Don’t Lay Subfloor Before Roof Raise: Separating Loctite PL3 Wood From Pink Foam?

[Nick5272]

TL;DR my floating 3/4” subfloor is warped from being rained on during the roof raise. Not sure it’s fixable. Is there a way to demo just the wood without destroying the Pink foam board? Other ideas?


As the title suggests, I’m debating what will be a major set back in the build: redoing my subfloor. I could not find any other thread on here detailing this process so if I missed it please point me there. My floor is designed like Chuck cassady’s method with the 2” pink foam board held to the floor with loctite pl. On top of that is the 3/4” T&G plywood. Some of the T&G didn’t fully interlock though when first installing so it’s begun to rise in a couple places. I gave up on the floating concept at that point and went to bolt down some areas in the back with 3/8” 5” steel bolts and large washers with nylock nuts. I routed out a recess so they sat flush with the floor. The plan was to fill the recess and cover the bolt with something of higher r value. Bolting only seemed to worsen the warps though by letting another area rise as the first area got bolted down. I guess I’d need to do a complete grid of bolts if I hope to flatten the floor. I just hate that it’s not flat but it’ll be so hard to redo the whole thing. So what are y’all’s suggestions?

If you do think I should demo and redo, is there any way to preserve the pink board? That stuff was expensive and I really don’t want to have to buy it again. Also what would you say is the best method for separating the wood from foam that’s secured with PL3?

Thanks in advance

[TucsonAZ]

Originally Posted by Nick5272

Bolting only seemed to worsen the warps though by letting another area rise as the first area got bolted down. I guess I’d need to do a complete grid of bolts if I hope to flatten the floor. I just hate that it’s not flat but it’ll be so hard to redo the whole thing. So what are y’all’s suggestions?

If you do think I should demo and redo, is there any way to preserve the pink board? That stuff was expensive and I really don’t want to have to buy it again. Also what would you say is the best method for separating the wood from foam that’s secured with PL3?

Thanks in advance

If this were me, I would certainly try to turn this into a positive, if you stand on it does it flatten out? One way of doing something that may work to your advantage is to add another 3/4 player of flooring over what you have, potentially in the other direction. Put a ton of weight on it and hope it flattens out the layer below and adheres flat. If the top plywood has high spots from swelling with the water, you could do as mentioned after belt sanding it as good as you can.

You could also do something like a TnG pine flooring over it instead of my plywood but I can't see it so that's just a guess but I would generally head in that direction of covering to flatten.

Sorry that happened, I spent the entire day today just correcting an issue that would have never happened had I left an 1/8th inch of additional space, seriously frustrating!

[TucsonAZ]

Originally Posted by Nick5272

Thanks in advance

Also, since we seem to be going down the same path if you ever want to phone talk and brainstorm or double check each others plans DM me your number and a good time that you're normally free and we can talk more.

[TJones]

You could use a grid of self tapping counter sunk stainless steel screws. You would have to predrill the bus floor first.

Ted

[DeMac]

Nick5273, I appreciate your delima, I feel for you. I'm greatful that you've shared you're experience with us. The thread's title and your testimonial may help others decide to wait on the floors.
For these folks, I add my two pennys...


Many skoolie builders install floors, directly after the interior demo. The floors can wait until nearly the end. Accidents happen on every jobsite.


steel floors

Like most builders, we demo'ed the floors, walls & ceiling. Basic Ospho & paint, then sealed the penetrations on the roof and cord connected a rooftop AC.

We worked in the cool from there, continued patching warning lights, resealing each window and covering floor holes. I framed the ceiling, completed the lighting & installed the electric panel.

No flooring is required to build most of the framing. Even the wall holding the 120v panel required only one Sill Plate.


Painted sill plate attached topside using Dynatron550


& from underneath using several 1.5" Simpson SD framing screws & fender washers, through predrilled holes





permanently leveraged/loaded

Laying on the 'bathroom' floor⤵


A builder could accomplish a great deal of sealing work and ceiling work, exterior walls, plus electric & plumbing... prior to risking any time or expense on floor materials.



I continue to seek out stormy weather as opportunities to occupy our build. Like a madman, wiping TP under the windows, in search of leaks.


Camping in the 'bathroom'

Still have only one 2x4 attached to the floor. Exterior walls next, eventually install some flooring, after insulating everything else.

[Nick5272]

Tucson, I appreciate the offer to connect. It’s a real busy season at work currently but I will be more free in a couple months and would love to. Definitely keep posting about yours too so I can see how it’s going.

Prior to the roof raise when we first laid the floor and there were some uneven patches (particularly the T@G seams) I used an electric hand planer to smith those down more flush with the rest. That may be what I wind up doing here again as well. That was finished off with some 120 on the big ol makita belt sander. I’ll likely do that whole process again once we’re done skinning.

One thing I failed to mention (and often forget) is that we put fiberglass mat and Bondo over all the seat bolt holes in the very beginning. I went back and sanded them down some but found that I couldn’t sand very far without reexposing the hole and defeating the purpose. We then painted over the Bondo with rustoleum. This made for a grid of very tiny humps across the floor where the Bondo made little mounds over the holes. My hope was that in weighing down the pink foam with 10 60lb sand bags it’d compress over those mounds enough to be more or less flat. Unfortunately, I never verified that and I’m afraid that’s what’s largely contributed to the warping now as well. I plan on making another warning post about that later

[Nick5272]

Demac, thanks again for the valuable input. It took me a second to follow what you were saying but to make sure I’m with you: you’re driving framing screws vertically up through the floor to put the framing pieces on? This is the first I’ve heard of a sill plate so that is not familiar to me.

I trust your knowledge and experience, but this method stood out to me since (as far as I’ve journeyed at least) you’re the only one I’ve seen do this. My knee jerk questions for ya are:
1. Do you not worry about mold or rot on the pieces that are touching the bare metal floor and have the screws from the exterior running up into them? Won’t they condensate and introduce moisture to the wood?
2. Won’t this create an incredibly difficult geometry to cut your subfloor pieces around? Besides protecting the subfloor itself, what other pros are there to this method?
3. Probably should’ve asked this first, but what are you doing for subfloor and insulation? Pink foam and plywood or something else?

I relate strongly to the wiping TP like a madman comment lol. Don’t feel like you’ve gotta answer all these either, this method just caught me off guard! Brand spanking new in my mind. Thanks!

[cadillackid]

seems like in a bus.. even one you seal up and test that its sealed up, youd use marine grade plywood so if in the future you do get a leak it doesnt ruin things right off.. marine plywood wouldve shrugged off the rain during roof raise.. I think unless you glued it down id pull it all and replace with marine.. id be concerned about hidden mold within the wood since its been wet enough to warp

[Nick5272]

I think unless you glued it down id pull it all and replace with marine

I did glue it down….with Loctite PL3. So thats brought me to this point of not knowing how to redo it while also preserving the foam board. Cadillac, do you have any more thoughts given that factor?

[DeMac]

Originally Posted by Nick5272

Demac, thanks again for the valuable input. It took me a second to follow what you were saying but to make sure I’m with you: you’re driving framing screws vertically up through the floor to put the framing pieces on? This is the first I’ve heard of a sill plate so that is not familiar to me.

I trust your knowledge and experience, but this method stood out to me since (as far as I’ve journeyed at least) you’re the only one I’ve seen do this. My knee jerk questions for ya are:

1. Do you not worry about mold or rot on the pieces that are touching the bare metal floor and have the screws from the exterior running up into them? Won’t they condensate and introduce moisture to the wood?
2. Won’t this create an incredibly difficult geometry to cut your subfloor pieces around? Besides protecting the subfloor itself, what other pros are there to this method?
3. Probably should’ve asked this first, but what are you doing for subfloor and insulation? Pink foam and plywood or something else?

I relate strongly to the wiping TP like a madman comment lol. Don’t feel like you’ve gotta answer all these either, this method just caught me off guard! Brand spanking new in my mind. Thanks!

------------------------------

Screws are not hypodermic. Condensation requires moist air and two temperatures.
Radiation, Convection &/or Conduction generates the temperature fluctuations.

Only the exterior facing screw heads are exposed & to a single air temperature. Sweaty head outside is the only possibility, but ought not, unless the interior lumber is icy cold.

Here in Hot, Wet, Florida, the condensation occurs, on single pane glass, OUTSIDE of cold AC homes.

----------------

For mold, mildew & moisture, I sealed the Building Envelope before installing any wood.

But also...


On the first morning, we applied exterior paint to five sides the sill plate, drilled the steel & later attached the painted side down.


The following morning, I added two coats of exterior paint to the up-facing sides, then left the fans on it for a few hours.






The second 2x4, the Sole Plate, is attached to the first using 2-1/2" 9 Simpson SD Connector Screws & fender washers.



The top of the wall is attached in the same two-layer fashion.


Since sealing the shell, two years ago, I've not had any moist air or condensation. No mosquitoes, bugs or ants may enter. It's my every day farm shop. Even my 🎄 dries out overnight.


In my experience, that is how most buildings are built:
Dry roof, interior framing, mechanicals(HVAC, electric, plumbing), wrap & windows (dry-in), drywall, cabinets, paint and finally fixtures & finish floors (about the same time). Meanwhile, tools, sharp objects, leaks, spills & boots gravitate to one place, only.

[cadillackid]

the glue makes it tougher unless enough water got in to cause the bond from glue to wood to fail..



at that point I would make the decision based on the use case of the bus.. if its going to be a full-time home where gambling with the idea of mold or warpage has a lot higher stakes vs if its a weekend wariror RV..


if its an RV and you realized by keeping the existing wood and fastening it back down that you have mold or issues.. you can tear it down and are sikmply inconvenienced by not taking camping trips..



if it is going to be a full time home where making a repair would mean renting a place to live and finding a place to rebuild.. then id probably bite the bullet and pull the floor apart even if it meant replacing the insulation board.. simply because the cost in time and $$ of a rebuild on the road would be much higher..