# Framing Insulating Basement - Ontario Canada



## Ironmanx (Sep 7, 2015)

So I finished part of the basement back in 2009. Need to get the rest done.

I'm guessing there is roughly 50' of unfinished wall that needs to be finished.

So back in 2009 the code was for R12. Went to a couple of hardware stores ended up buying 2" C-200 Extruded Polystyrene Rigid Insulation. It actually had strapping that could be installed so you could attache dry wall to it. Thinking back I don't get it code was R12 2" board it R10, I guess they are factoring in the foundation wall will at least be R1.5ish and the drywall R0.5. I did not attache the drywall right to the board I built a 2x4 wall with no insulation between studs.

I've had no issues.

So the code changed in 2012 I believe to R20.

I figure well I guess I can do what i did before and through batt insulation between the 2x4 studs.

I look up 2" C-200 Extruded Polystyrene Rigid Insulation and it doesn't seem common anymore in my area. You can see tons of 0.5" and 1".

I'm thinking the 2" just doesn't make financial sense with the new R20 rule.
So what would be the most cost effective way of framing an R20? 
I still want to use Rigid Insulation.

0.5" rigid (R2.5) then 2x6 (Roxul 22) = R24.5
1" rigid (R5) the 2x4 (Roxul 14 = R19 (i need 20 but the whole buying R10 when it was R12 code has me thinking i'm only 1 off and this looks like its probably the most popular in my area by what is supplied at the store. Why else is 1" rigid kept in stock so much).


0.5" 2' wide rigid looks to be $8 
1" 2' wide rigid looks to be $16

2x4x8 = $3.30
2x6x8 = $4.48

1/2" 4x8 drywall = $7.79

R22 For 2x6 Studs 24 In. On = $43.89 (Covers: 37.5ft2)
R14 For 2x4 Studs 24 In. On = $45.60 (Covers: 60.1ft2) 

R22 For 2x6 Studs 16 In. On = $46.59 (Covers:39.8ft2)
R14 For 2x4 Studs 16 In. On = $$45.59 (Covers: 59.7ft2)




Any reason to go for 16" over 24" on centre? 
It is just basically holding up drywall.

Only pro is going from 41 studs (16" On Centre) to 28 studs (24" On Centre)
Saving 13 studs $42.90-$58.24. Mehhh not a huge deal price wise. 

-------------------------------------
So i think R19 not including the foundation and drywall would probably be ok code wise since R10 was when the code was R10 (I'll ask the hardware store too).

R19 would cost me:
2x4 (41x3.30) = 135.30
1" R5 rigid (26X16) = $416
50Wx8H = 400SQFT (400/60.1) = 7 bags (7X$45.60) = $320
Drywall 12 4X8 x $7.79 = $93.48
Total = $964.78

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R24.5 would cost me:
2x6 (41x$4.48) = $183.68
0.5 Rigid (26x8) = $208
50Wx8H = 400SQFT (400/39.8) = 11 bags (11X$46.59) = 512.49
Drywall 12 4X8 x $7.79 = $93.48
Total = $997.65


Wow closer then I thought. I guess for the $30ish more its worth it to go with the R24.5. Con is it would cost me 1.5" in wall thickness.

Good talk guys.... Haha its helps just to talk this out.


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## Ironmanx (Sep 7, 2015)

Any issues going from the 2" rigid to the 0.5" rigid???
I assume as long as I tape it well like I did the seams I should be alright.
The 2" stuff was ship lap and i would want that again for the 0.5" stuff but where it meets will be like a butt joint.


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## Ironmanx (Sep 7, 2015)

To make it clear there will only be 2 places where i will be going from 2" to 0.5" rigid foam. 
From R10 wall to a R24.2 wall. (I've actually heard an uninstalled 2x4 wall has an R rating of 4 something).


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## Bud9051 (Nov 11, 2015)

There is a ratio of fiber insulation to rigid that maintains an above dew point on the inside surface of the rigid. Too little rigid or too much Roxul on the inside and the rigid becomes too cold. Now, the only guidance I have for that is not related to basement walls so you need to use your judgement. The above grade foundation would be the closest to an exterior stud wall assembly.
http://www.greenbuildingadvisor.com...rmal-mass&utm_campaign=green-building-advisor

Bud


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## Ironmanx (Sep 7, 2015)

Bud9051 said:


> There is a ratio of fiber insulation to rigid that maintains an above dew point on the inside surface of the rigid. Too little rigid or too much Roxul on the inside and the rigid becomes too cold. Now, the only guidance I have for that is not related to basement walls so you need to use your judgement. The above grade foundation would be the closest to an exterior stud wall assembly.
> http://www.greenbuildingadvisor.com...rmal-mass&utm_campaign=green-building-advisor
> 
> Bud



Thanks Bud I will look into that.

I assumed since this stuff is made for basement interior walls it must be alright. 

"FOAMULAR® Extruded Polystyrene Rigid Insulation is made in Canada and offers a combination of characteristics that result in long-term thermal performance of R-5 per inch, compressive strengths of 20  100 PSI and exceptional moisture resistance. Using FOAMULAR® insulation can create comfortable living spaces in basements, as well as minimizing heat loss or gain when using it on above-grade exterior walls and the interior of foundation walls. FOAMULAR® Extruded Polystyrene Rigid Insulation is lightweight and durable making it easy to handle, saw, cut and score.
"

I'm thinking since 1/2" and 1" are what is in stock and this stuff is primarily used for interior basements walls ( i think primarily) it must be the way people are doing it.

I will have to ask the store what most people do also.


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## Ironmanx (Sep 7, 2015)

Weird I don't see the 1/2 on the manufactures website.

http://insulation.owenscorning.ca/architects/products/c-200.aspx



https://www.homedepot.ca/en/home/p....x-96-inch-x-12-inch-butt-edge.1000436411.html


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## 123pugsy (Oct 6, 2012)

2 x 1" styrofoam if no 2" sheets available, 3.5" Roxul, VB, drywall.

Building inspector said he wouldn't accept the styrofoam as a VB. I didn't want a VB in the basement so I spray foamed. Well, not DIY but had a company do it for me.


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## Ironmanx (Sep 7, 2015)

123pugsy said:


> 2 x 1" styrofoam if no 2" sheets available, 3.5" Roxul, VB, drywall.
> 
> Building inspector said he wouldn't accept the styrofoam as a VB. I didn't want a VB in the basement so I spray foamed. Well, not DIY but had a company do it for me.


Its a good thing you went with the spray. The vapour barrier behind the drywall is a double vapour barrier. Unless there are some types of rigid foam that dont act like a vapour barrier but that is kinda there main advantage they work better then the sheet plastic.

The best way to insulate a basement is with the rigid board on the outside of the wall.


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## Ironmanx (Sep 7, 2015)

Oh i have seen where you put up the framing and put the rigid boards in between. That defently would not be a vapour barrier. I think even the home depot .ca has a video of this.

The way it acts like a vapour barrier is when you glue it to the wall tuck tape all the seems between the boards and then build your wall up against that.

2" rigid insulation with 2x4 framing makes a 6" thick wall.


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