Batt verses block insulation

One item to think about is toxicity if the worst case scenario should happen (fire). While each form of insulation releases toxic fumes when burning, spray foam has been singled out as having the highest toxicity and flammability among the three. This article sums things up nicely.

http://www.treehugger.com/green-architecture/spray-foam-fires.html

If I was redoing a rig I would use a mix of the bat and spray, only applying the spray foam away from heat sources and not in low lying areas where the fumes could come up into the cabin if a fire occurred.

I would use foam if it were mine. The heat and cold goes right around block insulation unless it is tightly fitted top to bottom, and batts lose effectiveness if it gets damp, plus the slump and clump from the bumps on the road.

if you only have a choice between batt or foam go with the foam is what i replaced the batt insulation in my t/c in sig with makes huge difference one just has to can foam any loose spots to tighten it up.. down side it does transmit more sound small price to pay for not freezing..if spray foam is doable closed cell rocks trying to get my brother to redo the insulation in underside of his cougar.. what a joke..

I agree block is better. But I could not find any manufacturers that use only block foam insulation. The closest I could find was Landmark RV manufactured by Heartland which has block in the walls and roof with a combination of block and batt in the floor. I suppose if problems arise with the floor batt insulation then at least it is more repairable than if it were also used in the walls or roof.

Kent

Foam has a higher R value for the same thickness but it's not a huge difference.

agesilaus wrote:
Yeah but in areas where you may need access, spray foam would not allow that. Like the belly area. I just replaced the batt insulation in that area with foam sheets.

For as many times as access will be needed...I will be glad to cut into my Closed Cell Spray Foam insulated underbelly!

Check out this post on another forum. The propane savings for me was very much worth it.

Hi,

If you use foam make sure it is closed cell.

When talking batt versus foam, I'm sure batt is a better sound insulator.

Yeah but in areas where you may need access, spray foam would not allow that. Like the belly area. I just replaced the batt insulation in that area with foam sheets.

Being an Insulation contractor I am not a fan of either. They all have their place sometimes but Batt and Foam block are not even close to being 70% effective most of the time.
Batt has two big issues,
1. The concept of batt type insulation is to trap air particles...which happens to be it's biggest enemy. As air moves through it, dust is along for the ride which breaks down the fiberglass strands, losing it's r-value.
2. It doesn't completely fill the space. For example in space that has wiring running through it you have two options. Cut the batt to go around it or cram it in around it. Both ways decrease r-value.
Foam block has primarily issue #2. It is never a perfect fit and always leaks air at some point.

When talking insulation, air movement is key...the least the better! If you have air movement then you have heat loss/absorption.

Spray foam is the only way to get great r-value while limiting air movement.
Have you ever watched a program on TV where they are building a HIGH end Class A? They used Spray foam to insulate it, didn't they?

The answer to your first question is yes Batt does fall down while going down the road. Get it wet and that's another story!
JMHO