Home & Garden

Adding insulation to outside of house and getting new windows

  • Last Updated:
  • Nov 1st, 2019 8:57 am
[OP]
Member
Aug 27, 2014
364 posts
187 upvotes

Adding insulation to outside of house and getting new windows

I'd like to get the vinyl siding of my house replaced some time over the next year or two (probably by Canexel) and I am tempted to get roxul insulation added underneath. I am in Quebec and my wife likes the house warm; we also like the idea of a greener house, although I feel like the main issue right now are the old windows and the poor insulation/air tightedness around their framing (I have seen how it was in the basement and it was just some fiberglass wool around the window and once removed, there were even tiny gaps where you could see outside). The ground floor feels slightly cold even thought the thermostat shows a comfortable temperature, as if we could feel the coldness of the walls or windows. The house was built in 1990 so I think there is probably 6 inches of fiberglass in the walls (R21?).

I would also like to get the windows replaced within the same time frame. But I am confused as to what happens if my walls become thicker. I found some video where the guy extended the windows with some aluminum I think but is that really something siding installers routinely do, I am not sure of the look it gives, and furthermore I would like to to for windows with colored frames so getting the extension the tight color could be complicated.

So I am thinking that maybe we should just replace the windows and see if that makes such a difference that adding insulation to the exterior walls seems completely superfluous? The return on the investment isn't too much of a concern. I just want the house as comfortable as possible.

I wouldn't do any of this myself so I am not even sure where to start. Get the windows installed first then see about siding plus insulation? Or get a mega headache and try to get it all done at the same time (not sure how to do that while working full time...)?
9 replies
Sr. Member
Jun 12, 2008
734 posts
175 upvotes
Ripley
Doing it all at once is the best idea. You aren't doing it so it doesn't matter if you work full time or not. Find a reliable general contractor *licensed of course*.
Deal Addict
Nov 18, 2005
4744 posts
1119 upvotes
Kitchener
6" walls would be enough insulation. Adding 1" ridgid foam board to the exterior would make it more efficient, although I dont think you'll notice much difference comfort wise. Replacing windows and doors would be significant. Cold floor could be caused by lack of insulation around rim joist and should be upgraded with spray foam
Deal Addict
Dec 17, 2007
1974 posts
958 upvotes
Alliston, ON
If your house is built in '90 I doubt it has 2x6 walls, it's likely 2x4 walls which would be R14. I'd add 1.5" of ridgid insulation to the exterior then new siding on top.
Deal Guru
Jan 27, 2006
11594 posts
4824 upvotes
Vancouver, BC
From the sounds of it, you have air leaks and adding more insulation in the walls without addressing those leaks won't do as much as you are hoping. With the replacement of your windows, I would see if the contractor can improve the airtightness (which shouldn't be a problem) specially custom fit each window opening rather than using the cheaper stock sizes and retrofitting the hole accordingly.

Next, I would look at your doors to verify that the weatherstripping is still in good condition and maybe ge a smoke pencil to check for leaks around those doors as well as the outside walls (pay attention to outlets and other joints/holes in the drywall) and address issues where you find them. Another thing you might want to check is how much insulation is in the attic as statistics show that most homeowners get the most bang for the buck in terms of insulation by ensuring that the attic has enough insulation.
Deal Fanatic
Jan 25, 2007
7075 posts
3250 upvotes
Paris
We do this type of stuff as many siding contractors also do windows (we are a window contractor who does siding, but anyways...). It’s pricey, and the last job we took on like this was 3 or 4 weeks I think.
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[OP]
Member
Aug 27, 2014
364 posts
187 upvotes
Jerico wrote:
Oct 30th, 2019 3:15 pm
We do this type of stuff as many siding contractors also do windows (we are a window contractor who does siding, but anyways...). It’s pricey, and the last job we took on like this was 3 or 4 weeks I think.
Thanks, I looked at local window contractors and the main two I had previously been considering also do siding. I'll check with them when I'm ready. Probably better on the wallet than going with a general contractor too.
Deal Fanatic
Jan 25, 2007
7075 posts
3250 upvotes
Paris
LuxErus wrote:
Oct 31st, 2019 12:43 pm
Thanks, I looked at local window contractors and the main two I had previously been considering also do siding. I'll check with them when I'm ready. Probably better on the wallet than going with a general contractor too.
Probably not actually... dedicated siding guys do siding all day long and you are paying for experience and quality. General contractors in my experience use less experienced help and can be a little cheaper, but the finished product suffers. Siding is something highly visual and you dont want someone cutting bad corners.

Any of the GC’s hourly labour guys who are any good will go into business for themselves doing siding as they can make more money. I am always suspicious of anyone willing to do windows or siding hourly.
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Deal Expert
Aug 2, 2001
16071 posts
6238 upvotes
One of the biggest things you will achieve by insulating the outside wall is fixing the heat loss from the studs. Every 16" you have a wood stud with an extremely low R Value. By having the foam (even a thing piece) you go a LONG way to getting rid of this problem. It is very, very worthwhile.

One alternative if you are worried about adding insulation is adding a radiant barrier (the foil ones). They apparently work very well - they have no R Value but instead work by reflecting the heat back. The add virtually no thickness.
Deal Addict
User avatar
Dec 10, 2008
4287 posts
755 upvotes
Toronto
The exterior foam needs to be thick enough to prevent the sheeting from getting cold.

In many parts of Canada, that means you need to hit an R10 (2" XPS)

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