Hi,
Have gutted daughter's room in basement(actually one exterior wall). This wall had efflorescence on it and some of the furring strips had water damage o0n their bottoms near the floor. The moisture problem has been solved(New eavestroughs) and grading away from the house.
The problem is that I want to insulate the wall again, and place drywall over top, but the wall is not totally square, i.e. it is not level. I was going to use rigid foam board, and glue it to the concrete, but the bottom part of the wall indents in some places about and inch or so...
I guess I can build up a 2X4 wall one inch away from the concrete wall, and then put in batts and a vapor barrier, and then drywall.
But I was also considering having polyurethane foam sprayed directly on the wall(about 2"), then building out a 2X3 wall and finishing with vapor barrier and drywall.
What would be the better choice and if I were to go with the spray foam, do I build a 2X3 wall one inch away from the concrete, then spray so the spray gets under the 2X3, or do I spray the whole wall 2" thick, then build the wall over it?????
I am confused, and hope I didn't confuse anyone....I live in Quebec, north of Montreal.
Thank you.
George, a proud dad of a U.S. Marine

p.s. the reason I was thinking of the spray foam is that it can get into all irregularities, and part of this wall has a closet that has a wierd shaped wall.

 

geoss,

Since you are already aware of previous posts on how to do the traditional wall with batt insulation I am unsure if the spray in place is going to be a lower cost per foot as you would have to apply 1 1/2" of foam minimum to meet R-11. I assume that you ahve done this but I think the foam will cost more.

Also, any irregularities aren't even a consideration when applying insulation to a basement. Everyone has them but as I have pointed out in posts, you aren't concerned with the ins and outs but the "envelope" package of the entire system when done.

Just a note, foam insulation is relatively hard to ignite but when ignited, it burns readily and emits a dense smoke containing many toxic gases. The combustion characteristics of foam insulation products vary with the combustion temperatures, chemical formulation, and available air.

Because of the dangers described above, foams used for construction require a covering as a fire barrier. One half-inch thick (1.27 cm) gypsum wallboard is one of the most common fire barriers. Some building codes, however, do not require an additional fire barrier for certain metal-faced laminated foam products.

Check with your local building code/fire officials, and insurers for specific information on what is permitted in your area.


Hope this helps!

 

Hi,
The spray foam will be more than the traditional batts, but if I do go with either method, should I Dry-lock the wall. There is asphalt half way up the wall, but in some places it has broken off while removing concrete nails previously. I already have a gallon of the Dry-lock paint. Thanks
George

 

geoss,

Are you saying there is asphalt emulsion on the inside of the home?!!

 

Hi Doug,
Yes, there is asphalt(tar) painted on half way up the wall...It's been there for 25 odd years or so.........what should I do about the Dry-Lock, since I have a gallon of it anyway..Do I just paint over the tar and continue up to the bare walls
I think I will be going with the 2X4 wall moved 1 " from the concrete wall, and use batts, and a vapor barrier(the reflective aluminized paper). Hope to be doing this soon, so would like to get opinions soon. Thanks alot.
George

 

geoss,

This fast enough for you!?

I would not apply the DryLok to the walls as the asphalt emulsion virtually makes Drylok useless.

This is from Drylok;

"As in any painting job, surface preparation is a critical step. Loose or broken mortar, dirt, dust and other foreign matter should always be removed before putting on a new coat of paint.
Before applying the waterproofer, clean the surface thoroughly. DRYLOK® works best when applied to a clean, bare masonry surface. It may be applied on a slightly damp surface but best results are obtained when applied over a dry surface. DRYLOK® should never be used on a wet surface.
Remove old paint by wire brushing, sandblasting or other suitable means. DRYLOK®Etch or muriatic acid should be used to rid the surface of efflorescence, white, crystal-like salt deposits that prevent the waterproofer from sticking to the surface. Holes should be patched with DRYLOK® Fast Plug® or a hydraulic cement."

Too much work to remove...leave it as is. Start your walls/insulation!

Hope this helps!

 

Thanks Doug,
Appreciate your quick response....just one last thing(hopefully)....
I guess the parts of the tar that has peeled off, or parts that are repaired because of broken concrete will be o.k. to Dry-Lok??????
The "foam" insulation guy keeps telling me how the foam will reduce humidity in the basement. Will it do anymore reducing of humidity than Dry-Lok where applicable,a 2X4 frame set 1" away from the wall, and then R-13 covered by the paper/foil vapor barrier?
Appreciate it.
George

 

geoss,

I think in your situation, using foam is an overkill and it isn't cheap. You have an asphalt emulsion on the walls which in itself reduces moisture and if this has peeled away in spot, you could do the drylok where you think you need to put it. But like I said, the surface must be clean! Just because stuff is peeling away doesn't make it clean.

If I understood your initial post, this foam application was going to be for one wall only, not the entire perimeter of the lower level, right? Doing just part isn't going to help much at all. If you don't hanve any moisture problems now, why even consider it? Foam isn't cheap and it is only an R-6 or 7 at best per inch. You walls with batt insulation is an R-11 minimum and you could use R-13 for pennies per square foot vesus foam! What is the cost for the foam per inch?

Why do this, pay more and achieve virtually no gain in doing so?

Foam does provide protection from moisture and air infiltration but what about the rest of the basement? I think it is overkill if you are not doing the entire perimeter and if you do the entire perimeter or just part, IT MUST ALL BE PROTECTED BY A FIRE BARRIER - 2X4 WALLS/DRYWALL AS PER CODE. You must be able to protect all of the sprayed areas as this stuff is very TOXIC when fire hits it.

Hope this helps!

 

Hi Doug,
Thanks again, You make ALOT of sense. No, it would be only covering the one wall in the bedroom, so a continuous foam barrier wouyld not result. I will use something called "Roxul" up here in Canada....It comes in batts but has a little higher insulating value and is not affected by moisture...... The rest of the basement has depending on where it is 2" of the white styrofoam, and other places up to R-20 or so.....So foam in one place would not make a big difference.

Doug, one more piece of help , please..the room next to the one I am doing is 19' long and has the one long exterior wall and 2 closets with exterior walls. The insulation there is 2 inches of the white beadboard stuff used about 20 years ago. The room is finished with drywall and newly ainted. That room is also the one that is most undertground.
My question is , please, do you think it would be worth it to tear down the drywall in this room, remove the white styrofoam, and furring strips(what a mess), and then build up a wall and do the 2X4 with batts as in the other room.......This is alot of work and expense...would I gain anything over the white beadboard and drywall that is presently there......I really appreciate your help...Just to mention again that particular room is the deepest underground......
Thanks for your patience.
George

 

geoss,

You're welcome....

The question is...is this room currently warm enough to you? If you know all that is on the walls already, I assume that you have been looking at different things.

I think that the 2" white foam board is only about a R-6 total but if the room is already warm enough, why tear it all out and redo?

If the room is not as warm as it should be, are there other issues besides insulation improvments...like your heating system that should be looked at as well?

Before going to much further, maybe a good HVAC guy should look at what you have and determine your needs based on what you have or intend to do. Then make your decision based on this.

I would improve insulation if all other factors are found to be satisfactory and the need to insulate would improve things overall. Also is this room going to be used alot or occassionally...what is the purpose fo this room? This plays a role in what kind of investment are you willing to make.

Think about it....

 

Thanks alot, again, Doug....
No, the room is not used frequently, and there are 2 ducts in the ceiling of which one I close completely and the other one I close quite a bit down....I just cannot imagine tearing all that drywall out, and renovating...I was just thinking that it would reduce the humiodity a whole lot because the basement humidity goes up in the summer, and I would like it lower. Even though we have a/c, we don't open the vents too much because the cold air going down really makes ther basement cool...Thaanks.
George

 

geoss.

You're welcome! Ever think about a stand alone dehumidifier - got a floor drain close? Have it drain directly into that. This way your humidity should stay withn reason.

Just a thought!

 

Doug,
Do have stand alone de-humidifier, but lent it to mother in law.....but she never uses it....will get it back and hook it up to my drain....I believe this'll be alot cheaper than 600$+ for spray foam on the walls.....
SO....do the bedroom wall with 2x$'s and leave the wall in the other room as is...........unless I get bored next winter or this summer and feel like teariong more down..YUK!. Thanks
George