Subfloor setups

[Elma]

I glued 3/8" plywood over 1/2" r-max. It bit me later on when I was gluing down cork flooring. Every seem was inconsistent. I think there is enough moisture that thin plywood will warp. If I could do it again, I would use t&g.

[Brewerbob]

Originally Posted by Elma

I glued 3/8" plywood over 1/2" r-max. It bit me later on when I was gluing down cork flooring. Every seem was inconsistent. I think there is enough moisture that thin plywood will warp. If I could do it again, I would use t&g.

I'm doing a roof raise so I don't need a thin floor. My "plan" such that it is, is to spray foam the floor to an inch or so. 2 or 2 1/2 inch foam board and route it out for pex radiant heat. 3/4" ply on top of that. Then something on top of that. I like the idea of real wood flooring but that's another 1/2" ~ 3/4". Don't care about the height but will the radiant work with 1 1/2" wood to go thru? If I do real wood, I can probably skip the ply altogether?

[Robin97396]

Bob, I still don't understand why you want to spray foam the floor. They make perfectly nice sheets of rigid insulation for that and it's so much cheaper.

My understanding was the only reason spray foam was worth the expense was because it would conform to the curves of the roof better than rigid insulation. Your floor is flatter than a pancake so why endure the expense of spray foam on a flat surface? You're essentially making your own rigid insulation from spray foam, but without the mylar.

After watching some of the vids about rigid insulation installations I've come to some new realizations about insulation. Next bus I will use rigid insulation in all the flat application areas, such as floors and walls. I'd still prefer spray insulation for the ceiling or other areas that are too difficult for rigid insulation. Even a small spray foam kit would do a decently thick coverage job if you only have to do the ceiling with it.

I'm not trying to argue with you. I just don't understand why you'd use expensive spray foam to, in effect, create rigid flat insulation.

[Brewerbob]

Originally Posted by Robin97396

Bob, I still don't understand why you want to spray foam the floor. They make perfectly nice sheets of rigid insulation for that and it's so much cheaper.

My understanding was the only reason spray foam was worth the expense was because it would conform to the curves of the roof better than rigid insulation. Your floor is flatter than a pancake so why endure the expense of spray foam on a flat surface? You're essentially making your own rigid insulation from spray foam, but without the mylar.

After watching some of the vids about rigid insulation installations I've come to some new realizations about insulation. Next bus I will use rigid insulation in all the flat application areas, such as floors and walls. I'd still prefer spray insulation for the ceiling or other areas that are too difficult for rigid insulation. Even a small spray foam kit would do a decently thick coverage job if you only have to do the ceiling with it.

I'm not trying to argue with you. I just don't understand why you'd use expensive spray foam to, in effect, create rigid flat insulation.

1) My floor is wavy and not even close to flat. That said it's probably flat "enough".
2) The biggest reason to spray foam the floor is to seal it. I want that sucker waterproof not mist proof. With all of the nail holes and bolt holes, I've yet to hear of a better way of sealing the floor 100%. Epoxy and pennies will miss the nail holes. Chalking will miss the nail holes. I have a couple of little rust spots that I didn't bother patching that aren't terribly big but are funny shapes. I may skip the foam board on top of spray foam and do just spray to 2" inches. The point of the foam board is to route it out for radiant heat.

I've lost where the thread is now but there was mention of a guy in IL that'll spray a bus for $800. Don't know how thick or the density of the foam but IL while not across the street is closer than OR. Guess I need to see how close I can get and be under $1000 or so.

[Robin97396]

I'm certainly not an expert on floors by any means. I've exposed my many mistakes.

You're basically talking about putting a $600 kit worth of insulation on your floor to be followed by rigid meant to hold your hydronic system? Two inch rigid would do the same thing in the neighborhood of $200, and without the leveling problems. No trimming.

I'm just going to have to be patient and learn something from your process. Unconventional thinking is what's making your build so interesting to follow. This story is unfolding so slowly, I just wish you'd hurry the heck up.

I'm learning stuff for my next bus.

[Brewerbob]

Originally Posted by Robin97396

I'm certainly not an expert on floors by any means. I've exposed my many mistakes.

You're basically talking about putting a $600 kit worth of insulation on your floor to be followed by rigid meant to hold your hydronic system? Two inch rigid would do the same thing in the neighborhood of $200, and without the leveling problems. No trimming.

I'm just going to have to be patient and learn something from your process. Unconventional thinking is what's making your build so interesting to follow. This story is unfolding so slowly, I just wish you'd hurry the heck up.

I'm learning stuff for my next bus.

Have you seen the video guy in NV that sprayed his floor? I don't know if he's on Skoolie or not. I'll wait until you answer before digging for the link. I have it semi handy so it isn't that big of a deal if you want it.

I'm not sure what he did between the spray and the plywood. He might have air gaps and just doesn't care. He doesn't have board nor radiant tho.

[Brewerbob]

P.S. You're one to talk about hurrying up with that six month paint job you've got going on.

[Robin97396]

How true. And now I'm back in the middle of a heat wave again.

It's odd at this age. I don't have much tolerance for heat or cold, and the east coast humidity is out of the question.

Lucky for me I'm not on a schedule. I am, however, getting more work done now than I was during the winter. It's supposed to be triple digit temperatures for about a week, which is unusual for this time of year. I'm thinking of going to higher elevations for a while.

[cadillackid]

why is it that everyone is getting awesome heat waves but us??? grrrr.. the hottest I can seem to get here is an occasional day thats 90 with 80% humidity... I miss the days when we had real summers...

even "rigid" insulation is going to conform to imperfections in the floors.. so "rolls" or "heaves" are goingto end up close to flat.. everything in a bus is like building on an old house.. you have to measure and cut to fir as you go... in theory it sounds awesome to be able to have perfectly square floors and corners so you can build cool cabinets in a shop and lift them into the bus.. but thats tough.. your best bet is to build nice square stuff but have variable wifth trim pieces to cover the gaps when you set things into the interior.. or be willing to cut and fit every single board you make.. ehich is super tedious if you are impatient..

the first time you move your bus 50 feet its going to be tweaked a different direction... vehicles are designed to flex to some extent... they arent completely rigid.. so trying to have a 100% square true floor is futile...

-Christopher

[Brewerbob]

Originally Posted by Robin97396

It's odd at this age. I don't have much tolerance for heat or cold, and the east coast humidity is out of the question.

You're preaching to the choir. Preach on Brother!!*

*But do realize I've lived almost all of my life on the east coast if we are going to swap war stories.

It's supposed to be triple digit temperatures for about a week, which is unusual for this time of year.

That happens where you are?!!? For a record single day temp fine and dandy but a week straight? If it's a common (yearly) occurrence, screw that!!

I'm thinking of going to higher elevations for a while.

That's generally a good idea regardless of temp. Now if the snow fall is being measured by the foot per hour then I might reconsider for the day/week.

[Brewerbob]

Originally Posted by cadillackid

the first time you move your bus 50 feet its going to be tweaked a different direction... vehicles are designed to flex to some extent... they arent completely rigid.. so trying to have a 100% square true floor is futile...

-Christopher

My floor is way off in that I would never consider adding flooring directly to the metal. Not that I'd want to but even tongue and grove wouldn't be level and may buckle. Valley to peak might be 1/2".

I've not looked closely at the walls yet.

[Brewerbob]

Originally Posted by cadillackid

why is it that everyone is getting awesome heat waves but us??? grrrr.. the hottest I can seem to get here is an occasional day thats 90 with 80% humidity... I miss the days when we had real summers...

-Christopher

Go eat a cheeseburger but otherwise shut your mouth!!! The only awesome summer is the one that doesn't break 72°. I'm batting 0 of 48 on awesome summers.

[Robin97396]

It even gets hot in Alaska for a couple days.

That's why here in Oregon many of us don't bother with AC. The hot weather never seems to last more than a couple weeks. It's not hard to duck the heat for that long, and there can be a lot of expense in keeping the AC running over a period of years.

[Rusty]

Originally Posted by Brewerbob

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

Fuel and air lines are on the inner frame rail on my bus, foam is higher- between floor ribs above frame.

If you have tanks for water, foam those too.

[Brewerbob]

Originally Posted by Robin97396

It even gets hot in Alaska for a couple days.

[Frist World Problems]I might could suffer thru it for 72 hrs but a full week would be too much.[F.W.P.]

Originally Posted by Rusty

Fuel and air lines are on the inner frame rail on my bus, foam is higher- between floor ribs above frame.

If you have tanks for water, foam those too.

Mine seem to be about mid frame I think. I'd have to get back under there and take a look again. Around the air tanks and diff would be tricky to spray just because of wand angle if nothing else. Might could be worth the effort tho. Especially if I do a floor raise. Seal it from below. Foam board from above and glued for any missed nail holes. That will leave the under floor storage nice and flat.

I don't have any tanks except fuel at the moment but thx for the idea.

[ZedEx]

Sorry to derail the discussion, but I found this rubberized asphalt stuff by the gallon and it seems perfect to seal the metal before laying the plywood on. Even adds some sound proofing apparently. Could definetley use some of that.
https://www.dominionsureseal.com/pro...ating-sufsufv/

The only problem is that I wanted to construction glue my plywood down instead of screws through the floor. think this stuff will cause adhesion issues?

[family wagon]

If sealing of the floor is the main reason for spraying foam you might also consider a "pedestrian traffic coating" such as Vulkem 351.

Originally Posted by Vulkem 350/351 Data Sheet

Vulkem® 350/351 is a composite waterproofing system comprised of tough-curing liquid polyurethane. It cures to form a rubber membrane surface that provides a lasting and easy-to-clean coating. Textured surfaces for pedestrian traffic will use an aggregate-laden top membrane to aid in wear and slip resistance. Vulkem 350/351 may be used to apply a seamless, monolithic waterproof membrane to concrete and primed metal surfaces.

I've used it as a coating over outdoor wooden decks in a residential setting. It's not the cheapest stuff, so how it compares in cost to lay this down followed by foam board versus simply spraying full-depth foam I'm not sure. Tremco also makes caulks also under their Vulkem name which might be appropriate for sealing every little nail hole individually rather than rolling a coat across the entire floor.

[Brewerbob]

Originally Posted by family wagon

If sealing of the floor is the main reason for spraying foam you might also consider a "pedestrian traffic coating" such as Vulkem 351.


I've used it as a coating over outdoor wooden decks in a residential setting. It's not the cheapest stuff, so how it compares in cost to lay this down followed by foam board versus simply spraying full-depth foam I'm not sure. Tremco also makes caulks also under their Vulkem name which might be appropriate for sealing every little nail hole individually rather than rolling a coat across the entire floor.

It'll work for teh nail holes but then so will a smashed gnat's as5. What about the bolt holes? Those are bigger and depending on how liquid this stuff is...

[family wagon]

The edges around the wooden decks I mentioned earlier are created by forming a dam with duct tape wrapped around the perimeter. The stuff is definitely thinner than gelatin, but it doesn't take much tape strength to hold it in for a few hours while the product sets. Bolt holes could be taped on the underside, product applied on the top side, and so long as the tape can hang on for an hour or two the product will remain in place sealing over the hole.

[Brewerbob]

Originally Posted by family wagon

The edges around the wooden decks I mentioned earlier are created by forming a dam with duct tape wrapped around the perimeter. The stuff is definitely thinner than gelatin, but it doesn't take much tape strength to hold it in for a few hours while the product sets. Bolt holes could be taped on the underside, product applied on the top side, and so long as the tape can hang on for an hour or two the product will remain in place sealing over the hole.

That's problematic for a number of reasons. 1) I'm not sure the tape would stick to whatever dirt and grime is under there 2) Can I reach them all? 3) I missed one.