Subfloor Design and Material..?

[Diesel Hansel]

Subfloor..

This topic has been addressed a few times, but there is not an enormous amount of light shed on the subject.. as far as my search went. I may just be an incompetent searcher.

In the last two days, I completely gutted the interior of my 82' diesel Westy. This is my first time seeing what is exactly beneath everything. I meticulously bagged and tagged all of the hardware and components. So far I have dealt with the minor rust, by removing it and painting it with a rust inhibitor and primer.. as well as dealing with some other things, re-grounding, replacing bits of insulation, deep cleaning, etc. Now it is time to put it all back together. I plan on putting down insulation strips in the recesses of the floor, a subfloor, and reclaimed oak from wine barrels (planed to about an 1/8" thick)

So my questions about the Subfloor are:

1. Is there a reason my old subfloor was a main piece under in the center, with a separate piece under the rear seat, a separate piece under the water cabinet, and a separate piece under the fridge/stove unit?

2. The main piece was 1/4" ply, and the others were 1/4" of some type of other material (felt like the back side of hardboard on both sides) -- Is there a significance to that material (maybe its ability to absorb leaked water, so that it does not build up in the seam of the body)?

3. Would it make sense to lay the subfloor, then lay the reclaimed wood completely over it, then install the cabinets? Or should I lay the subfloor, then install the cabinets, then install the reclaimed wood floor (barely tucking under the cabinets)?

4. Should I lay some sort of protective layer under the water cabinet (just incase a leak occurs)?

The reason these questions are troubling me is because to me it makes sense that the floor's thickness must be the same as the raised bolt holes on the floor of the car. This ensures the cabinet holes/bolts on the sides will line up so they can be bolted together to the back closet. The previous owner just shoved the ends of the bamboo tongue and groove flooring under the front of the cabinets and back seat (in my mind this doesn't make sense because the bottoms of the cabinets should be bolted flush with its subfloor. Wish I would have taken detailed pictures of it before, like I did on the rest of the removal.

Any info on this would be wonderful.

In my mind what would make sense is this:

First put down the insulation strips. Then lay one piece of 3/8" down under the water cabinet and stove/fridge unit (about 1/4" short of the front edge of the cabinets) . Then lay one piece of 1/4" down on the main floor and under the back seat (instead of two separate), and 1/4" under the front of the cabinets ). Next lay the 1/8" oak (with liquid nails) onto the entire 1/4" ply, thus bringing its height to 3/8".. Leaving everything nice and even at 3/8", and having the wood floor continue into the bottom of the back seat storage and go 1/4" under the front of the cabinets. Also having a separate piece under the water and fridge incase it ever gets wet and needs to be replaced.

Sorry for the lengthy post, I just really want to make sure I presented all the info, so I can get some clear cut answers from you seasoned pros out there. I really want to put the guts back in so I can get out on the road again.

[61Scout]

Hello and welcome! Sorry no one got to you yesterday!

I don't have a full camper, but I'll give it a shot...

1 and 2. It would be far easier for servicing the center (if you had to at one point) by keeping the pieces separate, and for repair as you mentioned. That said, on my weekender it's one piece across to the wall since I don't have the fridge/sink. The other reason I'd guess they did that was that wood is more expensive than fiberboard and also perhaps heavier. Saving weight saves fuel. If you're not standing on those areas there's no need for wood to be there to support your weight.

3. I'd personally run the sub and final floor under everything. Though, having never done this I can't say whether that would interfere with install of fasteners being too short and everything else lining up properly. Sounds like you had the same concerns. Hopefully someone who has played around with their floor more will chime in soon.

4. I wouldn't put any protective layer in place. But I would cover any exposed wood to prevent any warping/distortion. A good oil based primer would work I'd think.

Now hopefully that gives this thread a bump and finds you some answers. Good luck, and again welcome.

-Kevin
_________________
1986 Westfalia Weekender Wolfsburg, RJE 2.3
1985 Tin Top, Subie 2.2 + 5MT
Floppy Mirrors no more: http://www.thesamba.com/vw/forum/viewtopic.php?t=653018&highlight=
Remove the front spindle nut with ease: https://www.thesamba.com/vw/forum/viewtopic.php?t=679567&highlight=
Remove the rear wheel bearing housing without messing with the big 46mm nut: https://www.thesamba.com/vw/forum/viewtopic.php?t=679507&highlight=

-Nec Spe, Nec Metu

[Diesel Hansel]

Thanks for trying to kickstart this thread for me Kevin.

I completely agree with the idea that keeping separate pieces makes servicing the center a much easier job. As far as the the fiberboard goes, I never thought about the idea that it could be cost and weight that determined the material, but once again, it makes sense. I still wonder if its absorbency plays a roll in keeping that rust seam at bay (though it would probably increase the mold/mildew factor).

When you say "exposed wood", are you referring to just the top layer of oak I am putting down that's surface is exposed, or are you also talking about the subfloor plywood as well? It makes sense to me that a coat of primer on the ply would help with the mildew I found on the old sub-flooring I tore out.

One thing I figured out today that I missed earlier is that the front edge of the cabinets are actually 1/8"-1/4" above the part that sits flush with the subfloor.. So tucking the top layer of oak under the lip of the cabinets ( the way the pergo I removed was installed) suddenly makes sense.

Thanks again for getting this thread started. While browsing through past threads on here for the last few weeks, I have come across quite a few of your posts that have some very useful information. Hopefully this thread will get a few more responses soon.. In the mean time I have all of the shrunken, wrinkled contact paper to replace with cork inside of the cabinets and shelves.

I will post pictures when I get around to the install.

If someone has a picture of a factory subfloor, that would be a great reference... Or any other info regarding material choices for the subfloor under the sink/stove and water cabinet that would great.
_________________
1982 Diesel Vanagon
1.9 N/A
68 Horse Power

1983 XR200R
11.8 Horse Power

1977 Motobecane Mobylette
2 Horse Power

1950's Grumman 17'
1 Man Power

1971 Bus (RIP)

Add them all up, and I am getting close to 100 HP

[PDXWesty]

Installing the subfloor in pieces then the flooring under everything defeats the purpose of installing the subfloor in pieces. The original flooring rubber mat only covered the center open area. I would keep it the same for any other flooring.
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89 Westy 2.1 Auto

[dobryan]

I would install your subfloor so it has an independent center section. That way if you ever need to gain access the metal floor in the center you will not need to remove any cabinets. Same goes for the final flooring as well.

I'd keep the total thickness of your final floor system the same as stock where it is under the cabinets in order to be sure that the bolts and fasteners all line up as intended.
_________________
Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[Diesel Hansel]

So here is what I ended up doing:

I removed the 4 old subfloor pieces.

I then scrubbed with simple green and blue scotch-brite, and dealt with the minor rust..steel wool, primer, clear coat.

I traced the piece under the sink, and made a new one with 3/8 ACX (exterior) plywood. Then sealed it with 3 coats of waterproofing (helmsman I believe). (the cuts are not pretty.. Was using a jig saw around 50 years old, that wasn't the problem though..the 50 year old blade was. Replaced that before I moved on the paneling in the van.)

I removed the plastic material from the bottom of the piece under the clean water tank, sanded lightly, then covered with waterproof Aluminum tape.

Next I took the old main piece, and the piece under the bench seat, placed them together, and traced. I cut out one large piece, instead of two. To me this seems more secure, as the bench actually holds the whole piece down (opposed to the 6 screws going down into the sheet metal (probably from the previous owner, and not the original method..but maybe). I then coated this piece with 3 coats of waterproofing.

But before I installed all this new wood, I put in some strips of reflectix, and aluminum tape down to help fill the gaps, as well as help insulate.

So in the end I went with 3/8" for everything. (Under the water tank it is actually 1/4"ish..but there are two strips of 1/8" on top.. I believe to make a small gap so if there is a problem with the water tank, it will not make the bottom of the cabinet soggy)
I combined the 4 pieces into 3.
I insulated the recessed grooves on the floor.
And waterproofed everything with either a sealant, or aluminum tape.

When put back together the floor has almost no sag in the grooves, it makes no noise, as it is secured down very well, and it will not get moldy like the last one, even if water does find its way down there, because it will not absorb the water.

Also, I figured out very soon after posting my original response that you do not have to worry about the top layer of wood when installing this way, it just has its edges tucked under the cabinets and rear bench, so it makes a nice clean install.
_________________
1982 Diesel Vanagon
1.9 N/A
68 Horse Power

1983 XR200R
11.8 Horse Power

1977 Motobecane Mobylette
2 Horse Power

1950's Grumman 17'
1 Man Power

1971 Bus (RIP)

Add them all up, and I am getting close to 100 HP

[dobryan]

Very nice!
_________________
Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[MattBenson]

Very cool! I am planning on starting this same project this weekend in addition to removing the fiberglass bat insulation behind the kitchen. Thanks for the info and documentation. I'd love to see some images of the finished project with everything reinstalled if you have any!

[Steve M.]

"Thompson's Water Seal" is a good protector for the bare wood if you leave it bare.

I think I saw on the "The 16" Money Pit" thread where he used the foam tubing pipe insulation used on water pipes to replace the original fiberglass insulation in the walls.
It is closed cell foam and not going to soak up water. I saw an image where he had it the tubes running vertically. Packed snugly and it's going to be a great temp insulation and probably sound as well.

[Elliott]

[R0Batt]

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85 Westy

Charlotte, NC

[R0Batt]

I'm curious about using an XPS board instead of wood for the subfloor

XPS is lighter and provides better insulation
however, it doesn't block as much air-born road noise because it is not as dense.

Any thoughts?
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85 Westy

Charlotte, NC