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Basement floor finishing questions

post #1 of 13
11/16/12 at 7:28pm
Thread Starter 
I have been researching for days now figuring out the inexpensive, yet effective way to finish a basement. The best information I've found so far has been from this website, and more specifically this thread: http://www.avsforum.com/t/1307424/how-to-affordably-warm-basement-floors/30

So although I am not currently planning a home theater in my basement (have a newbie one upstairs already) I would like to pick the brains of what seems to be the most helpful group of forumites I've seen in a while.

I have no current moisture issues (24-hour plastic test went stellar) and have never had a leak or puddle in the basement in 6 years. So far my plan is to finish the basement using 1" XPS foam on the walls and 1/2" XPS on the floors, all sealed and taped. Then for the floor I am thinking of putting down 2 staggered 1/4" OSB ply boards.

Here is where I'm lost. Ideally I would like laminate for the flooring option, but the wife says carpet for the kids since the rest of our house is hard floors. So, carpet it is. My question is this: Can I carpet on a floating plywood floor? Do I HAVE to Tapcon it, because I'd really rather not put holes into the concrete if I don't have to...Also it seems like it would hurt the integrity of the moisture barrier the XPS creates...

Then, since the walls aren't load-bearing, could I build the walls up from the subfloor base rather than using PT bottom plates at the concrete level?

I do have one other question that actually relates to audio in case I decide to do a home theater down there. In order to save on cost I am planning to paint the entire ceiling (pipes,wires and vents included) black. Would this wreck the sound quality of a basement home theater?

Any assistance would be terrific and greatly appreciated! Thank you!!
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post #2 of 13
11/19/12 at 6:08am
OK, I'll take a crack it....
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I have no current moisture issues (24-hour plastic test went stellar) and have never had a leak or puddle in the basement in 6 years.

I fully subscribe to the "not if; WHEN" philosphy of basement water issues. Please do everything you can to minimize the possiblility of water and minimize any damage. I've had two floods. I'm guessing one was the 50 year flood and the other the 100 year flood, but they were three years, almost to the day, apart. I now have carpet in the theater area and eventually will get laminate in the rest of the basement. I AM EXTRA carefull when storms are predicted.
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Can I carpet on a floating plywood floor?

That's basically what I did AND I built my stud walls on top of the subfloor, so no need for PT bottom plate. Although, I used Dricore, not plain plywood.
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In order to save on cost I am planning to paint the entire ceiling (pipes,wires and vents included) black. Would this wreck the sound quality of a basement home theater?

Are you saying you will not drywall the ceiling? If that's what you mean, then, YES, this would TOTALLY wreck the sound quality of a basement home theater.
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post #3 of 13
11/19/12 at 6:39am
I finished my basement almost exactly like you are looking at doing. I used 3/4" foam everywhere (walls, floor) and 5/8" ply on top. After going through this I would make a couple of suggestions.

1) Use 3/4" T&G OSB if you can. The T&G will help hold the edges together. My 5/8" ply has so many waves in it it's insane. Even though I fastened it all down the edges still don't meet up very well. The OSB with T&G was actually cheaper than the 5/8" ply I used. The store helper talked me out of using it because of moisture. Though, if you think about it, it won't come in contact with concrete, and if your basement should happen to floor, you are ripping both products out anyway. Really wish I would have gone with my first instinct on this one instead of listening to the store guy. This is probably my number one, "if I could do things differently".
2) I would fasten the stuff to the floor. Yes, a bunch of holes in the concrete sucks but having your boards separate and creating a void under the carpet could be worse.
3) Use PL300 foam adhesive and use small circles on the back of the foam boards to attach them to walls and every other row on the floor. This creates like a small suction cup that will help hold the piece to the wall and keep it from moving on the floor.

Hope this helps.
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post #4 of 13
11/20/12 at 6:09pm
Thread Starter 
I was planning to go for a little extra protection as far as water goes just in case. I plan to put a vapor barrier down and THEN the XPS then the OSB T&G as suggested by Vanice. I will be Tapconing the whole thing down since that seems to be the suggestion I've gotten other places as well. The circular adhesive Idea seems smart and also probably uses a little less adhesive than the "s" method I've been using for the walls...

The ceiling painted black is "temporary" because I can get all the paint and use the sprayer for free. So I plan to get a few years out of that and then depending on our financial situation someday we'll complete the basement project.

Thank you for all the assistance!
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post #5 of 13
11/22/12 at 8:04am
Quote:
Originally Posted by tlogan6797 View Post

Are you saying you will not drywall the ceiling? If that's what you mean, then, YES, this would TOTALLY wreck the sound quality of a basement home theater.

Why do you say that? It would affect sound proofing but not sound quality. Its actually likely to improve sound quality by making the ceiling a more random, diffusive barrier.
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post #6 of 13
11/26/12 at 6:21am
Quote:
Why do you say that?

How would you measure response if it's random? Seems to me even repeated playings of the same source material may not respond the same way. I reckon if you want to get a professional calibration you could probably overcome the issues. You would also have to have equipment ($$$) capable of being calibrated to that degree. I'm guessing there's a pretty good reason I've yet to see anyone build a room designed by one of the proffesionals that hang out here that does NOT include a fullly treated ceiling. I'm just recommending best practices.

Ever been to one of those trendy restuarants (or even a 5 Guys) with the open ceilings? It's VERY noisy, you have to speak loudly to be heard and it's hard to hear. They do it on purpose to make it sound like more lively place. I don't think you want that in your theater. At least, I don't.
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post #7 of 13
11/26/12 at 10:27am
I think that's an apples to oranges comparison. The reason a professionally finished room would finish the ceiling would be for soundproofing and aesthetics (as well as an opportunity to put treatments like a coffered ceiling).

Having diffusion in a room is not the same thing as saying the playback response would randomly change every time you play something back in that room....
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post #8 of 13
11/26/12 at 11:12am
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The reason a professionally finished room would finish the ceiling would be for soundproofing and aesthetics (as well as an opportunity to put treatments like a coffered ceiling).

I think you find that the REAL reason for the double drywall + Green Glue and decoupling, etc ("soundproofing") is to lower the noise floor INSIDE the room so that you can hear the quietest passage without turning up the volume and then going deaf when the explosions kick in (i.e., for sound quality). The fact that it helps keep sound IN is only a happy co-incidence.

I'm no expert, but since we seem to be speaking hypothetically, having random diffusion in a room will at minimum be difficult to treat. Do you know what the results of pipes filled with water vs hollow pipes are? Can you predict that? Can you be sure that the response is exactly the same? Does anyone at your house run water or flush the toilet? How about HVAC? Do you have forced hot air? Do your metal supply/returm lines expand and contract? Do people walk above and flex different ceiling joists as they move around (along with everything connected to them)? I'm just pointing out that things in an open ceiling can change and could change the response.

MAYBE your results will be satisfactory.

It would be great if one the experts would chime in.
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post #9 of 13
11/26/12 at 11:51am
Quote:
Originally Posted by tlogan6797 View Post

I think you find that the REAL reason for the double drywall + Green Glue and decoupling, etc ("soundproofing") is to lower the noise floor INSIDE the room so that you can hear the quietest passage without turning up the volume and then going deaf when the explosions kick in (i.e., for sound quality). The fact that it helps keep sound IN is only a happy co-incidence.

That's a legitimate statement - but it doesn't imply your sound quality will be "totally wrecked" if you don't soundproof.
Quote:
I'm no expert, but since we seem to be speaking hypothetically, having random diffusion in a room will at minimum be difficult to treat. Do you know what the results of pipes filled with water vs hollow pipes are? Can you predict that? Can you be sure that the response is exactly the same? Does anyone at your house run water or flush the toilet? How about HVAC? Do you have forced hot air? Do your metal supply/returm lines expand and contract? Do people walk above and flex different ceiling joists as they move around (along with everything connected to them)? I'm just pointing out that things in an open ceiling can change and could change the response.

Again, legitimate concerns, but I don't agree with your original assertion that the sound quality will be totally wrecked because of them, any more than if you have a projector inside your room rather than outside of it (thereby raising the noise floor because of the fan), or if you are eating popcorn while you are watching the movie smile.gif

BTW random diffusion is, in itself, a treatment. Same thing if you have a living room with lots of bookcases, etc. Not as good as a purposely built diffusor, but almost certainly better than a flat wall, all else being equal.
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post #10 of 13
11/26/12 at 1:01pm
Quote:
That's a legitimate statement - but it doesn't imply your sound quality will be "totally wrecked" if you don't soundproof.

True enough, I'm willing to concede, but "totally wrecked," as asked by the OP, is purely subjective.
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post #11 of 13
12/5/12 at 4:01pm
Thread Starter 
One more question, not having to do with flooring or sound (well it relates to sound in a way I suppose)...I have my XPS boards up and I'm planning on putting my walls up with a 1" gap between the framing and the XPS. Now, I can get a really great deal on R-19 making it cheaper than R-13 and 15. Now, I realize that compressing the insulation reduces the R value, but from what I've seen and read even if its compressed 2" and put in a 2"x4" cavity it drop the R-value to about 13. I will be compressing it into a 2"x5" space, so I'm guessing it's going to be similar to R-15...

Should I increase the gap to 2" and lose that extra 2" (1" each side) of floor space across the whole basement (its an 800 sq. ft. basement) to gain the extra 3-4 R-value? I don't want to end up paying more money for the same R-value that I would get from the compressed R-19, and I prefer not to lose the floor space. Are there other issues with a wall spaced 2" from the XPS that I should take into account?

Just looking for some guidance from people who have more experience than I do in these areas.
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post #12 of 13
12/5/12 at 4:08pm
Thread Starter 
I just calculated the difference in square footage...I can definitely be okay with the 2" spacing since it really won't eat up a noticeable amount of floor space. Now my question really becomes, is it okay to space the framing 2" from the XPS? That should allow a good amount of air flow between the wall and XPS while still allowing the R-19 to fit pretty snug...I'm just getting anal about the whole project because I want to get it right the first time and be happy with the results!
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post #13 of 13
12/5/12 at 5:04pm
There's no issue with the framing being 2" from the XPS if you are filling the 2x4 studs with R-19.


Tim
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