sealed crawl walls

[Sifu]

I have an DP specifying rock wool draped down the interior face of a crawl wall to provide the required r-value. They will have it sealed behind the poly to provide the encapsulation of the crawlspace environment. I typically see a closed cell insulation and have never seen loose batts draped this way. I am concerned about moisture wicking and being held behind the poly although if the interior is sealed maybe that is not a problem. I don't know. Anybody seen this before or have a yes or no code reference?

 

[Gregg Harris]

It is listed for the application and can be provided with vapor barrier attached.

According to NAIMA rock wool glass fiber and plastic foams absorb less than 1% of their weight. Cellulose will absorb 5-20 %

 

[PITBOB]

The drape insulation that I see is 4' wide fiberglass on a roll, the vinyl vapor barrier has small perforations so it can dry. It's attached to the sill plate and a sleeper near grade