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Old 08-24-2016, 11:50 AM   #1
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Does floor NEED inaulation

Had a really interesting talk with somebody who said they had a hard time with the snap-together floating floor on their bus. The movement caused the floor to lift. We had originally planned on not doing furring strips, but floating our floor directly on very firm insulation, but we aren't as confident it won't dent the insulation or cause to much give so the floor comes apart.

Heat rises, so essentially we feel that the floor does not lose much heat, and rugs and socks can help with cold feet. The height lost will be put into insulating a ceiling, for we don't want to lose height both directions. We are also super insulating the walls, and running rigid foam UNDERNEATH the bus, instead of the floor. He suggested just gluing The floor onto the metal, but we want a vapor barrier....has anybody done something like this? We don't feel we have the time or resources to do furring strips, nor do we want to lose 3 inches of floor and not have room to insulate the ceiling...
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Old 08-24-2016, 01:01 PM   #2
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We did not change the stock insulation at all in our bus. It does not hold heat well but that is due to the windows, not the floor. Our floor is metal, then we put down vapor barrier and then the thin base foam (can't remember the name of it) that goes under normal laminate snap together flooring. Half of our floor is snap together laminate maple, and half of it is stick on black and white vinyl tile on top of a sheet of luan on top of the aforementioned vapor barrier and foam. I think putting your foam board under the bus will be great for insulation, just make sure it's sealed well so wet from the road can't get in it and make it heavy and moldy and rusty. We've been on the road with our flooring for over 15,000 miles and haven't had a problem. It's not even secured to anything and it doesn't even go all the way to the walls. We just screwed our furniture right down into the floor and that also holds the floor from sliding around without inhibiting the "floating" aspect. And we bought the cheapest (<$1/ft) flooring Lowes carried! Even with no insulation it's basically no different than walking on wood flooring in an old house. Yeah, it's cold but I don't care how much insulation you pack on your bus, if the windows are still there it won't hold heat. We're ok with that and would rather keep our windows and save money on insulation.
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Old 08-24-2016, 01:54 PM   #3
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SmujnStar, As you pointed out, heat rises. You'd be surprised at just how much heat will enter your bus from the floor. Even with the 2" of foam under my bus floor I still see a big climb in interior temps when I park on an asphalt parking lot late in the afternoon. Remember, insulation works in both directions. Installing the under floor insulation was a PITA but I'm sure glad I did. Jack
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Old 08-24-2016, 06:27 PM   #4
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I plan on going the insulation underside route.
A floating floor is exactly that.
If you read the directions it says to cut it 1/8? Short to allow room for expansion and contraction and the trim boards to be installed in the same manner for the same reasons.
I did the whole floating floor in my house before I did my bus.
There are areas in my house that I cut to tight and when we go from AC to windows open the floor likes to bow/buckle in places.
I would think that in a moving platform that you would want to leave even more wiggle room to accommodate the floating in the floor.
To be a thick quarter round or make your own trim is needed.
I built every wall, or whatever to securely fasten directly to the steel floor so all of my spaces are floored separately to wiggle as needed and that's why I decided to insulate underside instead of inside. I used 1/4" foam for most and and little bit of some carpet underlay that was fibre material with plastic for around the transmission motor area? Trying to deaden the sound a little.
Hope this helps.
Sorry another option I just started daydreaming about was clean/prep and spray foaming the underside?
It would be easier and maybe cheaper before you put a lot of mess in the way.
I do commercial construction and see them spray galvanized metal and they can do a 3" spray on the backer board the steel I-beam then to the wall and then a 8" stud and never touch wher they don't need to. .
Hope this helps
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Old 08-24-2016, 06:34 PM   #5
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In my little storage building cabin here in Oklahoma... All it had was 3/4" plywood floor and a few throw rugs. The walls & ceiling were well insulated and I kept warm with a quartz heater most nights, and on the coldest nights I added the milk house heater.

I think the biggest helper was circulating the air with a fan.
Most often, the Quartz Heater's thermo was set maybe 1/2 way.... BUT, this is Oklahoma and probably didn't get below 25 this last winter.

As a temporary cure, I've added 1" Foamular over my bus winders and 1/2 of my walls... Insulating a rear OSB stud wall and a forward OSB stud wall with fiberglass now
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Old 08-24-2016, 08:07 PM   #6
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with any kind of wood product used in an area of changing climate you need to leave some room around the edges for it to expand and contract... as noted in the post above..

I also believe in a bus any snap together type flooring might cause an issue as the bus flexes.. sheet flooring and stick down squares dont snap together so they can move around.. putting your foam under the existing bus floor seems quite difficult..

my bus still has its bone stock original metal floor covered by its OEM plywood then the rubber.. i get some heat from the floor but even on the hottest days my floor is never that warm... I havent had the bus in winter yet so I dont know how much cold ill have from the stock floor..

the windows are the culprit for keeping my A/C from making it an icebox... when the sun is out I feel the temperature rise a lot.. when the sun goes behind the clouds it drops.. my bus is all stock.. I drive it all over the place this way... since mine is mainly a road bus i dont worry about how much energy i use heating or cooling.. unlike what you are likely to do.. but if it were mine to make into a camper i would insulate everythign I could while building it out.

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Old 08-25-2016, 08:46 AM   #7
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Originally Posted by SmujnStar View Post
He suggested just gluing The floor onto the metal, but we want a vapor barrier....
Just a quick note: the metal floor is a vapour barrier. Adding an extra vapour barrier - such as sheets of poly - is actually making a vapour barrier sandwich, which is generally a bad idea. If condensation occurs, or water leaks down then capillary action will carry that water all over the floor and it will have no way to escape.

Rigid foam is almost a vapour barrier, but does allow moisture to migrate through, which is a good thing. In my opinion, it's the best thing to put directly over the metal floor since it will very slowly absorb and migrate moisture upwards.

I put 2" of rigid foam down before putting plywood on top and it has worked gang busters. It's especially noticeable in the winter. Insulation under the bus is a neat idea, but it will be less effective than insulation indoors since the metal floor is a big heat sink that wants to transfer heat energy to the outside walls. Still better than being uninsulated, though!

Oh, and don't worry about crushing that XPS foam. It's tough stuff. Put some plywood on top of it before the final flooring and it won't ever crush.
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Old 08-25-2016, 11:21 AM   #8
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What about noise issues? I was thinking about heat AND sound when I insulated.
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Old 11-04-2016, 10:00 AM   #9
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My Dad did spray foam insulation on the um underside of our original bus as Jolly Roger mentioned. It's been great fit the last 35 years and we're planning on doing it to the current Bus. Has anybody else done it recently though?

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Old 11-04-2016, 10:17 AM   #10
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About ready to start my interior, I have about a 2 in plywood floor that I painted with redguard, I'm planning on putting 2 1/2 in of rigid foam board then 3/4 plywood subfloor on top of that what are thoughts ??
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floor, heat loss, insulatio

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