Walls and Ceilings - Need help.. Framing exterior wall on the inside..

Before I start demolishing, i want to make sure i have the right idea on how to proceed after.

The inside of my exterior wall is made of strapping, lathe and plaster. I am planning on breaking it down to the bare wall.

This is what i plan on doing after, would it work?

1. Screw 2x2 or 2x3 on its flat side to the wall giving me 1 1/2" thickness. I would space this out 24 inches apart.

2. I would then in between the 2x2 place pink rigid insulation sheets ( 2'x8')

3. Then place drywall.


Now for the drywall screwing, 24" apart is I assume insufficient, but i seen pink rigid insulation that has grooves to place metal furing channels that you screw with concrete screws on top of the insulation, can I do that? and then screw drywall to those?


I understand I should be looking at 2x4 walls but my space is limited, going with 2x2 will give me pretty much the thickness that I already have with added insulation.


Last but not least, my question is about vapor barriers? Do i need to place a paper on the barewall first like a typar paper? And do I need to install a 6mil vapor barier on top of the insulation..

Thanks for any help provided.

The other way I was thinking of doing it was this--> With rigid foam insulation (http://www.owenscorning.com/worldwide/canada/HowTo.asp?HowToID=9&Language=1)

It says it is basement walls but can't I do that on my first and second floor exterior walls? Would same me so much time...

Sounds like your bare wall is block or concrete??
Above grade takes one solution, below grade another.
2" of foam is kind of thin for Toronto.
24" on center is OK for sheetrock. Instead of strapping as stated, use one or two inch glued to smooth concrete wall. Over that apply 1.5 inch with notches as you describe for straps. Total 2.5 or 3.5 foam and apply sheetrock flush to foam. No vapor barrier next to outside wall, but a layer of plastic just before the sheetrock.

Any electrical on that wall will need special detailing.

Bud

Sounds like your bare wall is block or concrete??
Above grade takes one solution, below grade another.
2" of foam is kind of thin for Toronto.
24" on center is OK for sheetrock. Instead of strapping as stated, use one or two inch glued to smooth concrete wall. Over that apply 1.5 inch with notches as you describe for straps. Total 2.5 or 3.5 foam and apply sheetrock flush to foam. No vapor barrier next to outside wall, but a layer of plastic just before the sheetrock.

Any electrical on that wall will need special detailing.

Bud

Correct, my house is made of double walls, One wall is the brick, air gap then second wall (interior) is made of some kinda block/brick. Reason I wanted to go with the method i linked to above is to save space. My house is already narrow as it is, so every inch counts. 2 inch pink rigid insulation gives an R10 rating. I figure it is better then the lathe/plaster that is there now.

Most houses around here have 2x4 framing with R12 insulation.( newer houses ) The combination of my double walls with air gap and the R10 rigid insulation should give me a pretty good seal.

I just don't know if I am allowed to do this on above grade, I don't want to break any laws..

Above grade all the time. However, your local AHJ (authority having jurisdiction) always has the last say. You should ask if you want to be certain.

Here are some similar wall assemblies:
http://www.buildingscienceconsulting.com/resources/articles/Understanding_Vapor_Barriers_ASHRAE_2004_08.pdf

Bud