Cellulose installation in the wood joists area and wall perimeter
I have read through several posts and articles about insulating floor joists/rim joists, including https://www.greenbuildingadvisor.com/blogs/dept/musings/how-install-cellulose-insulation, but did not find the answer.
We have a dense pack cellulose specified in the wall perimeter, in the area of 16” D open web wood joists @ 24” OC between floors.
Our insulators told us it was too difficult to install netting in that area and want to use mineral wool bats instead. Is there really no technique to install cellulose there? (both along the wood joists and when they are perpendicular, to the wall, like in the picture below). Could one wet-spray cellulose in these areas? We prefer cellulose as it has much lower carbon footprint than mineral wool.
Thanks,
Lucy
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Lucy,
It's possible to use cellulose insulation at this location, but you have to plan ahead. Here is a link to an article about a house that has cellulose insulation at the rim joists: A Superinsulated House in Rural Minnesota.
The details you are looking for can be found in Images #5, 6, and 7 in that article. Note two aspects of their approach: (1) They planned ahead by ordering floor trusses with vertical members that are perfectly located to act as nailers for the insulation fabric; and (2) each joist bay was air sealed on the interior with a rectangle of foil-faced polyiso that was carefully sealed at the edges.