Marine Zone 4 — Wall insulation — addition
Zone: Marine 4
Location: Seattle, WA
House Built: 1915
Square footage: 900 ft2 single story with 900 ft2 finished basement.
Wall height over basement: 12 ft
Current siding: Cedar, Paint in poor condition.
Insulation: not much, some fiberglass bat stuffed in nooks and crannies as they opened walls in the past. And dirty so there is plenty of air gaps.
During winter my thermostat reads 70F but still feels cold because the cold walls/ceiling suck the heat out of my body. After reading through GBA articles and forums I thought adding external insulation might be a good idea. Current plan of action:
Existing Walls: Sheet rock > 2×4 framing > some insulation, no vapor barrier > sheathing (plenty of air gaps)
New Addition: Tyvek HomeWrap > Two layers 2″ Roxul ComfortBoard 80 (old house, I fear fire) > 2×4 furring strips > fiber cement siding.
Windows: New fiberglass, inside installation.
Not adding ceiling insulation yet. That will come later after I replace electrical wiring.
Does this plan look reasonable, disastrous, wasteful?