# Framing in basement attached to concrete blocks, how to insulate?



## drnormie (Nov 24, 2008)

We are finishing off the walk-out basement and running into some problems. 

We needed to replace the basement windows with egress windows and my husband was nervous about cutting the concrete blocks himself - so we hired a contractor. We then hired the same guy to frame in the two basement bedrooms.

We were planning on using fiberglass insulation and paneling to finish off the basement. However, the contractor installed the 2x4's directly to the concrete blocks with the 4 inch side against the blocks. 

Never seen this before, and from what I've read on this forum, it is not a good idea. What do we do? Do we tear it off and start over? Do we leave it and insulate with foam board? If we insulate with foam board - we have to drywall correct? (For fire code?) 

Thank you in advance.


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## bjbatlanta (Jul 16, 2008)

First off, did he use pressure treated 2"x4"s ?? They should be for direct contact to the block. I personally would not have, or pay for this type of framing (unless you agreed to it ahead of time unwittingly). The proper way to frame your walls is to stud up a regular 2"x4" wall inside of the block wall. This will allow you plenty of room for any electrical and plumbing needs, as well as allow for R-13 batt insulation. You COULD use rigid foam for insulation. Even at 1-1/2", I don't think the R value will be near R-13, plus you'll have to use thinner boxes for electric and running the wire will be a pain. As far as code, you would have to check with the local inspector. Whether it's code or not, you SHOULD use drywall over the foam. If you're thinking of 1/4" sheet plywood, you should back it with 1/4"drywall anyway to give it some rigidity.


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## kevin211mvd (Nov 9, 2008)

I just finished two bedrooms exactly like this. If you goto your local lumberyard or lowes or home depot the usually sell P-2000 foam insulation with an insulation value of R-40 It is 1" thick. Basially all you have to do is cut each piece to fit each bay usually you make it about 1/8 heavy of your original measurement and it will have a tight fit. Sometimes you will have little gaps on the sides if this occures you can use the cans of sprayfoam insulation to seal the gaps. As for electrical we had to use the shallow metal boxes that screw to the side of the studs. They look like a double box . They sell covers for them that are recessed out 1/2" for the sheetrock. The wireing is a little bit more tricky but usually you can run the electric in the floor system above or by the sill plate .


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## bjbatlanta (Jul 16, 2008)

I stand corrected on the R value of the foam insulation. And, as stated, the wiring can be more trouble but is do-able. Again, I hope he used pressure treated lumber for direct contact to the block......check your local building code. Best of luck.


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## drnormie (Nov 24, 2008)

I wish I had known he was going to do it that way... But it was our fault. We didn't ask the specifics, and came home from work one day and there it was. It was pressure treated lumber - fortunately.

Thank you for the tip on the P-2000 insulation. I too did not realize the foam could have that high of an R value. I will look into that.


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## kevin211mvd (Nov 9, 2008)

Yea the basement rooms worked out great.. would have been so much easier the other way but hey I didnt frame it. Its good to get those jobs though, you can learn new techniques..... Make sure you talk to your local building inspector before doing anything though... Over here everything passed inspection smoothly. But who knows, where you are there requirments may differ from here


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## Jack of most (Jan 21, 2009)

They should have left an air space between the walls. Good luck in preventing condensation. Whether you should remove what's there. Either finish it w/ sheetrock or paneling, then hope for the best. Or, spend the money and do it right, now. Construction costs will only go up in the future. Treated lumber should last longer than plain pine, depending on the amount of moisture it is subjected to. Retained moisture breeds mold and mildew. Foam board is good, but this requires a vapor barrior. A house wrap, which allows breathing, would be better than a plastic.


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## Scuba_Dave (Jan 16, 2009)

Where did you get the R-Value of the P-2000?
I found this site that says it perform as as well as 6" insulation - which would be about R21 maybe at best (which is still great for 1")

http://www.p2000insulation.ca/testing/performance_debate.php



> *P2000 exceeds Energuide expectations on performance*
> When this new home was complete, it was tested by EnerGuide. The technician credited P2000 with an insulating R-value of R-5


However it performed 20% better the expected



> After monitoring the energy consumption for the home for more than a year, the house is using significantly (more than 20%) less energy than projected by the EnerGuide report.


Is 20% better R-6 ??
I couldn't find anything on the site that stated any actual RValue
I've never heard of any foam board with R40 at 1" thickness?


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## mrgins (Jan 19, 2009)

Scuba_Dave said:


> Where did you get the R-Value of the P-2000?
> I found this site that says it perform as as well as 6" insulation - which would be about R21 maybe at best (which is still great for 1")
> 
> http://www.p2000insulation.ca/testing/performance_debate.php
> ...


There isn't any 1" foam with R40. Even at R6, the total R value is less because the 2x4's conduct the cold. I'd use rigid foam directly against the wall, but in northern climates you should insulate block walls no less than two feet below grade but up from the bottom of the slab to keep the backfill warmer and prevent frost from penetrating too deep down


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## Bob Mariani (Dec 1, 2008)

below grade moisture will travel from the outside to the inside. What did you use for a vapor barrier to prevent this moist air flow? Nothing was mentioned, but as posted be prepared to suffer mold by summer. Tyvek is a weather barrier not a moisture barrier and will be of no use in a basement remodel. Pressure treated lumber is only needed where it is in direct contact with concrete or a mason block wall. (sole plate is needed to be pressure treated) Above grade the moist air moves from the inside to the outside, so how was this different transfer handled. Seems to me you have many problems.


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## AtlanticWBConst. (May 12, 2006)

Jack of most said:


> They should have left an air space between the walls.


I agree with this point 100%.


Jack of most said:


> Whether you should remove what's there. Either finish it w/ sheetrock or paneling, then hope for the best.


It's already done. (FWIW - This is an example of why some people choose to hire an experienced & licensed General Contractor, over a "handy man", or simply a "contractor" - to ensure that things are done properly and to code).* 

I'd suggest (if possible),"trying" to make this work, without ripping all of it out "IF" you don't have serious moisture issues. (Why?: It would be a shame to waste that time and money). 

Some newer/recently-built homes, have the fortunate advantage of advanced water-proofing systems applied, and exterior drainage systems installed. Most of them possess extremely dry basements, with very low humidity & moisture content.

As stated, there is the big "IF":

The key issue is going to be "IF" you have had moisture issues in the basement. If so, you are asking for trouble, by installing materials directly against a concrete block wall that has high levels of moisture. Anything against such walls, will "wick" moisture into it. Obviously the result will be mold growth, etc....If this is the case: I'd suggest removal of the recently installed "framing", more research on your part, and then starting the process over (correctly).

As far as insulation goes, I'd strongly suggest NOT using fiberglass batts. Use ridgid foam insulation instead. As far as a moisture barrier is concerned (in basements), this has been discussed to no end on this site. Due to the fact that you have KD grade framing Lumber against the walls, I'd suggest no V.B. (If the studs get damp, they will have more of a chance to dry out).

As far as sheetrock is concerned, I'd suggest the use of the paperless, & mold resistant type sheetrock. *Densarmor Plus -*

Link: http://www.gp.com/build/stopfeedingmold/whatis.html


Good Luck.


* I'm not stating that "all" handymen or basic "contractors" (People that have given themselves that title) do not do things according to code, or that they do hack work. There are some that really know there stuff. However, you do take chances when a person/company is not licensed or certifed to do more advanced/complex home improvement, or living space - remodeling work.


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## jaros bros. (Jan 16, 2009)

I checked the p-2000 and it's a gimmick. I had never heard of it so I googled it. They have their own rating system. Fortunately after doing some more googling I found out that 1" of p-2000 has an R-value of 10.3. It was done by an independent company. Sorry, didn't save the webpage. Y'all have to be a little less gullible. 

Josh Jaros


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