Insulating/framing basement perimeter walls

[JDMMAN]

Having done some research on Home Depot, Rona etc they all show to use polystyrene sheets, vapour barrier and 2"x3" to insulate the walls. Is that up to code in Calgary?

I thought you needed to use vapour barrier, 2"x4" and then use either batt or sprayfoam to maximize basement insulation value?

For those who've recently insulated their own basement, how did you do this?

[autosm]

If I was doing it I would put 1" polystyrene against the concrete then 2x4s with R14 if you are going to develop it. I would still put a 6mi vapor barior under the drywall. I am not sure it the polystyrene can touch the concrete? I know the 2x4s and the batt insulation is not suppose to touch concrete.

[kenny]

If I were doing my basement, I'd just do 2x4 + closed cell spray foam. Air tight, no need for vapor barrier.

[CD007]

Originally posted by autosm
If I was doing it I would put 1" polystyrene against the concrete then 2x4s with R14 if you are going to develop it. I would still put a 6mi vapor barior under the drywall. I am not sure it the polystyrene can touch the concrete? I know the 2x4s and the batt insulation is not suppose to touch concrete.

[JDMMAN]

I was thinking of spray foam as well; however I would have to rough in all the electrical outlets etc first. Hence spray foam probably wouldn't make sense. Plus in terms of material costs, looking at ~$3 sq/ft of area covered in spray foam. (2lb closed cell)

According to some of the DIY videos/instructions, a 6mil vapour barrier needs to be tapped up before 1" polystyrene goes up.

Not sure if you can have 2 vapour barriers though, I was thinking of using regular poly sheet over the R14 Batt insulation to seal it up before using drywall. I don't plan on drywalling until I redevelop the rest of the basement (40% developed right now).

[CD007]

Why is there a problem doing electrical before insulation?

You'll need to do it prior to drywall anyways.


And 2 vapour barriers are bad. Condensation will occur between the two.

[JDMMAN]

CD007 - I plan on leaving the insulation visible (not drywalled in yet). I have plans to redevelop the whole basement in 2-3 years; currently 40% of the basement is developed and 60% undeveloped which I plan on insulating and framing. Hence not doing the electrical rough in/drywalling yet.

So question is if I can do the following:

vapour barrier tuck tapped to concrete wall
1" polystyrene
framing/R14 batt
poly sheet

or:

1" polystyrene "glued" & tuck taped to concrete wall
framing/R14 batt
vapour barrier over framing + batt insulation

[C_Dave45]

Originally posted by CD007
Why is there a problem doing electrical before insulation?

You'll need to do it prior to drywall anyways.


And 2 vapour barriers are bad. Condensation will occur between the two.

x2. Electrical is always done before insulation.

As to the "moisture sandwich", normally you would not want 2 vapour barriers, but it depends on how his foundation walls were built. The new homes completely waterproof the outside of the concrete before backfill goes in. The older homes weren't done like this. So some moisture does come through the concrete. The new homes simply use 2x4 framing, placed about 3 inches from the concrete, batt insulation, 6mil poly, and drywall. On an older home, it is good to first put a vapour barrier against the concrete...THEN 2x4 framing away from wall, batt insulation,poly, drywall. A good publication is Canadian Wood Frame House Construction (<-- download link) as well as A Guide to Fixing Your Damp Basement (<-- sorry, couldn't find a free download link) Both put out by the CMHC.

[Sugarphreak]

...

[510-Trevor]

Originally posted by JDMMAN
CD007 - I plan on leaving the insulation visible (not drywalled in yet). I have plans to redevelop the whole basement in 2-3 years; currently 40% of the basement is developed and 60% undeveloped which I plan on insulating and framing. Hence not doing the electrical rough in/drywalling yet.

So question is if I can do the following:

vapour barrier tuck tapped to concrete wall
1&quot; polystyrene
framing/R14 batt
poly sheet

or:

1&quot; polystyrene &quot;glued&quot; &amp; tuck taped to concrete wall
framing/R14 batt
vapour barrier over framing + batt insulation

The vapour barrier ALWAYS goes on the warm side of the insulation.

[C_Dave45]

Originally posted by 510-Trevor

The vapour barrier ALWAYS goes on the warm side of the insulation.

He's got it on the warm side...in both scenarios. What he's asking is if he should use a second vapour barrier against the concrete wall, before framing, batt, and 2nd poly vapour barrier. Which in some cases is recommended.

[C_Dave45]

Originally posted by Sugarphreak


I am doing mine fairly soon, and this is exactly how I plan on doing it... spray foam is awesome!

And awesomely expensive! Like around $5,000 awesome.

[JDMMAN]

Thanks for the help guys. I need to now find a concrete nail driver to do the framing. I'm thinking of using Bluwood for this framing project.

[Sugarphreak]

...

[reijo]

Poly on warm side and you do not want a double barrier (can you say mould?).

Also for a bottom plate (if using 2x4 framing) use PWF wood - pressure treated OR a 6mil poly under bottom plate so the bottom plate does not rot out. It is also req'd by ABC.

R

[Porsche_55]

Originally posted by C_Dave45


He's got it on the warm side...in both scenarios. What he's asking is if he should use a second vapour barrier against the concrete wall, before framing, batt, and 2nd poly vapour barrier. Which in some cases is recommended.

"in some cases recommended"? Are you kidding me. Never ever do you do a double vapour barrier. The reason being is air flow thus mould. Granted there is not much air flow between the 2x4 wall and the cement wall the moisture can evaporate. The reason for the vapour barrier is to actually keep moisture in the house and not condensing inside a cold wall and causing mould.
Poly the warm side of the wall only and you need a separation between the cement flooring and the 2x4 wall Just a strip of poly on the bottom of the wall will do.
The guy that’s spray foaming his basement, your an idot. Its not cost effective and you won’t feel that the space is any warmer. The biggest heat lost in the basement is the floor. Save the money from the foam and put some slab heating in there.

[C_Dave45]

Originally posted by Porsche_55


&quot;in some cases recommended&quot;? Are you kidding me. Never ever do you do a double vapour barrier. The reason being is air flow thus mould. Granted there is not much air flow between the 2x4 wall and the cement wall the moisture can evaporate. The reason for the vapour barrier is to actually keep moisture in the house and not condensing inside a cold wall and causing mould.
Poly the warm side of the wall only and you need a separation between the cement flooring and the 2x4 wall Just a strip of poly on the bottom of the wall will do.
The guy that�s spray foaming his basement, your an idot. Its not cost effective and you won�t feel that the space is any warmer. The biggest heat lost in the basement is the floor. Save the money from the foam and put some slab heating in there.

How do you propose he install slab heat to an existing slab? Install a $10,000 boiler system and re-pour the slab? Jackhammer up the existing slab and install boiler system? The temp in the soil below the frost line is around 2-4 Celsius. There's not a whole lot of lost heat. While foam is expensive, saying an person is an "idiot, it's not cost effective" is simply put, wrong.

But since we're all such idiots here, and I really don't know anything about construction and renovation (30 years in construction) perhaps you could explain CMHC's guidlines of insulating foundation walls when there is no waterproofing on the outside wall as explained here:

Where insulation is applied to inner surface of foundation walls, the below-grade portion of the insulation and any associated wood strapping must be protected by a moisture barrier in the form of a 2mil polyethelyne film.....

there is two moisture barriers. One against the concrete, and then another behind the drywall.

[Porsche_55]

Originally posted by C_Dave45


How do you propose he install slab heat to an existing slab? Install a $10,000 boiler system and re-pour the slab? Jackhammer up the existing slab and install boiler system? The temp in the soil below the frost line is around 2-4 Celsius. There's not a whole lot of lost heat. While foam is expensive, saying an person is an &quot;idiot, it's not cost effective&quot; is simply put, wrong.

But since we're all such idiots here, and I really don't know anything about construction and renovation (30 years in construction) perhaps you could explain CMHC's guidlines of insulating foundation walls when there is no waterproofing on the outside wall as explained here:




there is two moisture barriers. One against the concrete, and then another behind the drywall.

Moisture is different than Vapour. The moisture barrier is for areas with higher water tables and to help with flooding your basement. Vapour barrier is to keep moisture in the home. In calgary its not common building practice to have moisture barrier in the basments becuase we dont have issues with water tables. Your picture isn't actually

"(30 years in construction)" installing carpet doesnt count. And in alberta we dont install studs sideways

So to re-cap DOUBLE VAPOUR BARRIER BAD

reijo Knows whats going on.

Oh and there is a mat that you can put down in the concrete floor that can you pure a thin layer of cement on top of that acts like a in slab heating. So no the $10000 is not needed.

[Porsche_55]

^^

"Where insulation is applied to inner surface of foundation walls, the below-grade portion of the insulation and any associated wood strapping must be protected by a moisture barrier in the form of a 2mil polyethelyne film....."

Not part of the ABC

[C_Dave45]

Originally posted by Porsche_55




Moisture is different than Vapour. The moisture barrier is for areas with higher water tables and to help with flooding your basement. Vapour barrier is to keep moisture in the home. In calgary its not common building practice to have moisture barrier in the basments becuase we dont have issues with water tables. Your picture isn't actually

&quot;(30 years in construction)&quot; installing carpet doesnt count. And in alberta we dont install studs sideways

So to re-cap DOUBLE VAPOUR BARRIER BAD

reijo Knows whats going on.

Oh and there is a mat that you can put down in the concrete floor that can you pure a thin layer of cement on top of that acts like a in slab heating. So no the $10000 is not needed.

That's not called "slab heating". That is called "in-floor heating", installed and supplied by yours truly. "Slab heating" is a completely different term. I've been installing "in-floor heating" for over 20 years, including in the actual home of the inventor of the first brand of it, John Ames of NuHeat fame. It is also extremely expensive to run for an area as large as an entire basement floor. Original install costs are around $10-15/sq ft. What was that about $10,000 again?

First of all...I don't install carpet, never have, never will.
Secondly, I'm quite familiar with moisture/waterproofing procedures..I build steam showers for a living and my livelihood depends on how my projects last.
Thirdly...whats your trade again?....A municipal worker behind a desk in the city permit dept? Yeah I've seen how "city building codes" have performed in the real world and how they usually change only after disasters hit the end-consumer. (see codes pertaining to stucco and building envelope procedures and the billion dollar damage done in BC and is just about to hit Alberta as a result of its original min code required on stucco thickness and wrapping method).

Your sentence "two vapour barriers always bad" is correct. We refer to it as "moisture sammich". And is disaster when there is nowhere for the moisture to go, evaporate. But in a old basement, where there is no waterproofing on the outside, having something to stop moisture wicking into the studwork (installing sideways is completely irrelevant to our discussion) is advantageous if done correctly. Read carefully you'll see there IS an escape route for the moisture in the diagram. No matter whose codes you're using, the diagram has some merit to the OP's original question.

Now...get back to your desk, sharpen your pencil, and keep those fingernails of yours manicured. And keep your snotty, facetious comments to yourself.
I'm going out to build another (my 1,000'th?) steam shower in a fellow beyond'ers basement.


Here's a little test for ya. I'm about to build a steam shower on a second floor bathroom, located in the corner of the house. Customer would like to use Denseshield as the board. What framing/insulating/water barrier method/procedure should he use on those walls? Both behind the tile as well as behind the wall itself. (No googling, either)