First and foremost,
Thanks to all those who contribute, I’ve learned a lot over the past while reading others’ opinions and posts.
I am in the early stages of planning an exterior renovation to improve the efficiency of our house and we’ll be doing a lot of the work ourselves as I am a carpenter.
We live in Edmonton, Alberta in a two-story built in 2000 with 2×6 walls an interior 6 mil vapor barrier, and fiberglass batt in the cavity.
The exterior sheeting is OSB with two layers of black felt which is not taped covered with vinyl siding.
We recently had an energy assessment completed with a 5.5 Ach at 50 pascals
Our advisor recommended new windows “triple pane”, as ours are original dual pane without Low-E, which have a U-factor ranging from 0.51-0.52 or r2, not the best insulating value granted but are in good condition which is why I am apprehensive about replacing them given their condition.
We priced out new windows on average we’re getting quotes between 17k-24k just for supplied only
Which is 2/3 of my budget.
The more research I do the more it appears I should focus on air sealing.
I wanted to know if would I be better off leaving my existing windows and installing removable storm windows on the inside with tinted plexiglass which will likely cost about $1500 materials only”.
I am thinking of focusing my attention on the exterior by completely removing the siding, felt paper and starting from scratch while leaving the windows for the time being.
Tape OSB sheeting with 3m tape, seal the sill plate with a fluid applied that is compatible with Tyvek, and wet-set Tyvek commercial D, tape the joints covered with 2 layers of 2 1/4 inch Eps with offset joints taping the outer seams giving me an r20 with a 1/2 rain-screen with vinyl siding.
Tape the OSB with 3m tape, seal the sill plate with fluid applied likely fast flash, wet-set Siga Majvest 200, tape the seams covered with 2 layers of 1.5 inches of rock wool giving me about an r12 with a 3/4 rain screen with vinyl siding
A few considerations with option 1
My initial thoughts would be to avoid installing 4″ of exterior foam as I have an interior vapor barrier which would limit drying potential to the interior but then I read “mind the gap” posted here.
It had a reference about being able to safely install exterior foam on top of a drainable WRB so long as there’s a gap between the two hence Tyvek commercial D “wrinkled WRB” to allow drainage even though I have an interior vapor barrier.
Just wanted to seek people’s input on such a wall assembly, it is a more economical solution roughly 35+/-%, easier to install with a better r value.
After reading “calculating the minimum thickness of rigid foam sheeting”,
According to the article my climate zone 7 a would require R15 exterior insulation to keep my walls warm enough to avoid condensation,
Does this apply if you are installing exterior Rockwool insulation or would 3″ R12-R13 suffice?
Your input is appreciated.
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