I'm looking to add more insulation to my exterior wall which is currently 4 inches thick. My house was built in 1967 and is located in Canada, where temperatures can drop to -30°C in winter and rise to +35°C in summer. I want to convert the wall to a 6-inch thickness and have already outlined my steps: 1) Remove drywall; 2) Take out existing insulation (it should be the pink stuff with no vapor barrier); 3) Trim the floor and ceiling drywall for adding 2x2s; 4) Adjust HVAC ducts from the basement; 5) Install 2x2s on the existing studs (debating whether to glue or use nails/screws); 6) Move electrical outlets; 7) Add new insulation; 8) Install a vapor barrier (I plan to avoid using paper-faced insulation); 9) Finish with drywall. I have a window in the wall and I'm uncertain about how to manage that. Is there anything critical I'm overlooking? I plan to test this process in a small room first before tackling larger areas.
3 Answers
Have you considered closed cell foam instead? It’s a great thermal insulator for extreme weather. If soundproofing is also a priority, combining it with mineral wool could give you both better insulation and sound dampening!
Sounds pretty solid! Just a note: when you're putting in that new vapor barrier, make sure it’s leak proof, especially with those harsh Canadian winters. Any leaks could lead to moisture buildup, which might cause issues later. Be sure to use horizontal strips at the top and bottom for your drywall support. Also, check your existing tar paper for any tears or gaps before you insert that Rockwool to ensure a tight seal! Good luck!
I think staggered studs are worth looking into; they provide a thermal break and make retrofitting easier without compromising the wall depth. Just keep in mind that butting a 2x2 onto a standard 2x4 ultimately gives you a 5-inch wall, which could compress the insulation. Also, pay attention to shear walls—they're essential for structural integrity!
And don't forget to keep an air gap between the drywall and vapor barrier for the electrical runs. It can save you headaches later!
Yeah, that's why I'm leaning towards mineral wool—as it helps with soundproofing, especially since my insulation is over 55 years old.