Ceiling Insulation Plan

[PNWorBUST72]

So I wanted to put this down here so I can get some feedback.

I am thinking something along this lines:

1.  Glue in a true radiant barrier as the first layer, right against the outer skin on the roof, going over the metal ceiling ribs.  Then fill in the space from that to the top of the ribs with rigid foam.  I would then add furring strips along the ribs to get another 1/4-1/2 of foil lined rigid, with the foil facing in.  I might add additional furring strips to get more places to anchor the ceiling.  For now, the wife wants painted luan, I am trying  to get her to go with tongue and groove stained a light cedar type color.

Thoughts on the general concept?  What type of radiant material should I use, or the glue for it?

I am 6ft so I can loose an inch on the ceiling, if I dont go crazy on the floor.  I might be adding a MLV layer to the floor once I can confirm installation details of the product.

[TomC]

I did much simpler method. I screwed 1x2 fir strips length wise at 16" widths-mainly to have a base to screw my 1/8" plywood to the ceiling (1/8" is thin enough to bend to the contour of the ceiling). I then had the entire bus spray foamed to the level of the 1x2" strips. Gave me 2.25" of foam insulation. Yes it cost some money to have done, but it is the best and spray foaming is a nasty, messy job. Highly recommend you find a professional that has a mobile setup to come to you. Good Luck, TomC

[chessie4905]

That is the best way to do it. However, if you are on a tight budget and have the time, you can cut and fit polyurethane sheets to ceiling. Cutting smaller pieces as necessary to fill in curves,etc. Then use spray foam in cans to fill any gaps. Use a good quality breathing mask and goggles for protection from the dust you create. Good exhaust ventilation beneficial. Do this in cooler weather. A real pain in hot weather. 🔥
Having it spray foamed is really the best way to do it. You will need some more particular info from those that did or had it done if you decide to go this way.

[Jeremy]

I think the poster is mostly asking about the addition of radiant insulation rather than the use of foam - I'd be interested to hear knowledgeable opinion on this as well as I've never really been able to get my head around the merits (if there really are any) of radiant insulation

Jeremy

[buswarrior]

Shading the roof with solar panels is likely more impactful than any radiant material available to a busnut?

More cost justification to the War Department for the solar install?

Happy coaching!
Buswarrior

[sledhead]

 sm foam board with a high r value is much better then any  reflective barrier but I have used lots of this more as a vapor shield with the hope of some insulation value

https://www.homedepot.com/p/Reflectix-48-in-x-100-ft-Double-Reflective-Insulation-with-Staple-Tab-ST48100/202851852

on the M C I    I used 3/4 " plywood ripped down to 2 " wide strips  to build up ( or down ) from the ceiling at 12 " spacing side to side for more spray foam insulation and to stop the thermal transfer of condensation . 3 strips deep at the centre and out 2 ' on each side  from that to get r 28 in the middle of the ceiling and r 21 near the side walls to try to keep the height from the floor . It made it a lot easier to put up the  1/4 "plywood on the ceiling  I used the bubble foil on the floor under the laminate flooring instead of the crappy foam .   

dave   

[chessie4905]

According to the info here, you'll be lucky to get an R value of 3?

https://www.homedepot.com/p/Reflectix-48-in-x-100-ft-Double-Reflective-Insulation-with-Staple-Tab-ST48100/202851852

[PNWorBUST72]

A good professional spray foam job is probably close to $1k for a 40ft bus no?  I do love the idea though...

Unless someone can say, with personal experience that the radiant stuff works and is work the effort, then I would probably just compare pricing for the spray foam vs self installing the rigid stuff.

I like the idea of the 3/4 plywood strips, I need to plan that out.

Thanks all for the input, solar is coming. 

[richard5933]

Here's a guy that lives in a skoolie with his wife and (many) kids. He did the spray foam himself on the new bus they're converting. Doesn't look that difficult.

https://www.youtube.com/watch?v=LmtnySaDFS0

[luvrbus]

A good close cell hot spray foam will run you close to 3 grand for a 40 ft bus fwiw and that is some nasty stuff 

[chessie4905]

If you have ever used spray foam in a can, then you know how much time it takes to get consistency in thickness. It is either too little or too much since it keeps expanding for a period of time.Since it is your first conversion on an older bus, just cut and fit foam sheet and add furring strips as needed. After two of three conversion jobs, having a professional do it will seem like a better deal in time savings. BTW,Hot foam will help quiet coach too.

[TomC]

Just watched the YouTube of the do-it-yourself. One-he didn't spray it thick enough. It look like it expanded to maybe 3/4". Also he was going around the metal posts-another spot for heat/cold transfer.
My method of installing 1x2 fir strips lengthwise over the whole bus makes certain all metal is covered by either foam or minimum 3/4" wood. 2.25" spray foam is almost the thickness of what is used in a refrigerated commercial trailer.
I helped one of the ice cream manufacturers spec out their 28ft set of double trailers that was going from L.A. to Las Vegas year round. We ended up requesting 5" spray foamed walls so to keep -10 possible in 120 weather. Each 28ft trailer had the same refer unit that a 53ft'r had. I know this is extreme-just showing how much spray foam is needed. So my 2.25" is not excessive. Good Luck, TomC

[PNWorBUST72]

Besides the cost, application was the other concern with spray foam, that guy seemed like he justed wanted to finish rather then get it right.    IDK...anyone else have a youtube of spray foaming a bus?

At the TigerFoam website I think I need the fast acting $600 set.
https://tigerfoam.com/sprayfoaminsulation/order-products/spray-foam-kits/tiger-foam-fast-rise-formula-600-board-foot-kit/

I think once I figure out the furring strips and how I want to lay them out, I will work out a 3 stage "package" if I dont go DIY spray foam:

1. Maybe .5in thin foil faced- facing out
2. think rigid to fill the gap - whatever the difference is
3. .5in thin foil faced-facing in

[solardude]

Well - I'll share my DIY experience for reference. I spent well over 2K on the DIY home depot tanks to do the bus initially. I spray foamed every hole I could find, I got to the ceiling and started on that and I could not give away cash fast enough to cover the whole ceiling as I wanted. I had screwed 1x1 strips to the ribs on the ceiling to make room for wiring and insulation. After I was sick of donning on the astronaut suit and cleaning the HUGE mess, I called the mobile spray foam man. He charged about another 2K to finish the job. He said it would have almost cost the same if I had not done any previous insulating.. My advice is to save yourself the headache if you plan on spray foam... just call the professional as it is much denser and more consistent. And my opinion is the DIY stuff is a waste of time for a large space. It works great for filling in the small spaces but not for large panels. I find that the most expensive part of every project is the education. Theory is cheap (college) by comparison.

SolarDude

[chessie4905]

I appreciate you sharing your experience, painful as it may be. Some jobs are best for a professional to do. Especially knowing exactly how much to apply without excessive waste. I can see what a pita it can be just using the spray foam in cans.