Finishing Basement

[miguelacho]

I have been planning on finishing my basement and use part of it for my shop and part of it for living space. I have researched the subject somewhat and have come across different suggestions. I read in one place that I should cover all the walls as well as the floor with 2" insulation foam boards. I spoke to on of the subs that built my house and he recommended nailing/screwing pressure treated wood directly to the concrete walls in an horizontal arrangement leaving room in between boards for 1.5" or 2" insulation foam. I have also heard of using the 2 x 2 plywood flooring tiles with the dimpled rubber bottoms for the flooring or laying down a moisture barrier then making a floor from 1x3's.
So what is the best way to do it. I have a really dry walk-out basement (although we have only been here a year). I want to know what would be the best way to finish it. I am willing to do what it takes to do the job right short of breaking the bank!

Thanks in advance for your suggestions.

Miguel

[arcticfox46]

Miguel,

You should NOT attach directly to the concrete walls. You need air space between your interior walls and the concrete wall. Even though you have a nice dry walk out basement, you still need the circulation. The concrete is porous and the outside soil will contain some moisture. The air space will ensure circulation and drying of the concrete. If you don't leave the air space you will trap the moisture and rot the wood.

The sub you talked to should never be allowed to do any work in your house. He is trying to kill you. NEVER, NEVER, NEVER use pressure treated wood inside your house for any reason. Don't burn it either. It precipitates poisenous fumes into the air in your house.

Both of these things are basic stuff, and anyone building houses for a living should know about this stuff.

I did my basement about 10-12 years ago.

I first sealed the concrete walls and floor with thorough-seal concrete sealer. Then I ripped 2x4's in half and laid them on the floor 16" on center. I put foam insulation between them. I then put 3/4 plywood and nailed with galvanized spiral nails. Use Tounge and groove plywood.

I then made wall frame sections with 2x4's I made them on the floor with a top plate, bottom plate, and studs 16" on center. I lifted them up to a standing position and spaced them 1 to 1-1/2 inches from the concrete walls. Make them level and nail into the floor and into the ceiling joists. Insulate with regular R13 insulation.

Put 1/2 sheetrock and finish just like any other room in the house. I used suspended ceilings so I could have easy access above for wiring or plumbing.

[SuperDad]

I think that someone has misinterpreted what the carpenter said. I suspect he was trying to get vertical 2x3's or 2x2s attached to the wall, and to attach some sort of paneling to them.

As far as pressure treated inside a house goes, as long as its enclosed inside a wall as in this application, I think it is permitted. Check your local code. More than that, I think in my area that any wood in contact with foundation is supposed to be pressure treated.

I think everyone agrees that burning PT or its sawdust is a really bad idea. If the wood behind your basement walls is burning, the gases released are probably only a tiny portion of your problems :)

I would think it'd be better to lay these boards against the foundation vertically, so that if there is a little water seepage on the wall it can roll to the floor instead of pooling on the boards.

Note that my current basement has full 2x4 walls, mounted at the bottom to a plate that is attached to the floor of the basement, and at the top to a plate that is attached to the joists above. It sits a few inches away from the walls, both top and bottom. There is ~2" styrofoam insulation glued to the foundation walls.

I had to rip out a small portion of the wall to repair a sewage/rainwater leak recently (yuck), and found that there was about 6 linear feet of 2x4 that had been turned to rot. I replaced it with PT, sealed all the leaks, added a funky hidden trap door for monitoring, and made a place for water to pool(in theory at least) using aluminum angle iron.

[fifo28]

I redid my basement about a year ago. Similar to what other have posted. I first sealed the walls with drylock. Don't know how great it was, but it can't hurt. I then nailed PT 2x3 to the floor a few inches away from the walls. Put up 2x3 framing and secured it to the cieling joists. Stuffed R-13 or R-19 insulation between the studs and sheetricked (1/2"). Worked out great. The basement is noticebly warmer.

[arcticfox46]

I would be careful about getting the insulation too close to the concrete walls. If there is any condensation in the concrete and it gets into the insulation, it will render the insulation ineffective, and hold that moisture against the wood and cause rot.

However that is just my opinion. Heard it from some good home builders.

[Saurer]

I'm in the process of finishing my basement. Our code says that you need to use pressure treated lumber as the floor plate on all walls if it's going to touch the concrete. The newer stuff is supposedly safer then the older version.

As for insulation. I've been told not to use batt fiberglass against the basement walls, because it will trap moisture and create mold. Ask Paster Paul about how insulation can mold.

I used Dryloc in my basement as well. Not sure how good it will work. It cost me $65 to do it. I've seen $65 spent in a lot worse ways.

My brother and I didn't use any type of subflooring. We simply put down a heavier pad.

One major issue that can get overlooked is placement of heating/AC vents. The closer to the floor you can get them, the warmer/cooler the basement will be.

[Livens]

Hi, I'm finishing my basement too :)

I would agree with arcticfox46 that a gap should be left between the wall and the concrete. I have spoken with many contractors and they all say the same thing... mold, mildew, rotten 2X4's and soggy drywall will result eventually if you close that space up.

I too disagree with the pressure treated wood advise. Any wood sitting directly on the concrete floor should be pressure treated, so basically the bottom plate of all the walls. I could be wrong on this, but I think on January 1st 2004 the EPA banned CCA (Chromated Copper Arsenate) pressure treated wood for the most part. The Chromium and the Arsenic being the bad stuff. Now its Alkaline Copper Quat and Copper Azole, both of with are mostly Copper. I still wouldn't burn it or breath too much dust from cutting it, but you shouldn't worry about toxins leaching out from it. Here where I'm at it's code to use pressure treated in basements, rotten foundations are no fun.

When I was framing my bathroom I used Tapcon concrete anchors to hold my bottom plate(I think its called the plate?) to the floor. They work great are are a snap to install :)

As for the floor I would not build a subfloor. The same rules apply here as with the walls, it needs to breath. If your doing carpet DO NOT put down a moisture barrier. This will trap moisture and cause problems latter down the road. They sell carpet padding just for basements that can take a little moisture. All you need is this and whatever carpet you want. Any moisture coming from the slab will just evaporate up through the pad and carpet, this is a good thing. Moisture is not the problem, trapped moisture is. Buy a dehumidifier if you think its too damp. I went to Woodcraft and got one of thier hydrogometers for 6 or 7 bucks so I can keep an eye on my moisture levels, so far I havn't needed a dehumidifier.

Sorry for the long-windedness of my post :)

Good Luck!

[arcticfox46]

Miguel,

Please forgive my comments about the PT lumber. I don't know how hazardeous the NEW stuff is. My comment reflects the old stuff.

[miguelacho]

Thank you all for all your suggestions. Leo, no need to apologize. Your thoughts are greatly appreciated. It is the discussions and the varying opinions that make this forum so valuable.

So let me summarize!

Preassure treated wood (the new stuff!) on all places contacting concrete. This will mainly be the floor plates. The studs and top of walls attached to joists will be regular lumber. As for insulation that should be the hard foam and not regular insulation to avoid moisture. So I assume that this should be right behind the dry wall and away from the concrete to avoid moisture and allow air to flow. I also assume that no moisture barrier shoud be used.

I like the basement carpet pad idea for the part of my basement that will not be the shop, but what should I do with my shop since I do not want carpet there of course!?

Another question is what to do with the stairs. If I build those walls away from the foundation there will not be appropiate room left!

And finally (I promise this is the last question!) if in the "non-shop"/entertainment area of the shop, if I wantd to put wood flooring down, would that require a moisture barrier and or a subfloor?

Thanks again for all your suggestions.

Miguel

"Why are unfinished basements not counted as living area?
That's were I live!!!"

[Livens]

miguelacho,

For your shop space there are several options. You could use garage floor paint, comes in grey and white and Ive even seen some with black or white speckeles in it. Also you could stain the concrete then seal it with a clear coat. I saw a house where they did the entire first floor like that and it looked really nice. What I'm getting at is spend cheap in the shop. No sense spending 100's for a floor thats probobly going to get all scuffed up anyway.

The wood flooring is a no no, at least real wood is. The laminated HDF stuff "says" you can install it below grade. It will definatly need a moisture barrier. Any moisture coming up will certaintly rot it out, but the moisture barrier could trap moisture. To me your rolling the dice on anything that requires a moisture barrier, but lots of people do it so I guess its not written in stone.

But for my money I would use the stain & seal method.

Here they have some pics of stained concrete, really nice:
http://www.fabcrete.com/

Not supporting their product BTW, just for example.