Simple Subfloor Build?

kalabaddon · 03-06-2022, 10:05 PM

Hey all.

Just finished painting the floor of the van and now to install a subfloor. I am thinking super simple that I can replace a year or 2 down the road if I feel like it with minimal time and effort. ( not saying I want this to be cheap, or not last long, just easy to replaces if I decided to do something else and to keep my mind at ease while putting it together here and now. )

I have been reading a bit and came to the following conclusions, Can you all chime in on your experiences with these?

my plan is bare floor, 1/2 or 1 inch XPS or Polyiso , 1/2 ply, then a vinyl floor pattern and a few throw rugs here and there.

So anyways, my thoughts are as follows.

1. I think XPS is better for the floor from what I read, but I can not find 1/2 inch, only 1 inch, is it not available in 1/2? Right now I have a low roof so every inch matters, but that said I may just go with 1 inch however depending on what ya all say.

2. I do not need to glue, screw, or bolt it down. ( cept gluing the vinyl to the top of the plywood floor. )

3. No reason to fill in crevices on the stock floor. ( i.e. no furring strips if I got the term right?) people say the XPS/Polyiso is strong enugh to compression that it with the 1/2 ply should be fine and leave a place for water to drain in the crevices.

4. XPS or Polyiso 1/2 inch should be fine for the floor assuming I am chasing good weather somewhat (I will be in places that might have freezing nights or a few days of bad weather, but for the most part, will be south for winter and north for summer.)

5. Whatever I have not asked or do not know to ask! :P

Thanks all!

kalabaddon · 03-07-2022, 06:09 PM

Additional questions,
For bisket joins, I just use a router tool head right?
Is 1/2 ply thick enough for bisket joins?
And if I did my math right I will need 3 4x8 sheets for a extended econoline right? or to be closer I need just over 2 sheets?

kalabaddon · 03-07-2022, 07:34 PM

And it looks like I will be using Polyiso, I guess XPS is illegal in CA ( or something stupid, like no one carries it anymore anywhere.) and I dont wanna make a road trip just to install my floor.

BCam · 03-08-2022, 07:40 AM

Quote:

Originally Posted by kalabaddon

Additional questions,
For bisket joins, I just use a router tool head right?
Is 1/2 ply thick enough for bisket joins?
And if I did my math right I will need 3 4x8 sheets for a extended econoline right? or to be closer I need just over 2 sheets?

If you do a Google search, you'll see that it's definitely possible. The main drawback mentioned is that the biscuit might "telegraph" its shape so it's visible on the surface. This is a cosmetic issue that would only be a problem if your finish floor is going to be sheet vinyl or something similar. It wouldn't be a problem with laminate, another form of plank flooring or carpet.

You mention using a "router tool head". I don't think a router will have the accuracy necessary to do a decent job, especially on 1/2" plywood. You'll be much better of using a biscuit joining tool. I'm sure you could rent one.

Do you think that the biscuits are absolutely necessary? I'd think that edge gluing them with waterproof Titebond as you lay them down would be adequate. You could temporarily keep pieces aligned by screwing down a batten over the joint with plastic wrap between it and the plywood to avoid it getting stuck to the plywood.

kalabaddon · 03-08-2022, 04:06 PM

I have decided to have it free floating entirely, no glue or joins. I expect it will shift a bit but I am thinking to have it but up on the back of the metal seat rails and to the back of the van so it doesn't have any where to shift. But I like your idea of using a few battons on top of the ply to hold it tougher, that seems like a simple to work with idea!

Also decided on not getting any carpet or vinyl. just gonna toss some throw rugs over stuff and use the crud I put in van to hold it down in general. I have a lot of anxiety issues with doing permanent things and I am not in a great place right now so it is harder then normal for me to commit to something that will be hard to undo if I feel I did it wrong. By having it free floating I can get on the move that much sooner. This way a year down the road if I am feeling more up to it I can easily redesign the floor. ( or anything for that matter. ) since it will just all pull out.

I ended up going with 3/4 sande ply, and 1 inch polyiso. I figure if I am ducking to get around anyways 1 inch vs 1 3/4 inch is next to no difference.

gonna attempt to get it installed tomorrow. will show some pics of my scary work when done!

kalabaddon · 03-12-2022, 12:05 PM

So I did get the floor in, not super precise and a lot of wavy cuts LOL. but it fits snuggly and I can remove it easily.

Now that I did all that I decided to remove it easily and paint / seal the floor. What would you recommend as a water sealant for Sande ply? I have zero need for it to look nice, I am still planning on laying some carpet over it all, just figured why not add this extra layer of protection on the wood.

So that said what would be the easiest way to do this? They make a good spray on coating / varnish/ sealant? This would be just for day to day use, I am not planning to walk in van with soaked shoes or spraying water inside etc... Just want it to be safe from every day spills n drops.

Thanks all

BCam · 03-12-2022, 04:40 PM

Exterior grade, brush on polyurethane. No need to pay the premium for spray cans. And don't forget to seal the edges. Do a good job since I don't see that Sande Ply is external grade. Varathane makes a water based version which will simplify application and cleanup.

kalabaddon · 03-13-2022, 12:08 AM

Quote:

Originally Posted by BCam

Exterior grade, brush on polyurethane. No need to pay the premium for spray cans. And don't forget to seal the edges. Do a good job since I don't see that Sande Ply is external grade. Varathane makes a water based version which will simplify application and cleanup.

I google a bit and had a few questions. Water seems much easier all around with the quick drying times. You think one gallon would be enough, How many coats would you recommend? I am seeing up to 5+ but they seem to be going for really nice looking finishes that will be directly walked on, since this will mostly be under carpet or some other top layer can I just do 1 or 2, or do I need x amount to get a good seal? Would cheap foam brushes work? (I still have 6 from por 15 job I did)

Lastly any big difference on brands? my local stores tend to only have 2 gallon packs so I may need to get minwax from lowes instead, or one of the store brand water based polyurethane.

Sorry for all the questions, takes me a bit to get going on some things LOL.
Thanks

BCam · 03-13-2022, 07:31 AM

Quote:

Originally Posted by kalabaddon

I google a bit and had a few questions. Water seems much easier all around with the quick drying times. You think one gallon would be enough, How many coats would you recommend? I am seeing up to 5+ but they seem to be going for really nice looking finishes that will be directly walked on, since this will mostly be under carpet or some other top layer can I just do 1 or 2, or do I need x amount to get a good seal? Would cheap foam brushes work? (I still have 6 from por 15 job I did)

Lastly any big difference on brands? my local stores tend to only have 2 gallon packs so I may need to get minwax from lowes instead, or one of the store brand water based polyurethane.

Sorry for all the questions, takes me a bit to get going on some things LOL.
Thanks

I'm going to change my recommendation from water based exterior polyurethane to water-based exterior house paint, preferably in a satin or semigloss finish. You'll have a lot more choices and probably save money.

If you go the paint route, most stores like Home Depot and Lowes have discounted cans of paint that were color matched for a client and weren't right. You may also find that you can get partially used or even full cans of paint at a local county or city recycling center or at a Habitat for Humanity Restore if you have one in your area. You don't really care about the color so either of these sources would be my choice. In this case I'd pick up a gallon which will be more than enough and you may have other things to paint.

As far as your other questions:

1. Two coats should be fine, you won't be walking on it directly and you won't care how pretty it is.

2. Foam brushes or cheap bristle brushes are OK, as is a roller. Small brushes will take longer.

3. Store brands are fine and check the sq ft coverage to figure out how much you need. I believe the coverage stats are for one coat. A quart may be enough but, if you need two quarts, they're going to cost about as much as a gallon. This is another reason to go the salvaged paint route.

kalabaddon · 03-13-2022, 02:48 PM

@BCam, So got a full gallon of BEHR Multi-Surface Stain-Blocking Primer & Sealer for 9 dollars since someone had gotten it colored/tinted grey and didnt pick it up, its water based and dries in an hour so should be simple to work with. Thanks for the tips so far! gonna sand and paint by tomorrow hopefully.