exterior comfortboard ,ply,and hardie plank upgrade
Greetings
I live in Edmonton , Alberta ,Canada where our winters can get to -30 degrees for a week at a time and I
am residing and insulating my home. My home now has 50 year old rock wool that may give me R-6 if
I’m lucky. What I am thinking of doing is remove the old siding and building paper ,fasten 3 inch comfortboard
to the framing ,cover that with 5/8 plywood fastening it to the framing and then attach the hardie plank to the 5/8 ply.
Im trying to stop the thermal bridging as much as possible and if I can do it I would like to keep from strapping.
My main concern is if I use 4 1/4″ screws to fasten the 5/8 ply to the framing will that be strong enough to hold the weight of the
hardie plank? I also thought about 2 layers of 1 1/2 ” comfortboard. The first layer between horizontal straping and then verticle
straping ,the 2nd layer of comfortboard , sheating, typar, and hardie plank.
I am a ticketed carpenter so I do have the skills just need some imput to make sure I do it right the first time.
Any imput would be great!
Andy
Selkirkwoodworks