Sidewall insulation

[Ncbob]

We're starting on re-converting the bedroom of our MC5A this week.  I'm armed with a shopping list of materials that should make the local plywood supplier more than happy.  Fortunately we have a guy who deals in premium grade woods and the cabinet maker has decided to use Okami (sp?) plywoods for all the cabinets and beds.


We're looking for a recommendation as to insulation along the sides of the room...against what's already there.  I've ruled out blueboard because of it's toxic nature and am asking for some suggestions.  We plan on retaining the original rear bus windows (escape) and will work around them.

Any suggestions..closed cell...open cell.. and (please) why.

Thanks,

Bob

[JackConrad]

Bob,
   I think you will find that all foam type insiulations give off toxic gases when exposed to flames. A far as closed cell vs. open cell,  closed cell has better insulating qualities and more importantly will not absord water near as readily as open cell foam. A sponge is an example of open cell, a diving wet suit is an example of closed cell. I have helped a friend who was re-doing an Eagle insulate his sidewalls. we used a double layer of 3/4" polyisocyanate foam (this is the amder colored close cell rigid 4X8 sheets with aluminum foil and/or a thin vinyl layer on each side) frequently sold as R-Max or Thermax. We cut these slightly undersize, glued them in place, then filled the gps with cans of sprayfoam. If I remember correctly, this gives an R factor of about R-7 per inch. The R factor should be printed on the sheets of insulation.  Hope this helps, Jack

[Beatenbo]

Bob, You looked at that stuff MAK adevertises for, Concourse West that 1/4in stuff I have a sample of should be graet. It's a little pricey but suposed to be good. Of course if you own a bus money is no object!

[pvcces]

I was interested in getting some foam insulation, too, but became concerned about the toxicity of the foams. It appeared that the polystyrene was a lot safer than the other foams, and would be the foam I use, if I use any.

For what it's worth.

Tom Caffrey
Suncatcher
Ketchikan, Alaska

[Danny]

I just finished my walls about a month ago.  I used a combination of rigid foam boards to get the thickness needed with spray foam for the gaps.  Worked pretty well...  Toxic?  The fire in the coach would be more toxic than the foam board in the case of fire ... :-)

Danny

[Kristinsgrandpa]

I'm using polyisocyanurate (R-Tuff) it has the highest R value.

By the time the fire burns through the plywood I'll either be dead or out of the coach.

Ed

[NJT5047]

I used Foamular from HD.  Used it in ceiling and skinned windows (2-- 3/4" layers for 1.5") and furred out for 3/4" on all the interior walls which gave 2.25" behind all the skinned windows total.  Figured I could give up another 1.5" for the comfort and sound control.  Worried about squeaking, but the foam is bonded with Great Stuff and adhesive which seems to have worked well...no squeaks.  FWIW, some foam boards are not compatible with adhesives such as Liquid Nails. 
Because I'm a cheapskate, I put all the aluminum ceiling panels back up once insulated...worked out fine, but made installing a headliner more complex...so complex it ain't happened yet.  It will.
As Kristinsgrandpa and Jack sez, by the time the foam is burning, the toxic fumes will be the least of my worries.  I'll be out of the bus...or a crispy critter. 
The more insulation the better! No doubt about that.  Worth the effort and expense.
Now the only area that has heat load or loss is under the dash.  That doesn't have much effect on the comfort of the bus.  Have heavy curtains on tracks that pull over the windshields that are a wonderful thing when camping in really hot weather and the bus is facing the South.
BTW, Foamular advertised an insulating factor of R-8 per inch...been some discussion on exactly what conditions the R-8 would perform?
Cheers, JR