Redoing the floor of my van

[iplayguitarintheshower]

Hey All

So im tearing out the old carpet in my conversion van. 94 GMC Vandura 2500. The installer, whomever it was, did a half assed job. The window sills are held up with pieces of 2x4 snugged up against the body panels and insulation. its a fucking joke.

Anyway, I got the walling removed (mostly felt on plywood) to get at the carpet and underlayment polyiso boards. I dont see any sign of actual plywood...The carpet was on top a 1/8'' foam which sat on top of the 1/2 '' polyiso boarding then the sheet metal below it.

I'm going to rip out the existing polyiso boarding as its half stuck with carpet backing and 1/8'' in foaming. Going to install vinyl peel n stick flooring. For that, I need a smooth clean surface..

MY QUESTION!

What should the order be for new flooring? I'm guessing..

1. van body 
2. Insulation inbetween the body ribs to even out the surface / Polyiso boards broken into thin planks (better for venting?)
3. Foam backed reflective heat/sound insulation (shiny side up) 
4. Underlayment (either void free osb plywood, luna, or perhaps the polyiso board)
5. Vinyl Planks

Is this correct? Whos done flooring before on a van and can weigh in on this?
Do I need polyiso if i use a void free plywood or luna board?

Id be using the peel and stick vinyl planks of 6'' x 36'' most likely (Allure) that claim they dont require a subfloor (Shrugs)

 

[Optimistic Paranoid]

I haven't tried using peel n stick flooring myself, but we've had a number of posts here that suggest it doesn't work well in vans.  It was designed for use in houses, where the temperature stays in a fairly narrow range.  In a van, you can get temperatures well north of 100 degrees on hot, sunny days, and temps below freezing in the winter, and the peel n stick just doesn't seem to cope with that kind of range.

 

[Almost There]

The claim that the Allure peel and stick doesn't need any underlay is for use in a S&B where there is already a subfloor. Underlay in s&b is typically 1/4" plywood laid over top of the subfloor.

Instead of using peel and stick, which as OP pointed out has problems with drastic temperature changes in vans that it doesn't encounter in a traditional housing use, use the click together planking. I recommend vinyl over hardwood since it deals really well with spills and coming in with wet dripping clothing, muddy shoes, etc.

I didn't bother with any kind of insulation on the floor. IMO there is no need to fill in the ribs and reflectix or polyiso will only crush anyways under the weight of you walking around on it or the weight of stuff stored under the bed etc.

I used 3/4" plywood so that it was thick enough for me to safely sink screws in to to hold all the cabinets and bed frame etc. in place without the screws going in to the metal floor. It is also thick enough that it doesn't warp over the ribbed metal floor. The air gaps don't matter, it's dead air.

The only reason I can see to insulate a floor would be if you're going to be living in northern colder climes all year, then you want an insulated floor!! The only real way to do this is to lay out a frame of say 1 x2s and insert insulation in the cavities you created. On the flat you could put 3/4" of insulation, on their sides, twice that. Then cover the insulation with at least 5/8" plywood (any thinner will warp - badly) and then your finished flooring. Keep in mind what you're losing in head room for whatever you're putting on the floor.

 

[iplayguitarintheshower]

Why lay out a frame of 1x2? I have bolts in the body of the van that I need to access for the seats and this would create an unrealistic height from said bolts. The ribs in the sheet metal act as that frame anyway based on what youre saying.

I am not building custom cabinets. This is a conversion van. not a camper or stealth camper. I just need to bold the seats back in properly in the existing space.

Perhaps ill do the jean material backed insulation with 5/8'' plywood on top of that. I dont have a saw to cut though so thats a problem.

Also a floating floor isnt ideal in a van. I want the floor to be secure, so click and lock style vinyl that isn't engineered for glue down applications wont work. I dont want a floor sliding around, considering you need breather gaps along the sidewalls too

 

[WanderLoveJosh]

We literally just laid down peel and stick panels last night, so I can't say how well it's going to hold up.. However we also used extra adhesive called Tec indoor barrier.. Many people recommended it for the planks saying it def strengthens the hold... I guess we will find out.. Didn't take much time or cost much.

 

[offgridder]

The claim that the Allure peel and stick doesn't need any underlay is for use in a S&B where there is already a subfloor. Underlay in s&b is typically 1/4" plywood laid over top of the subfloor.

Instead of using peel and stick, which as OP pointed out has problems with drastic temperature changes in vans that it doesn't encounter in a traditional housing use, use the click together planking. I recommend vinyl over hardwood since it deals really well with spills and coming in with wet dripping clothing, muddy shoes, etc.

I didn't bother with any kind of insulation on the floor. IMO there is no need to fill in the ribs and reflectix or polyiso will only crush anyways under the weight of you walking around on it or the weight of stuff stored under the bed etc.

I used 3/4" plywood so that it was thick enough for me to safely sink screws in to to hold all the cabinets and bed frame etc. in place without the screws going in to the metal floor. It is also thick enough that it doesn't warp over the ribbed metal floor. The air gaps don't matter, it's dead air.

The only reason I can see to insulate a floor would be if you're going to be living in northern colder climes all year, then you want an insulated floor!! The only real way to do this is to lay out a frame of say 1 x2s and insert insulation in the cavities you created. On the flat you could put 3/4" of insulation, on their sides, twice that. Then cover the insulation with at least 5/8" plywood (any thinner will warp - badly) and then your finished flooring. Keep in mind what you're losing in head room for whatever you're putting on the floor.

 Why would the plywood warp? I am planning on installing 1/2" plywood in my van. Even though it may not be thick enough to fasten framing to securely, it is thick enough to walk on without warping if you just level the floor. I already installed strips of polyiso insulation in between the ribs. 1/2" plywood on top. 3/4" and thicker just weighs too much. Also, at 6'0 headroom is precious space. I plan on doing a free floating floor and strapping down the bed and cabinet framing to it. I can secure the framing to the floor with L brackets for added support but the main thing holding it down will be the straps: install D-ring tie downs to the metal floor in four corners or wherever needed and tie the straps to them, wrapping straps around framing. I plan to stay mostly in warm climates but do intend to visit mountains also so it needs to be ready for freezing temps.

my (intended) floor layers:

-1/2" polyiso strips between ribs (either glued down or free-floating, i'm not sure which is best)
-1/2" plywood (good quality)
-some vinyl flooring as a finish layer, easy to clean and spillproof.
This is my first build and just my personal preference on how to do the floor. I would be happy to hear people's comments/suggestions about this topic which has kept many a dweller up at night.

 

[MazdaGuy15]

I agree its not worth the space that the insulation takes up to properly insulate the floor. I don't plan to insulate the floor when I build mine out and I'm gona full time in Minnesota. I plan to put down a nice thick wool rug and wear slippers in the winter. If I was going to put anything down it would probably be reflectix shiny side down to try and keep the hot pavement from radiation up in the summer time.

 

[DrJean]

Well I don't feel so concerned about my floor install now. ROFL.
I put Prodex under the padded rubber mat, then 1/8" hardboard (painted with water proofing) and then vinyl/linoleum faux travertine.

I didn't want the really hard floor and since the underlayment floats, if I go with a true buildout of cabinets and bath area, the 1/2" or so can be put in. I need a softer floor to walk upon, but something with stability. (Didn't have the hardboard nor linoleum when I went to RTR).