Best way to fully insulate full size bus?

[CompLexxx]

Hi, we are wondering what people think the best insulation would be in a fully stripped full size bus (floor, walls, ceiling)

We are thinking of having polyurethane (the ones made with soya base) shot the entire length of the bus as this might be the most simple, but maybe people have ideas on what could be better for whatever reasons (cost, toxic properties, installation time, etc). The bus will be used to live in full-time including in Canadian winters.

Can someone tell us how many inches of insulation are needed? We are only receiving the bus tomorrow so we have no been able to check the depths of the cavities yet. It's a 2003 Blue Bird full size.

We are open to all recommendations, thanks!

[o1marc]

Without going into the old dimentions, the walls and ceiling will accept 1-1/2" of insulation. The best is probably spray foam, but it's messy, and expensive. I used rigid board insulation in 1" and 1/2" to fill all the cavities. On the ceiling I used 3 layers of 1/2", it bends to the contour easier than 1".

[CompLexxx]

Originally Posted by o1marc

Without going into the old dimensins, the walls and ceiling will accept 1-1/2" of insulation. The best is probably spray foam, but it's messy, and expensive. I used rigid board insulation in 1" and 1/2" to fill all the cavities. On the ceiling I used 3 layers of 1/2", it bends to the contour easier than 1".

Thanks, we are thinking of having it spray foamed like they do for houses

[CompLexxx]

double post

[ewo1]

Originally Posted by CompLexxx

Thanks, we are thinking of having it spray foamed like they do for houses

For those who have spray foamed...diy or professional...

What did it cost for a full size bus?

I'm getting close on deciding how to do mine.
Foam boards are easy to place you just can't get every nook and cranny.

spray foam is messy yes, but this whole tear down and rust remediation thing...well that was messy too.

It would be interesting to see what prices are across the country.

[CompLexxx]

Originally Posted by ewo1

For those who have spray foamed...diy or professional...

What did it cost for a full size bus?

I'm getting close on deciding how to do mine.
Foam boards are easy to place you just can't get every nook and cranny.

spray foam is messy yes, but this whole tear down and rust remediation thing...well that was messy too.

It would be interesting to see what prices are across the country.

To have it sprayed it seems to cost about 2$ CAD per sq ft (for 1 1/2 inch) to have it sprayed by a professional according to my quick google searches, it might be less with checked thoroughly. I am not sure how much it would be to do it yourself.

I like the fact that it fully seals in the cabin so that condensation created in winter doesn't get to any of the metal.

[Simplicity]

I'm on, I think, my 897th version of how I'm going to insulate my bus. Here's what I've done, how I'm going to proceed (which, yes, has changed a bit from the last time I responded to a similar thread) and what I would do differently next time (next time? hmmm, really? How about finishing "this" time).

What I've done:
I used 1" rigid in the wall and ceiling cavities. It was messy to cut/break with all the little board particles. There are electric knives that will make cleaner cuts (both straight and no particles). Because my cuts were off a bit or edges were not straight, I have some gaps that I need to address.

The problem is, it only filled the cavities. The ribs were still exposed.

On the walls, I applied a 3/8" rigid foam board and then put reflectix and finally 3/8" plywood.

The reflectix will act as a thermal bridge, so don't put it directly against the bus metal.

For the ceiling, the curvature of it has been a struggle to figure out what to use.

How I'm finishing the celling:
I'm buying some loose wool insulation and using a putty knife to fill gaps between the ceiling cavities and rigid foam. Then I'm using something like this adhesive neoprene tape to cover not only the exposed ribs, but also the edges where the rigid foam meets the ribs.

https://www.amazon.com/Density-Water...a-800818163035

To secure my ceiling covering, I used a thin foam like this between the rib and 3/8" plywood strips.

https://www.amazon.com/Dow-Sill-Seal...06066819&psc=1

The neoprene tape and the wood strips will be level with each other.

Finally, I'm stapling to the wood strips Tyvek like housing wrap. This will help keep water vapor from inside the bus from getting to the insulation/neoprene tape/wood strips.

This will end up with the following layering starting at the roof and into the interior:

Henry's Tropicool
Roof sealant in joint areas
Roof
Rigid insulation
Foam strips/plywood strips & neoprene tape
Tyvek (there will be an air gap between the Tyvek and the rigid foam)
Ceiling covering

What I would do the next time:
Spray foam to the level of the ribs
1/2" Rigid foam on the walls
Thin bendable foam board on the ceiling (may need to score it a bit to make the tigher wall to ceiling bends)
Ceiling material attachment strips
Tyvek
Ceiling material

Oh, yeah, I also used regular silicone caulk over any metal fastners (screws/bolts) that have direct contact with the bus and could be a thermal bridge. Not so much for the heat/cool, but to just keep any moisture at all from finding a place to form condensation.

[musigenesis]

Originally Posted by CompLexxx

To have it sprayed it seems to cost about 2$ CAD per sq ft (for 1 1/2 inch) to have it sprayed by a professional according to my quick google searches, it might be less with checked thoroughly. I am not sure how much it would be to do it yourself.

I like the fact that it fully seals in the cabin so that condensation created in winter doesn't get to any of the metal.

The spray foam kits cost around $700 (or did, maybe they're a lot more right now like plywood) and most buses seem to require two or three of the kits, so you're looking at $1400 to $2100 to DIY (not counting the hazmat gear etc.).

[DeMac]

A few months ago, we purchaced two of Dow Froth Pak 650 kits ($700 ea.) and twenty-two 4x8x1-1/2" of OwnsCorning 250 xps ($25 ea.)

We made our purchace early because of the EPA mandated formulation change which began 1/1/21. Dupont/Dow has yet (that I know) to release the specs (R value) on the new formula, which does not use HFCs.

The attached may or may not be useful at this juncture, however, the information there-in may help explain changes to product specs, price and availability.

[musigenesis]

Originally Posted by DeMac

A few months ago, we purchaced two of Dow Froth Pak 650 kits ($700 ea.) and twenty-two 4x8x1-1/2" of OwnsCorning 250 xps ($25 ea.)

We made our purchace early because of the EPA mandated formulation change which began 1/1/21. Dupont/Dow has yet (that I know) to release the specs (R value) on the new formula, which does not use HFCs.

The attached may or may not be useful at this juncture, however, the information there-in may help explain changes to product specs, price and availability.

Ha ha you wanted to make sure you got your recommended daily intake of HFCs?

I didn't know about the formulation changes, that's interesting. FWIW the blower gases they use for XPS eventually leak out and are replaced with regular air (which has a higher thermal conductivity) and it ends up with about the same R-value as EPS. The newer stuff which does/will use higher-thermal conductivity blower gases should start out with a lower R-value than the older stuff but it will eventually end up the same anyway.

[john61ct]

Soy based??

hmm tell me more

or even better, links to trusted high-density information texts

no youtubes please

[ABBus]

Originally Posted by ewo1

For those who have spray foamed...diy or professional...

What did it cost for a full size bus?

I'm getting close on deciding how to do mine.
Foam boards are easy to place you just can't get every nook and cranny.

spray foam is messy yes, but this whole tear down and rust remediation thing...well that was messy too.

It would be interesting to see what prices are across the country.

We sprayed-foam it (closed cells). Cost was slightly over $1000. If I ever do another conversion, I'd look at another insulation system. We had some issues with the mixing of the two parts of the product (defective "gun"), and cleaning the thing to be able to redo an area is a nightmare. Anyway, we ended up with a good result (nice, almost even layer of foam), but I'm worried about water leaks. One of the benefits we saw with the closed cell is it acts as a water barrier, meaning no leaks inside the bus. But now when it's raining, I can't stop thinking of the water going between the metal and the foam, getting trapped here and damaging everything...

[DeMac]

Soy? Why not wheat or cheese.

Organic substances are the sole source of nutrition for mold, mildew, & fungus as none can feed on inorganic matter.

The aforementioned is also true of rodents and insects.

Google:
Toyota - Soy - Lawsuit
Soy Insulation - Rodents
Mold- Soy

Probably fine in dryer regions. In Florida however, I have seen mold on soy insulation. Keeping it dry is key.

[ewo1]

Originally Posted by ABBus

We sprayed-foam it (closed cells). Cost was slightly over $1000. If I ever do another conversion, I'd look at another insulation system. We had some issues with the mixing of the two parts of the product (defective "gun"), and cleaning the thing to be able to redo an area is a nightmare. Anyway, we ended up with a good result (nice, almost even layer of foam), but I'm worried about water leaks. One of the benefits we saw with the closed cell is it acts as a water barrier, meaning no leaks inside the bus. But now when it's raining, I can't stop thinking of the water going between the metal and the foam, getting trapped here and damaging everything...

So I am guessing yours was a DIY spray foam?
How many kits did you use?

Addressing water leaking, living in south Florida with our heavy rainy seasons, I already re-seam sealed the entire roof and side panels too. Hopefully that will prevent leaking.

$1,000 bucks seems reasonable to me considering it gonna be a couple hundred bucks for panel insulation and also the cost for the necessary supplies to install. Not to mention making a thousand cuts to fit everything in it's place.

How big is your bus?

Mine is a 14 window RE.

[ABBus]

Originally Posted by ewo1

So I am guessing yours was a DIY spray foam?
How many kits did you use?

Addressing water leaking, living in south Florida with our heavy rainy seasons, I already re-seam sealed the entire roof and side panels too. Hopefully that will prevent leaking.

$1,000 bucks seems reasonable to me considering it gonna be a couple hundred bucks for panel insulation and also the cost for the necessary supplies to install. Not to mention making a thousand cuts to fit everything in it's place.

How big is your bus?

Mine is a 14 window RE.

We used two kits "Foam-it-green 602". Just enough for our 40ft bus.

[CompLexxx]

Soy is expelled into soybean oil, the same kind of oil that is used to make biodiesel (in fact we plan on growing some on our farm to run our bus). It is not to be confused with the food. But yes it seems mold is an issue. There is more info here:

https://www.nachi.org/soy-based-insulation.htm

Any recommendations on the best spray foam types of busses?

[CompLexxx]

I'm leaning towards polyurethane spray foam. I have heard of it warping the walls of different camper vans it was used in, but I don't feel like this will be as much of a problem with a bus considering the walls are more rigid than Sprinters and other. (Having had a Sprinter we know the shell is pretty flexible)

[MilesOriginal]

Haven't done it, yet, but we were leaning towards Havelock wool. Look it up, it seems to have some very beneficial qualities, not to mention it doesn't contain a bunch of strange substances that may or may not be exposed as toxic at any time. Also, soy-based materials are loved by rodents.

[CompLexxx]

Originally Posted by MilesOriginal

Haven't done it, yet, but we were leaning towards Havelock wool. Look it up, it seems to have some very beneficial qualities, not to mention it doesn't contain a bunch of strange substances that may or may not be exposed as toxic at any time. Also, soy-based materials are loved by rodents.

Actually we used Havelock in our Sprinter. It's the most expensive insulation, probably costing near 3k CAD to put it. We really like it, but it wont seal and cover every single space as well as spray foam. Also spray is much simpler. If we don't spray we will definitely be ordering from Havelock again though!

[john61ct]

When it's warm in your location

identify the spray foam pro's there, that do it every day as their living

talk to the boss / owner about doing your bus at a location where they're already being paid to do a building

You do all the cleaning prep, covering / taping off the surfaces you don't want covered, then after its' FULLY cured, scraping off the excess and cleaning up.

Price will be much lower than if they do it as a standalone job.