Insulating under the bus?

[Great_wide_somewhere]

I was thinking of using wool to insulate my bus. Would it be feasible to insulate UNDER the bus, and protect and cover it with a rhino liner or something? I can't afford a roof raise, and am trying to save height inside the buss

[Jaybz]

It’s technically possible, but extremely hard to do well. Trying to insulate the underside properly will likely be harder than a roof raise.

[ewo1]

Originally Posted by Great_wide_somewhere

I was thinking of using wool to insulate my bus. Would it be feasible to insulate UNDER the bus, and protect and cover it with a rhino liner or something? I can't afford a roof raise, and am trying to save height inside the buss

I got an travel trailer for parts that was damaged in a hurricane, the entire underside is covered in a "plastic type" of covering.

I can imagine that it is to protect the underside components from the elements but does it also help at all in insulating or creating a vapor barrier on the underside that would help keep the road heat from heating the floor in the summertime?

[Biscuitsjam]

There are lots of components under the bus. Insulating around them all is near-impossible. Also, metal conducts heat pretty well, so whatever is not insulated will mostly negate the work you did if you aren't thorough.

[Rucker]

If you can't do the floor b/c of height, might need to consider oversizing your heater and going with slippers and a throw rug...

Is a cold floor a problem for folks in the colder climates? How much discomfort comes from no insulation in the floor (versus little/no insulation in the walls and ceiling)?

[musigenesis]

Go out and crawl around under your bus and just try touching with your finger every spot on the underside of your floor (knee pads would be a good idea for this, and probably a helmet). I think people that contemplate this have never considered what the actual physical experience of doing it would be like. That's why this gets suggested a lot but almost never actually even tried.

And the standard idea involves spray foam, which is at least self-adherent (if the surface is cleaned and prepped, which is no fun underneath a bus) and waterproof. Wool is neither of these things - maybe not that appropriate for the underside of a vehicle.

[Rucker]

Originally Posted by musigenesis

Go out and crawl around under your bus and just try touching with your finger every spot on the underside of your floor (knee pads would be a good idea for this, and probably a helmet). I think people that contemplate this have never considered what the actual physical experience of doing it would be like. That's why this gets suggested a lot but almost never actually even tried.

And the standard idea involves spray foam, which is at least self-adherent (if the surface is cleaned and prepped, which is no fun underneath a bus) and waterproof. Wool is neither of these things - maybe not that appropriate for the underside of a vehicle.

Also goggles, for the years of road crud that will drop on your face.

[rossvtaylor]

This stuff works well and is designed specifically for that. We've used it twice and liked the results. We did talk to them about setting up a commercial account, but we're not doing enough regular volume for that. Our spray foam window is seasonal, so during the winter we wouldn't be buying any. We do like the product, though.

https://www.handifoam.com/product/ha...l-vehicle-hfo/

[Ronnie]

I have spray foamed under railroad cars. It works, and it is a mess to do.



On our bus we do not have insulation on the floor. Just plywood and carpet. Think the carpet makes a difference. Generally we are not in temps lower then 20 degrees or so, and as long as the bus is warm the floor is warm enough for bare feet.


If you are parked for a bit somewhere in cold weather any barrier to keep wind for going under the bus will do a lot for floor temps.

[flattracker]

If you want to insulate your floor without a roof raise and not give inside height look at this type of insulation that I got. It has an R value exceeding 15.


US Energy 5mm reflective foam core insulation.



It is about .2 inches thick. It is spendy to buy, but simple to use. I got mine on eBay, but can be sourced on the net

[BeNimble]

Just buy another vehicle that does not need its roof raised and its leaky windows replaced,
like a box truck if you like doing things the hard way (which you must, you bought a school bus).

Otherwise, they use wood stoves in big buses to compensate for losing 70% of the heat, air conditioning not so lucky options for off-grid, so better drive the bus to Hawaii.

[Simplicity]

RVs and Travel Trailers are rated for 3 season or 4. The main difference is that the undercarriage is insulated and then a non-rip waterproof fabric is put over the insulation. So yes, it's done.

But, they are designed for this and it's done during manufacturing.

A bus has so much "stuff" running under it, it would be an herculean effort.

My suggestion for the floor is a 1/2" rigid foam insulation covered by a minimum of 1/2", preferably 3/4" plywood that is evenly bolted through the floor of the bus. My bus had 3/4" plywood and 1/8" rubber in it originally. That's 7/8". So, if you're only adding 1 - 1 1/4" from bare metal floor, you really are only adding a net 1/8" - 3/8".

For the ceiling, I'd suggest spray foam (if you have the money, and if you've got more money, include the side walls). This is how I would do it if I ever convert again. The alternative is thick wool in the spaces between the roof ribs and a 1/4" x 4' x 8' sheets of insulation with the shiny side facing inwards to reflect back the heat. Then, a 1/8" x 4' x 8' ceiling material. This is a total of 3/8". If you measure the thickness of the original sheet metal ceiling that you removed, that shaves another 3/32" off...for a total of 9/32".

Between the floor and ceiling, that's a maximum additional 21/32" (~5/8"). That's not much considering all the floor and ceiling insulation you'll have.

Believe me, the first time you're laying in bed freezing, you'll wish you had better insulation!

Best of Luck.

[Rock-N-Ruth]

Originally Posted by Great_wide_somewhere

I was thinking of using wool to insulate my bus. Would it be feasible to insulate UNDER the bus, and protect and cover it with a rhino liner or something? I can't afford a roof raise, and am trying to save height inside the buss

It depends on the bus body and where the engine is. If you have a front engine bus then you have exhaust system and driveshaft to deal with. If you have a rear engine bus insulating the underside with 2 inch XPS is pretty easy.
We have insulated some of the underside of the bus. And when we get to building are under coach storage we will insulate the rest. We also saved a lot of inside Space by insulating on the outside of the bus and then covering it with quarter-inch plywood. We call it the hillbilly way. Some might just call it cheap and effective.

[TJones]

I think I will be reinsulating under my bus. It has spray foam on the bottom from the factory but it seems to be getting loose in places. The foam is stuck to the underbody coating but the coating is coming off the metal. I think that pressure from the expansion of the foam between the floor ribs is what is holding the foam on. The good news is the metal looks brand new under the foam. My plan... unless I talk my self out of it is to pull the factory foam off, paint any rust I find and then spray new foam. I had origionaly wanted to add more foam to the full depth of the floor ribs to the existing but I don't want to go over foam that isn't stuck down. I'll post some pics when I get started with that "fun".

Ted

[rossvtaylor]

TJones...when you do that, try the product I mentioned above. It works really well.

[TJones]

Originally Posted by rossvtaylor

TJones...when you do that, try the product I mentioned above. It works really well.

Thanks. I will check it out.

Ted

[flattracker]

I think this is the thread where i jumped in with my two cents about insulation. Someone thought that I might have been deceived about the US Energy Products insulation. I looked into it again tonight and made note of a place on the net where claims about the insulation were made. I found this:
https://www.amazon.com/US-Energy-Pro.../dp/B07YYNL4LW


The statement found there:


"EXTREMELY EFFECTIVE - Reflect 97% of radiant energy, perfect RADIANT BARRIER. R-value up to 15.62 (1 layer), up to 21.10 (2 layers) (building envelope)"


when doing a google search of "US Energy 5MM Reflective Foam Core Insulation r value"
found "Prevents 97% of radiant heat transfer"
also states "
R-Value = 8 unaffected by humidity" but I think that is for the thinner version. It appears that its rating comes from reduction of radiant energy.
It is a product of USA. I invite comments because If I am wrong let me know.
Thanks

[musigenesis]

Originally Posted by flattracker

I think this is the thread where i jumped in with my two cents about insulation. Someone thought that I might have been deceived about the US Energy Products insulation. I looked into it again tonight and made note of a place on the net where claims about the insulation were made. I found this:
https://www.amazon.com/US-Energy-Pro.../dp/B07YYNL4LW


The statement found there:


"EXTREMELY EFFECTIVE - Reflect 97% of radiant energy, perfect RADIANT BARRIER. R-value up to 15.62 (1 layer), up to 21.10 (2 layers) (building envelope)"


when doing a google search of "US Energy 5MM Reflective Foam Core Insulation r value"
found "Prevents 97% of radiant heat transfer"
also states "
R-Value = 8 unaffected by humidity" but I think that is for the thinner version. It appears that its rating comes from reduction of radiant energy.
It is a product of USA. I invite comments because If I am wrong let me know.
Thanks

The thing about a claim like "prevents 97% of radiant heat transfer" is that at the temperatures humans exist at (0°F to 100°F, say) radiant heat transfer makes up a tiny, tiny fraction of the total heat transfer, being dwarfed by the heat transfer due to conduction and convection. The reflective foil on insulation only becomes useful in the special case of a building (or vehicle) out in direct sunlight and heated up well above the ambient air temperature; and it only works at all if the reflective layer is facing the heated roof and has an air gap of at least 1" adjacent to it (which nobody ever does in a skoolie); and in this scenario it only provides a benefit of R-2.

The claim of R-15 (the equivalent of 3" of XPS foam board) from even a correctly-installed radiant barrier is really not at all plausible.