Crawl space ceiling insulation – do I need to remove the old batts?
Collective wisdom,
I am getting ready to encapsulate my crawlspace and have question concerning the insulation.
It is a ’50s brick veneer ranch in climate zone 4 almost 3. It is currently a dank and dirty vented crawl with duct work in it. There is a vapor barrier on the ground(dirt) and fluffy stuff in the joist bays. My plan is to seal the vents, insulate the walls with 2″ of reclaimed poly-iso and then vapor barrier it all in (floor and walls). Also planning to cut and cobble foam to air seal the rim joist and put in a dehumidifier. My question is about what to do with the fluffy stuff. (By some feat of building science magic it is still in place and not spectacularly filthy.) I know it is standard practice to insulate the walls or the joist bays but I can’t find a good reason to pull the fluffy stuff out besides it might be a little gross. It will be far better indoor air quality than it has been. Is there any detriment (or benefit) to leaving the fluffy stuff? Would like to avoid sending it to the landfill.
Replies
forgot to mention that the batts are unfaced
I insulated our basement ceiling with R30 (unfaced) and sheathed it with 7/16 OSB. The upstair's floor became 2 *F warmer (same as the air) and it is way more comfortable. It is hard to believe that 2*F makes a difference.