Sloped ceiling insulation
I have a story and a half home that we are remodeling. We also added a garage with bonus rooms above. We are climate zone 6 in Gillette WY. We taped all OSB seams, are adding 2” of rockboard insulation with 3/4 rain screen and Lp smartside lap siding to the exterior and used ThermalBuck to fur out our windows. We will also be using Ecoseal Plus to air seal interior framing.
To the point:
I have read extensively about how to insulate sloped ceiling spaces(http://www.finehomebuilding.com/2012/09/06/two-ways-to-insulate-attic-kneewalls). We will have an unvented roof assembly. I understand the two methods of insulating attics with knee walls. Keep the attic cold or bring it indoors. Here is my question. Can I keep the attic outdoors by insulating the knee wall and floor below with dense pack and then foam the sloped portion of the ceiling inside of the knee wall until I reach the flat ceiling at which point I would go with a blow in? In this case the first and third segments of the roof would have no insulation in the rafter bay with only insulation touching the roof in the middle third of the rafter bay. I’m trying to minimize the amount of spray foam needed to have a well insulated room and a healthy roof.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part