What kind of spray foam insulation is best if I have a pro spray my RTS?

[Kevin Warnock]

Hi,

I have a 1994 RTS. I was going to use foam sheets to insulate, but I hear the spray foam makes the bus much quieter, and frankly, it takes time to install those sheets.

I called around today and have a guy coming Thursday to give me a quote. He says 'open cell' foam is much cheaper to buy and install. I thought 'closed cell' was the best for a bus because if you have a water leak, the foam will keep the water out. I don't have any leaks now, but the previous owner did before he caulked around the emergency exits in the roof. If that caulk wears out over the years, water could get into the ceiling and make a real mess.

The guy said the closed cell stuff dries so hard it takes much more work to grind off the excess, thus the much higher price to use it. He said he will give me two quotes on Thursday, open and closed.

I will take the bus to their shop. They have a guy who has 25 years experience who would be doing my bus, but I don't know if he has done busses before. I will be sure to ask before I agree to anything.

There appear to be lots of choices in foam besides open and closed cell. Some are fire resistant. Should I get that kind?

Basically, I need some advice on how to go forward. Anyone have any recent quotes about prices for a 40 foot bus?

Thanks,

Kevin

[brojcol]

You need to make sure you seal all your leaks first. 

Do a search on this board about spray foam insulation.  IRRC, someone came up with an ingenious little tool to remove excess insulation.  You're going to have excess.  If you get someone else to do it, get a price on removal of excess too.
[/quote]

[RTS/Daytona]

As much as you and I have had serious problems on other Bus Conversion Boards

I think you could be making a costly - mistake  - if you use spray foam

The nature of the 3/4 dimpled structure used thruout the RTS makes it IDEAL for 3/4 sheets of
foam boards - GLUED with spray contact cement

Mines 4 years - no leaks / no squeeks / no rattle / just super

Here's a post I wrote a long time ago


Hi

The small dimples in our (RTS) ceiling are 3/4" - I cut 3/4" foam sheets
and used contact cement (solvent based- no wimpy water based crap) to
fill the inside of all the small dimples

That leaves another 3/4" of space between the foamed dimples and the
Cross members seams - I added more 3/4 by 1' wide  contact cemented foam sheet
strips to bring the ceiling level with the edges of the crossmember 5'
seams

so far that's 1.5" of insulation in a majority of the ceiling just to
make the ceiling level with the 6'8" (measured in the center)
crossmember seams

I contact cemented an addition 2" worth of foam strips (1' wide so
they would bend and would be easy to handle) - i did it in layers
3/4" and 3/4" and finished with 1/2" foam strips

left 10" wide channels on either side of the escape hatches (front to
back) for my "DUCTED A/C" and used 1/8" RV Duct/Boards to form the
duct work

that's about 3.5" of insulation in the ceiling -

I used the same idea for the walls (Dimples first - then depression
between the members then added 3/4" before the indoor/outdoor
carpeted walls

My windows are factory tinted - I have only 2 windows on each side
blocked (I have a 35' RTS)

I am AMAZED how long my RTS HOLDS TEMP - If it's been a cold weekend
and I go to the bus on Monday AFTERNOON when it's now hot outside -
The bus is cold - same if it seats without a/c running and gets hot
inside and it's a cold cold night - the heat last a long time


It's like riding in a THERMOS BOTTLE - it holds temp well -

It should be noted that I have silver colored aluminum micro mine
(1/2") binds on all the windows and they are almost always closed

Your result may vary ??


THIS IS WHAT I USED
http://www.rmaxinc.com/Rmatt-3%2005-07.pdf

additional info
http://www.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11590

Pete RTS/Daytona

[JohnEd]

RTS,

I understand that you have 3.5 inches on the overhead.  What does that break to in terms of R VALUE?  What did thwe foam board cost you to do the bus...better yet...how many 4X8 sheets did you use?

Thanks

John

[RTS/Daytona]

3.5 " of R-MAX is rated at 23.2 R  thats 4 times 5R for the 3/4"  + 3.2R for the 1/2"

My guess is (I didn't count) about 30 4 x 8 sheets of R-max mostly 3/4 and a few 1/2"

It was a lot cheaper before KATRINA - don't know what it is now

My side walls are 3/4" in the dimples - 3/4" to go flush with the ribs - 3/4" between the furing strips for an R15 rating

PLUS this stuff is reflective - I believe there is a substantial gain by reflecting heat with multiple reflective layers ??

Pete RTS/Daytona

[RJ]

Kevin -

Another source for spray foam would be through the commercial body shops that specialize in repairing reefer trailers for 18-wheelers.  If there's one in your neck of the woods, ask their shop foreman.  If they don't actually do it, he'll know who does.

FWIW & HTH. . .

[TomC]

I had two guys come in a spray the hot foam.  It is a two part liquid- looks like engine oil when coming out then changes quickly to off white and expands-pretty bazaar.  It is REALLY stinky stuff when spraying-so much so that the two sprayers had helmets on with hoses attached to Kirby upright vacuums outside the warehouse pushing in fresh air into their helmets. 
I had screwed 1x2 fir strips going lengthwise about 12" apart.  This did two things- one made the insulation thicker (2.25") and also covered all exterior metal, and two made something to screw the plywood inside wall two.  They started at 9pm (worked at night when it is cooler), and by 7 am had the whole bus done, ground flush with the 1x2's and had the whole bus cleaned up.  Well worth the $1,650.00 I paid for in 1994.  That's one job I definitely did not want to do and will never do.  Really pretty nasty.  After about a week, the smell goes away.  It is a closed foam, which I suggest to you.  You don't want open foam in case of a water leak-it will create mold like crazy.  Highly recommend the spray foam.  Good Luck, TomC