Q&A: A Forum for Green Building Experts and Beginners

In a truss framed cathedral ceiling with R-60 cellulose and continuous vent channels from soffit to ridge, how important is the permeability of the roof membrane with a charcoal colored asphalt shingle roof?

Location; Western Massachusetts - Climate Zone 5, 7928 HDD

I’m working on the design of a two story house in Climate Zone 5 for a client with a somewhat limited budget. (I’m attaching a dwg showing the schematic section)
There are a number of different conditions in the house.
The main roof over the Second Floor will be a low slope EPDM roof pitched at ¼” per foot. The ceiling of the second floor is located at the bottom of the trusses.
There is a small portion of the house that is one story and covered by a shed roof with a metal standing seam roof that meets a higher wall.

Hi all. I know the issue of insulation for cathedral ceilings has been addressed before, but I am still confused by what the best approach is for a vented cathedral. I live in Westchester, NY. We currently have 3 large skylights in our great room. One has developed a bad leak, so we have taken down much of the ceiling and are now considering the choice of fixing them or eliminating them. The beams are 2x10s, which currenly have about 10 inches of fiberglass batts. there is no vent channel against the roof, so I assume the air just moves through the fiberglas.

Keeping with the theme of the week-- not-so foamy homes-- I am trying to come up with a solution for insulating a rim joist area with open web floor trusses that does not include foam.

Has anyone tried to wet spray cellulose onto the rim joist between/around the floor trusses? I would imagine that wet sprayed cavities need to be incapsulated on all six sides to avoid settling, but I could wrong about this.

Dense packing the area with insulweb and cellulose would a nightmare-- it would be dang near impossible to fasten the insulweb around the webbing of the floor trusses.