Rim Joist Insulation

[JeffK]

Hi All.
Illinois basement:
Want to complete the rim joist insulation properly and then drywall the ceiling and walls.
Builder sprayed 1 plus inches around the perimeter and 3/8" to 3/4" in the center of each rim joist. It seems the intent was to seal the joints and then some residual over spray in the center.
I'm having an additional 2" sprayed on the entire rim joist areas in a couple of weeks, which should bring the R-value up to R15-R19 depending on the skill of the installer.
I'm trying to avoid any additional fiberglass or rock wool added to the inner side of the foam.
I'm thinking about installing random depth gauges (screws) to aid in getting the proper depth.
Any comments or suggestions are welcome.
Thank You,
Jeff

 

[Steve123]

I'm trying to avoid any additional fiberglass or rock wool added to the inner side of the foam.
I'm thinking about installing random depth gauges (screws) to aid in getting the proper depth.
Any comments or suggestions are welcome.

In a fire, the sprayfoam would emit hazardous fumes. Therefore its code that it must be covered by a barrier that gives XX minutes of protection. Many use rockwool.

You don't need to add screws so the installers know how much they are spraying.

 

[Sparky617]

In a fire, the sprayfoam would emit hazardous fumes. Therefore its code that it must be covered by a barrier that gives XX minutes of protection. Many use rockwool.

You don't need to add screws so the installers know how much they are spraying.

Not all spray foams. Poly Iso has a fairly high combustion point. Much higher than the surrounding wood.

Poly Iso

 

[Steve123]

It's code.
You can argue with me but you can't argue with code.

 

[JeffK]

If the ceiling is drywalled then an additional barrier like insulation is not needed?
Thank you!

In a fire, the sprayfoam would emit hazardous fumes. Therefore its code that it must be covered by a barrier that gives XX minutes of protection. Many use rockwool.

You don't need to add screws so the installers know how much they are spraying.

It's code.
You can argue with me but you can't argue with code.

 

[JeffK]

If the ceiling is drywalled then an additional barrier like insulation is not needed?
Thank you!

Hi Steve
Is your message to me re: not needing wool or fiberglass if installing drywall ceiling?
Thank You!

 

[Sparky617]

It's code.
You can argue with me but you can't argue with code.

Not arguing, I've seen a lot of advertisements for conditioned crawlspaces around here where they insulate the block walls, seal the air vents and ground and add HVAC into the crawlspace. They are spray foaming the walls and leaving it exposed, best I can tell. I've also seen spray foam conditioned attics without drywall on the foam that is sprayed under the roof deck and around the rafters.

 

[Steve123]

If the ceiling is drywalled then an additional barrier like insulation is not needed?

Drywall would be a suitable barrier. Would make sense to me that ceiling drywall would make it code compliant, but I don't really know it as a fact.
I bet your sprayfoam contractor knows for sure.