy stuff already, what's it going to be like when I need to cut true 45° angles to build a cabinet?