Double-Studs and Roxul
I am working with a builder to finalize design of a house on the great lakes in Canada (zone 6).
Our wall plan is 2 x 2x4 with 3 layers of roxul batts vertically in the stud bays and horizontally in between the stud bays and interior poly vapour barrier. The builder has a good reputation for energy efficient houses and reports no problems in walls he has investigated after many years in place.
From reading about monitoring moisture levels in double stud walls ( http://www.greenbuildingadvisor.com/blogs/dept/musings/monitoring-moistu...)
It seems as though this type has some risk associated with elevated moisture, particularly north walls.
My thought was to sheath the north wall with plywood, other walls with osb and use a ventilated rain screen behind unfinished white cedar siding all the way around. I am wondering if this is enough or whether we need to do plywood all the way around or put roxul boards on the outside to keep the sheathing warmer, or use a different wall system altogether with exterior foam or roxul board sheathing.
We will have Georgian bay to the south and east on our lot, so it is a little moist and moderated climate
Heating is in-floor with woodstove and an HRV will be installed.
We also have a mudroom with laundry located outside of this enclosure and a sunroom - thought being to keep the dryer vent separate and to have a sunspace that can be closed off from the house. Are there any durability issues with insulation choices in these locations - sunroom in particularly being warmer.
Posted Tue, 06/24/2014 - 06:29
Other Questions in Energy efficiency and durability
Since drywall has a permeance of 0.02 liter/sec - m at 75 PA is ever possible to have sheathing dry to the interior of the home?