Floor Insulation

[Gonefishin]

My only insulation in the ceiling and walls is thin, factory-installed bubble wrap. Its isn't really that good. If I was more motivated, or to do over again, the best way is to remove the walls like most do on here and put in good, thick insulation. I'm sure its night and day compared to what I have.

But I do pretty well with my foam floor, factory insulation, and the Dickinson propane heater. I also put bubble wrap over the windows in the winter, as well as cover the two roof vents with a sheet or two of Reflectix insulation. I have a large blanket that is velcro'd over the back barn door that keeps draft from coming in there as well.

As for the floor, I love the texture and warmth of the foam tiles. Wouldn't have a trailer or camper without it now. Easy to clean. Soft to walk on. Holds in some heat (or keeps out some cold).

[gbowman]

I did get some of the foam pads and placed them on the floor. It has cheap and has made a difference. Floor is warmer just to walk on and it seems to have helped the overall comfort of the trailer.

[gbowman]

I have another idea I am considering. How much of a benefit would I gain for the floor insulation of I pinned up a thin sheet of metal or even plastic on the bottom of the floor. I have 6-8in’s. If I made it air tight would the dead air space added any R value to the floor? Because I don’t have a lot of time or maybe money, I was just wondering if it would be worth even messing with. Any thoughts?

[John61CT]

Anything is better than nothing.

But IMO save your pennies then do it right the first time.

The vapor barrier to stop any air infiltration (convective losses) is necessary but not sufficient.

2-4" of rigid board insulation is needed to slow down radiant/conduction losses. Spray foam to fill any gaps, ideall create a full vapor barrier effect, full foam seal across the whole envelope.

Then a dead air gap created by a plastic barrier would be icing on the cake, and your skirting just needs to block the wind.

[McDave]

https://www.homedepot.com/b/Building-Ma ... 5yc1vZcbtu
https://www.homedepot.com/p/Owens-Corni ... 585869-_-N
https://www.homedepot.com/p/GREAT-STUFF ... /206977048

Couple hundred bucks could go a long way towards warmer floors if you went this way. May not be ideal but probably R20 if it is kept dry and air/water tight. Possibly use the coroplast for skirting as well.
Just a thought.

McDave

[gbowman]

McDave,
Great idea! I had not thought about the plastic coragated cardboard. That would be light weight and rigged.
Then the fiberglass would be great and lightweight also!!
Thanks,
Garth

[John61CT]

You want rigid foam for longevity, one of the closed cell types does not absorb moisture.

Not fiberglass batts.

[McDave]

Here is another budget minded idea to consider. Radiant heat is basically electromagnetic energy or radiation, like the Sun produces. It will travel until it is absorbed or reflected. The wood floor will absorb that heat energy but it will also transmit the heat at a slower rate. if you were to line the bottom of the floor with foil you would reflect the energy back into the wood instead of allowing it to be absorbed by the insulation. This may require a gap between floor and foil or foil may become a conductor and sink heat from floor. If your insulation is 1/2" or so thinner than the cavity you are filling, you could just lay foil on top of insulation and push the batts in till flush with bottom of frame, then seal up with coroplast and foam. This may give an air gap as well between floor and insulation. The real key to making insulation work is to seal all air leaks as much as possible. Foam where frame and floor meet and where frame and coroplast meet and any seams in the plywood. There are also some wire supports that hold the batts up, they are cheap.
I can not vouch for the efficiency of any of this, or the durability but my gut tells me it could work pretty damn good if well executed.

Give it some thought.

McDave

[McDave]

John61 is correct. However, this may be an alternative. Polyiso hasn't been around forever, but cold has. I've seen a lot of crawl spaces insulated this way. I'd be willing to bet the older airstreams and like have a similar insulation. Here is an exploded view of a mobile home.



McDave

You may want to look at concrete blankets as well. Here is an example.
http://www.strongarmstore.com/shop/tarp ... gIM4_D_BwE

[John61CT]

"Foil" as in mylar, reflectix, only works as the outermost layer, facing out with dead air in front, to prevent radiant heat from entering.

Any other use is a waste.

[John61CT]

Factory mobile homes are / were hardly ever well built, never seen one what I would call well insulated.

Fiberglass is great as long as there will never be any moisture. But even Polyiso should be used in conjunction with a vapor barrier.

XPS and EPS foams have also been around a very long time, just that polyiso has better R-value per thickness.

But if XPS is a lot cheaper per inch, just use that, more thickly.

[sodatrain]

"Foil" as in mylar, reflectix, only works as the outermost layer, facing out with dead air in front, to prevent radiant heat from entering.

Any other use is a waste.

It seems that pretty much everyone puts reflextix as the first layer against the external metal skin of the rig.

You, and a few other seemingly informed sources, are saying that's a waste because there is no air gap.

Is that what you are saying? Seems to make sense it's just that nearly everyone seems to do it!!

[TheOtherSean]

The first few years of postwar Airstreams (circa 1947-1949) used 1.5" fiberglass insulation. The brochures of the time refer to it as "spun glass" but it is fiberglass. And at nearly seven decades of age, with water and insect intrusions, it can be quite nasty.

John61 is correct. However, this may be an alternative. Polyiso hasn't been around forever, but cold has. I've seen a lot of crawl spaces insulated this way. I'd be willing to bet the older airstreams and like have a similar insulation. Here is an exploded view of a mobile home.



McDave

You may want to look at concrete blankets as well. Here is an example.
http://www.strongarmstore.com/shop/tarp ... gIM4_D_BwE

[John61CT]

"Foil" as in mylar, reflectix, only works as the outermost layer, facing out with dead air in front, to prevent radiant heat from entering.

Any other use is a waste.

it's just that nearly everyone seems to do it!!

Yes, they do, but many DIYers just follow tips from fellow amateurs, info gathered from YouTubers, bloggers, maybe the guy at HD; a bit of googling, sticking to authoritative building trade insulation references, even data sheets from the materials' manufacturers will yield better information.

Using plain but robust plastic sheeting creates a much more effective and cheaper vapor barrier, since the reflective materials are usually both flimsy and more costly.

[sodatrain]

"Foil" as in mylar, reflectix, only works as the outermost layer, facing out with dead air in front, to prevent radiant heat from entering.

Any other use is a waste.

it's just that nearly everyone seems to do it!!

Yes, they do, but many DIYers just follow tips from fellow amateurs, info gathered from YouTubers, bloggers, maybe the guy at HD; a bit of googling, sticking to authoritative building trade insulation references, even data sheets from the materials' manufacturers will yield better information.

Using plain but robust plastic sheeting creates a much more effective and cheaper vapor barrier, since the reflective materials are usually both flimsy and more costly.

So you seem savvy... What's your background?

I'm deff amateur. I've done some framing, new windows etc in my home etc. There, the vapor barrier was very much the on the interior of the space (home) and the last layer before the sheetrock. It was also taped and caulked at the top and bottom plates to crate a bubble around the house. So going outside in... Sheet rock, vapor barrier , insulation, MDF of other material, tyvek or other house wrap and then siding.

Same principles should apply here right? My (many/most) CTC will have seems in the aluminum panels on the exterior. Some caulk those closed.

So.... Working inside out again would it be: stock plywood (or other surface), vapor barrier (x mil plastic, taped and caulked), whatever insulation you choose, aluminum exterior? Seams sealed?