furring strips or 2x4s against concrete basement wall?

denemante

Hey all - finishing my basement. We live in Atlanta so you get an idea of the temps.

Several walls are floor-to-ceiling concrete. It's been painted grey, and my guess is that it was some sort of sealing paint. Looks pristine. No cracks.

I want to maximize space. A friend suggested just gluing greenback drywall to the cement. I can't imagine doing that - plus the concrete isn't perfectly even. So....

• I could use furring strips screwed into the concrete so I'd have something to screw the drywall into (not sure, maybe greenback or not). Their shallow depth would maximize room.
• I could just frame with 2x4s laid against the concrete. But in this and the option above - can you just lay normal, untreated wood against the concrete?
• I could frame my 2x4 wall perhaps 2 inches (or further) away from the concrete (producing a void). This option stinks because I lose a lot of space and I hear the convection of air in voids is bad news.

Finally - I haven't even mentioned insulation. With any 2x4 framing option - I coulld put normal insulation into the cells. But if my framing is against the concrete - so will be the insulation. Perhaps that's bad news.

I've seen the foam panels. On TV - I've seen guys glue that to the concrete, then tape up a layer of immaculately sealed plastic barrier, then frame on top of that - and still put in insulation into the stud cells before greenback drywall!

Finally - this area is presently not temperature controlled - yet remains about 60 degrees all year round. It's dry. So I fear that when I stud, insulate, and drywall - I'll actually be keeping this warmer, soon-to-be temperature controlled air away from the concrete. Now - those same warmish concrete walls will take on the temp of the land outside - and then they could bleed moisture.

Help!

oh'mike

What is your question?----

You are way over thinking this---I suggest standard 2x4 framing held 1 inch from the foundation.

This will give you---a flat wall---room for proper insulation---electrical and utilities--

The loss of space is minor while the quality of construction and ease more than make up for that loss.

--my 2 cents---mike--

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DrHicks

I agree with Mike. Frame up a 2x4 stud wall. Insulate, use the proper vapor barrier, and drywall it. You won't be sorry.

If you can't afford to lose the 3" of floor space this will take up, you don't have a room big enough to finish anyway.


Good luck!

tcleve4911

Absolutely don't attach anything to your foundation

Oh'Mike and the Doctor are spot on...2x4 with 1 inch separation.

dtsman

I am going to Assume that you know what you should do, based on what your neighbors have done in your area. You are just looking for a cheap/temporary option. Based on that..

I wouldn't use furring strips at all. 2x4 would work great depending on the R value of insulation you want to use and running electrical. In Atlanta, you would be ok with a pressure treated board for a base plate sitting on the floor without that 1" clearance thing. If you don't care about insulation or electrical, build it out using 2x2s. Liquid nail the base plate to the floor and then nail the top plate to the floor joist above for simplicity and avoid putting holes in the sealed block wall.

But no matter what drywall type you use, VERY IMPORTANT, it will need some airflow or climate control down there and possibly a return vent as well, depending on how it opens to the rest of the house. If you trap moisture down there you will get mold.



Bo

Remember,
If the women don't find you handsome,
they should at least find you handy.
(Red Green)

DrHicks

^^^ Wow - interesting that you mention "return vent."

I've recently been going with a family friend to look at houses. She wanted more opinions than hers before she jumped.

One thing that really surprised me was that several of the houses we looked at did NOT have any cold air returns in several of the rooms. And a couple of the houses had new furnaces & ductwork. What the heck?

denemante

Dr. Hicks - what is a vapor barrier? I mean, I get the idea from the name. But where and how is it installed?

And would I just use it in the areas over the concrete? I have already studded walls down there too - some are outside walls.

Finally - is there special insulation or drywall (like the greenback) I'd need to use anywhere?

DrHicks

Vapor Barrier is 4 mil plastic (check local code) that you put up between the stud wall and the exterior concrete wall. (There is lots of debate about vapor barriers, actually.)

I'm not sure whether I'd use greenboard or not. If you have moisture problems, you'll eventually have problems with the greenboard. It's water resistant, not water proof. Plus, on 16" centers you're supposed to use 5/8 instead of 1/2. So in my opinion, that's a toss-up.

I think it's your choice if you want to stud over all exterior walls or not (regardless of whether they're concrete or stud walls). Studding in the whole thing would be simpler and probably make for cleaner lines. But that's just my opinion.

mrgins

This is a question rather than an answer, and from a northerner, but why wouldn't 2" of styrofoam with furring strips laid over the top not be a solution? The foam would be glued and the furring screwed to the concrete

DrHicks

Sure, that's a solution. In fact, in a couple weeks I'm going to be doing that very thing in a very small basement bathroom, where I actually cannot afford to lose the 3" that a 2x4 studded wall would take.

But my personal opinion is that it's not the best option, though I'll openly admit that that is just my opinion.

pyper

Around here there's usually only one, or maybe two returns per zone.

I suppose the advantage to more returns is being able to keep doors closed.

I saw a neat basement insulation system on TV. It was (roughly) 2" blue foam with grooves on the ends. You put a 1x3 in the groove and nailed it to the concrete with one of those nailers that fires 22 caliber blanks. The 1x3's were 24" on center (I guess) for the sheetrock. I was thinking about using that in my basement, but they didn't say who made it. Anyone know?

bethomas

One thing to think about is that furring strips can be a PITA if your basement walls are not square. The previous owner of my house did that and when i tore everything down to redo the basement, i did standard 2x4 framing. i have 1"-4" between the bottom plates and the walls in some places. Also, some of my walls aren't perfectly plumb either, so by doing my own framing i was able to get square, straight walls, with standard insulation and vapor barrier behind it. Also, my basement would stay a pretty consistent temp too year round, but i have installed AC and returns in the basement as it can get warm down there if we are hanging out watching football or something. it also keeps the air moving (and has the wonderful effect of pulling in the smell from the cat litter box throughout the house - nasty damn things)

This basement is pretty small. approximately 11x20 on each side of the stair case.

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DrHicks

That's a good point - and is part of what I'm looking at in my basement bathroom. The house was built in 1928 and is rock solid, but the concrete block walls are not perfectly straight and level. Because of that, I'm going to be doing a lot of "pain in the butt" shimming and tweaking in the bathroom, that I did not have to do when I finished the other rooms using 2x4 stud walls.

bethomas

at least you didn't have to redo both your sump and sewage ejector pits! i put in a proper ejector pit and the sump was in the middle of one of the rooms so i move it back over by the foundation walls

denemante

Is there some product that could be both a vapor barrier AND insulating? Like foam board that could be glued to the concrete, then have the seams taped?

I do plan to run 2 vents and one return to this area. The other half of our basement is already finished and separated by french doors. As I noted - this unfinished side stays comfortable without any heat/cooling, but it's just the right thing to do to run new vents.

But all this said - I feel like I really don't need much insulation. The drywall will have some R factor I'm sure. And since the room hovers mid 60s all year round without any air - once I add vents and a return - I'd think I could bring that to 70 year round no prob.

But back to the vapor barrier - it scares me a bit. My basement stays bone dry. I'm fearing that a vapor barrier might then trap moisture behind it where mold would grow. If I don't use one and let it all sort of breathe - what's wrong with that?