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harddy 11-29-2009 11:05 AM

Framing & Insulating basment concrete walls
My home is 30 years old and the basement was framed and insulated incorrectly for today's standards. I am tearing it all out and redoing it. The concrete is damp on the inside. I plan on waterproofing the outside foundation in spring. My question is can I do all of the interior work(framing, insulating and poly) prior to the waterproofing the exterior? Or do i need to do the exterior and have the interior open for how ever long it takes for the concrete foundation walls to dry out then do the framing and insulating?

ccarlisle 11-29-2009 11:14 AM

Look, a lot of what you do in terms of insulating or framing your basement depends almost 100% on what codes you have and most importantly what area of the world you are located in that those codes apply to...I mean what the heck is the point of my telling you to put a 6mil poly vapour barrier on the inside (warm) of your insulation if you live in Florida? What? because that's what I do???

Tell us that - at least - and the specific climate you live in what your basement is made of, what you walls are made of, what you want the finished part to be and perhaps then we can tell you what the general consensus of opinion is in your neck of the woods...


harddy 11-29-2009 11:21 AM

I live just outside of Winnipeg, Manitoba. I am putting rigid foam onto the interior first, then framing against that so the wood isn't touching the concrete and filling the framing with insulation, then 6 mil poly all taped and sealed and covered with drywall.

ccarlisle 11-29-2009 11:41 AM

:thumbsup: Jeepers sounds like a plan to me - for someone in the 'Peg. Make sure you seal the panels to each other using sealing tape, and foam around them all. And pay attention to the rim joist area because that's where we, up here, have a big problem with air exfiltration...

But first, let the concrete dry out a few days, not that this'll make a big difference if you have other water issues but it will help. Turn on a dehumidifer if you need to. What's on the floor? Don't stud to the concrete floor without a sill gasket foam.

I'll bet a few bucks that someone from Oklahoma, or Seattle will read this, take it for something that they should do and give me grief over it...:whistling2:

Incidentally, you may not need poly...

wtdug 12-01-2009 05:18 PM

Ref Basement re-modeling the question I had was in relation to framing. First I live in Ottawa (Canada). When my basement was refinished, the contractor installed a sub-floor, then when he framed the walls and put them out from the concrete basement foundation about 1-2" to allow for any excess moisture, etc from becoming in direct contact with the framing or insulation. From there all the wiring, cabling, etc is run behind the framing, and in between the framing (16" on centers) was insulated with Roxal insulation. Once all that was finished he put a vapor barrier (6mil plastic) with apply sealant (chalked the plastic at the top/bottom of the framing) and finally the drywall.

The question I have should I be concern about excess moisture forming between the basement concrete wall and the air gap (1-2") before the framing, insulation, vapor barrier, etc. is???? --- Or is this procedure fine.


stadry 12-02-2009 03:35 AM

not a helluva lot of difference 'tween 'peg, ottowa, & upstate ny far's bsmt finishing but here's what i'd do & did in mine.

exterior above grade - 1" blue board foam glued to pressure wash'd exposed foundation walls,,, xpanded wire mesh over that follow'd by 2 parge coats.

interior - hang 6mil poly from top of the block walls down to & behind the miradrain left exposed when we installed the ' french drain ' under the floor & alongside the footer's btm elevation - that way ANY vapor would condense & drain down into the pipe & find its way to the sump/pump,,, we then glued & shot p/t sole plate 6" from block walls & blt stud walls about the interior,,, unfac'd insulation bats 'tween the studs,,, finish'd walls were geo-pacific sheet rock w/wall paper already attached for the top 1/2,,, 1" 6, 8, & 10" boards set at 35 degrees slant for the btm 1/2,,, we also installed 6 whisper fans for air circulation between the walls - 3 pushing & 3 sucking - there were in the unfinish'd area ( laundry-storage-mechanical )

floor was 2x4 p/t sleepers w/3/4" t&g 5ply marine plywood over them follow'd by carpet on top.

maybe o'kill but it was OUR home & i could ALWAYS see the work from MY house :laughing:

ccarlisle 12-02-2009 06:46 AM

Actually and based on my limited experience, one difference is in the actual construction of the foundation walls; I can't remember the last time I saw concrete blocks in a home, as most of us have solid concrete perhaps due to the greater pressures on the walls from freezing etc. I am not sure of this however...

But in Ottawa (my home town), your contractor applied the standard insulation technique and although there are better methods nowadays, I don't think you should be concerned about moisture in that air gap. After all we don't necessarily have to have a dry wall (not possible anyway), but we have to manage the moisture once it comes in. You'll see that during the winter the heating system will ensure that the inside air of your home is relatively dry (typically around 30% RH @ 20 deg C) so any moisture coming into your home isn't a problem as long as it is fanned around and distributed throughout the home.

Moisture will only be called 'excessive' once it reaches 70% RH at room temperatures and where there is no air movement; mould or rust could happen.

So your procedure is OK; not the best - but popular because of the affordable cost.

stadry 12-02-2009 08:11 AM

surprising to me, there're many homes blt in & around the atl area w/CINDER blocks let alone conc blks,,, naturally most of the better homes feature conc fnd walls ( 8" ) w/few crks here & there but not common,,, as i recall, aci only calls conc WATERPROOF if its 5,000psi compressive,,, i may not have total recall, however :laughing:

Gary in WA 12-02-2009 12:04 PM

When you space the air gap at foam board/concrete, be sure to seal the chase every 10' horizontally and vertically as per fire code.... IRC 602.8 Otherwise if an electrical outlet causes a fire, it would have a clear unobstructed run to spread in the walls and pop out another outlet box. This lists the different fire-blocking materials suitable, page #4: This is also Your Canada Building Code Check, minimum standards, very handy, for your free copy:

Be safe, Gary

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