Morning all, I’m new to the site and am looking to talk building science about wall systems. I’m going to try to take advantage of the home energy grant available here in Ontario Canada, by insulating my 1956 3 bedroom bungalow. Just trying to figure out the correct wall system.
Thanks
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This might be a place to visit….
https://www.greenbuildingadvisor.com/
Part of the Taunton network.
Thanks Calvin, some good information on there. I also found this article from this site (fine home building) pic attached. This is basically what I want to do, my question is do I need to create the air gap behind the siding with the furring strips of I use rockwool? Because rockwool doesn’t retain moisture would it not drain on its own within the wall cavity? Also if I do need the air gap is the primer on the backside of the siding necessary? I’ve got stucco on the exterior.
I think when you get the wall open, you will be in a position to see if water has been an issue over the past 50 years or so.
If not, I would be inclined to fill the wall cavity with rock wool bats.
You can extend the wall on the interior side by any way you like.
Last year I installed continuous 2 inch foil faced polyiso foam board on the inside of an exterior walk out basement wall, held in place with wood furring securing the foam board in place, and providing anchor for the drywall screws.
I considered glue/screw drywall directly on the foam, but decided it too challenging to hit my mark with longer drywall screws through the foam. I taped and foamed edges of the polyiso as the vapor barrier.
If you can find reasonably priced 2x4 that are straight, you might consider framing another wall inside your existing to allow for another layer of mineral wool and double the R value.
For your one section at time remodel, sealing and joining the edges of your work as it progresses will be a worthwhile focus.
I expect some of the details of your project will be influenced by availability of materials locally.
I should also add I’m in northwestern Ontario in Canada and it gets down to -35 f in the winter and up to 90 above in the summer.
I am not going to speak for Andy, but his illustration shows wood siding, which would be important to allow to dry after water gets to it from any direction.
The article has some great ideas.
How is your stucco supported? (what is the wall actually made of?)
In northwestern Ontario, my guess is you will not be cooling the house down for too long in the heat of summer and the codes for internal vapor barriers will apply to you.
How much are you willing to take apart the house to get it insulated?
Is this going to be a complete internal rehab?
Full article here for reference https://www.finehomebuilding.com/2021/04/27/managing-water-when-insulating-old-walls
https://www.ecostarinsulation.ca/blog/insulation-building-code-2021
You will need R35 to R45 walls if you need to meet current code for the program. 3 1/2 inches of rock wool is not going to be enough.
If you want to keep the existing stucco, and are willing to give up some of the interior room, you will probably have to consider a second wall frame staggered from the existing.
But this may not make immediate economic sense for you.
https://www.nrcan.gc.ca/energy-efficiency/homes/canada-greener-homes-grant/23441
You might want to start with one of the professional evaluations included in the plan and get specific bang for the buck suggestions. (how much to spend on wall insulation vs ceiling insulation vs rim joist sealing and insulation vs new doors and windows.)
Ok I’ve been told that I only have to get to R21 to meet the standard for wall insulation. So I was going to fur out my 2x4 studs with 2x2’s, install 5 1/2” R21 rockwool and then a 1” R5 extruded rigid foam to eliminate thermal bridging from the studs for a R26 total.
Are your existing studs actually 4 inches? (or 3.5 inches?)
If you are willing to make the furring thicker and run at right angles to the wall studs, you can put R15 (3.5 inches) in the wall cavities, and R10 (2.5 inches) in the horizontal spaces. You would get R25 and skip the foam. Would have to decide if you want(or will be required to have) a vapor barrier film, or want to (can rely on for local codes) painted drywall.
I believe they are 3 1/2” and yeah ok that’s another option with the horizontal framing too. Code here requires a Vapor barrier but I’ll have to find out if there’s other products that would be considered a Vapor barrier other than 6mil poly. Maybe I can use the foam as a Vapor barrier like you did.
Yeah we currently don’t have air conditioning but I will be installing central air the next time I replace my furnace probably in the next few years so I want to make sure I account for that with this Reno. I will be taking off the interior plaster and lathe completely exposing the wall cavities from the inside for about 80% of the top floor, everywhere except kitchen and bathroom for now. I’ll insulate those areas when I can get to those Reno’s as well. The stucco is I believe attached directly to the 3/4” ship lap exterior sheathing onto the 2x4 studs, from when I replaced a window about 10 years ago there is a thin tar paper between the shiplap and stucco. And yes I believe code would include an interior Vapor barrier behind the drywall. I was also thinking about putting a layer of rigid foam between the studs and drywall on the warm side to eliminate thermal bridging from the studs, anyone have any experience with installing warm side foam? And how that would work within the wall system?
Search “Mooney Wall” here in Breaktime. Interesting concept you might consider.
I'm looking to add a bit of real backup power to my house. The current setup is a 1800W generator https://wattinsider.com/best-4000-watt-generator/ that only runs the sump pump via extension cord when needed. OK for short-term outages, not too great mental health-wise for the last outage that lasted 7 hours overnight in a Wisconsin winter.