Wall Assemblies
"For these locations, I follow the widely quoted recommendations from Building Science Corporation and aim for the 5-10-20-40-60 rule. These numbers refer to the R-value recommendations for windows, foundation slabs, foundation walls, above-ground walls, and attics (or roofs), respectively." http://www2.buildinggreen.com/blogs/how-much-insulation-enough "Refining Bob's double studwall suggestion a bit, rather than two 2x4 walls, make the non-structural wall finger-jointed 2x3s 24" o.c.. With finger jointed studs you'll get better wall flatness even with the wider spacing, use less wood, and achieve a measurably higher R thermal break at the same wall thickness." http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/31260/would-2x8-studs-filled-dense-packed-cellulose "Whenever you install rigid foam on the exterior side of your wall sheathing, you need to make sure that the ratio of exterior rigid foam to fluffy between-the-studs insulation is correct. If the rigid foam is too thin, you can get moisture accumulation in your sheathing during the winter. This is all explained in this article: Calculating the Minimum Thickness of Rigid Foam Sheathing....
Manufactured at Roxul’s Milton, Ontario, factory, ComfortBoard IS is third-party-certified to have a minimum recycled content of 75%, and the product can be specified with recycled content up to 93%. ComfortBoard IS, the residential product, has a density of 8 pounds per cubic foot (pcf) and is available in four thicknesses: 1 1/4 inch, 1 1/2 inch, 2 inches, and 3 inches The insulating value of ComfortBoard IS is a very respectable R-4.0 per inch. That’s lower than XPS (R-5 per inch) and polyiso (about R-6.0 per inch), but there will be no “R-value drift” (reduction in R-value over time), which occurs with foam insulation materials that rely on lower-conductivity blowing agents that slowly leak out or allow air to leak in. A very attractive property of ComfortBoard IS is the high permeability to water vapor. A 2-inch layer of the insulation has a permeability of about 30 perms, which means it’s highly breathable. If the ComfortBoard is installed on the outside of the wall, the high permeance will allow excellent drying potential to the exterior Although Roxul literature shows ComfortBoard IS being available in three sizes — 24" x 48", 36" x 48", and 48" x 96" — it is most common...
sealing exterior wall electrical boxes
Q