Insulation recommendations and help..

R-13 for 2 x 4 walls (15" wide batts if you framed 16" OC stud spacing, 23" batts for 24" OC stud spacing). Kraft faced for vapor barrier if against outside walls (or block wall if in basement) with Kraft side facing in (towards heated side of room). General opinion here is R-19 for ceilings. Ted White says anything thicker in ceiling isn't worth it due to diminishing returns vs. money spent.
For inside walls of HT (room to room) as thick as will fit in the wall cavity without compression (no need for Kraft facing).

As far as brand, my opinion is to buy whatever is on sale.

Insulation for what? Sound attenuation or simply for insulation qualities?

Now come on Dennis, I don't imagine he came to this forum for how to keep his house warm, do you? After reading some of your posts lately, I'm thinking somebody needs to take a "chill pill." You've been giving such great advice for such a long time it seems out of character to be getting so petty.

Just a casual observation.

IMHO, Dennis's question is completely valid. I'm doing a basement build and will be doing insulation for both warmth (around perimeter of rooms by block walls) and sound isolation (ceiling and inside wall-to-wall areas). OP could be asking about one or both.

I think the issue is yours in terms of how your are interpreting things. I read no tone, malice or for that matter any negativity.

Agreed. We get the exact same question daily and discuss thermal / acoustic.

Im actually right where you are in your building. Next weekend, I start framing and insulating.

Now, consider that I am in the great white north of Canada, so your insulation needs may be a bit different.

For my exterior walls, we are doing 1.5" of rigid XPS insulation (giving an R7.5 value) caulked/glued right against the foundation walls. Tape up all seams and spray foam around the edges.

Then, leave a half inch to one inch gap then building 2x4 walls, 24" off center. Walls will be built a half inch short and attached to joists with DC-04 clips.

From there, Im taking Roxul insulation to fill the cavities. Roxul is a basalt based insulation that really looks like someone sheared a sheep and made insulation out of it. In my personal opinion, Roxul is better than the pink stuff. Roxul is mold / moisture / fire resistant and is much more dense than the pink stuff, thus giving it better (although, not tons) 'sound resistance. All that, and it gives an R14 value).

Again, this is what I am doing and I personally feel is a good way to go. Others can chime in and let me know if I went wrong anywhere though.

Good luck with your build man. I'll be keeping in touch with this thread.

O.K., fair enough (although I still would be really surprised if the OP came to the AVS forum for advice on thermal issues ). I will acquiesce to those of you who know Dennis certainly better than I. I guess it's because I had just come from another thread where I thought he had been somewhat harsh in his debate with another poster (again, my interpretation).

I also didn't mean to hijack this thread. My apologies.

Ghost, that sounds like a great plan. Know, however that the mineral wool won't perform better acoustically in the cavities. Fiberglass, mineral wool, cellulose... they're all light and fluffy and that's what we want. Pick your poision.

Light and fluffy? Roxul? Really?

Wow, I hadnt realized. The only time I have "felt" it was through a hole in a package and it feels pretty damn dense. Yes, its all compacted to fit in the packaging but still, it feels pretty thick and dense.

Either way, its still a better option in my eyes given the resistance properties to mold and mildew. I just took out a bunch of pink stuff that was a bit moldy (of course, the basement wasnt done AT ALL properly when it was built .. SOOO half assed. Ugh).

Perfectly good reason for using it. Itchy, mold, fibers are all reasons to consider alternatives to fiberglass.

No, I don't know what he was after nor if his priority was thermal or acoustic. The answer is different in each case. This is particularily true in climates which tend to either a hot or cold extreme (or high humidity). I wouldn't want someone freezing their behind off while basking in acoustic bliss.

Ohhhhhhhh the itchy thing too. Forgot about that.

Just taking out the 35 year old existing insulation, I was dying. I had jeans on, taped up at the bottom around my shoes. A long sleeve turtle neck. Gloves taped shut on the sleeves. Then the 'hood' to my wind breaker with a 'gas mask' style mask over top.

May seem like overkill but I was STILL freaking itchy in some spots. Although, my wife mentioned the possibility that it was all in my head.

As I scratched my groin in front of her, I told her she was crazy.

She rolled her eyes at me

Korkster, this is a construction forum, you want politeness, go to a gardening forum. Around here we use duct tape for band-aids. One thing I've learned in my stay in this forum is there are a good number of very experienced people who have an edge to there approach of offering advice. Frankly I wouldn't have it any other way. Had the OP done a simple thread search on "insulation" there would be at least 50 threads in the last 12 months on this topic.

Hey Big,
Take it from somone who's actually done that with duct tape, among other available materials (paper from used cement bags comes readily to mind), I can be as "edgy" as anyone. I've been around construction sites since I was five years old tagging along with my father. And that was more years ago than I care to remember. And I've probably breathed in more fiberglass particles over the years than is in anybody's HT, before the days of dust masks. But always for thermal reasons, so reading about the acoustics of it has been interesting to follow.

By the way, have you ever gotten between anybody arguing over gardening philosophy? But again, we digress. Enough of this idle chit-chat.

Sound for sound isolation or room sound treatment?

You wouldn't use normal r-13/r-19 for sound treatments. Generally OC703 is used for in room treatments. Yes, it's still fiberglass, but the acoustic characteristics are very different.

One thing that hasn't been mentioned here yet, but is in other threads that you may want to look into as well as other construction related sites, are issues related to trapping moisture. Although you didn't mention it in your original post, I'm gathering by this that you're looking to do this in a basement? If you will be framing and insulating along your exterior basement walls, you need to be careful about trapping moisture which will result in mold and premature wood rot and masonary deterioration. Especially if your walls are all below grade.

This is the case even if you have what you would consider a dry basement. Condensation resulting from temperature change will be enough to make a mess of things. There are many schools of thought on how to prevent this including putting plastic between the framing and the drywall, putting plastic between the framing and the exterior wall, etc.

There are a couple of companies that have recently come out with insulation that is wrapped in plastic (R-13) to keep moisture out of the insulation. This can still trap moisture against the exterior wall however, unless you leave enough space for air to circulate. In fact, I am finishing my entire basement, and other than the small area of exterior wall that is within the theater room, I am not going to insulate the framed walls along the rest of the basement. I will just be putting drywall against the studs. And my framing is about 3/4" off of the concrete block wall. I may be in the minority on this one (and I probably am), but because my basement is completely below grade, I don't believe that I will gain that much more thermal protection than the ground surrounding my basement already provides. I am however, using R-30 insulation in my ceiling. As you know heat rises. That makes more of a difference than what's in the walls if they are below grade as far as thermal retention, IMHO.

You would not want hollow wall cavities for acoustic purposes however, so as I mentioned, I did insulate the walls aound the HT part of the basement, but they are interior framing for the most part. You just don't want to trap moisture in your walls if at all possible.

I found this information:

For most of the US, it seems the government recommends R10 on interior parameter walls of basements. A 2" foam board should do the trick. Best part is, you don't have to worry about it if it gets wet.

http://www.energysavers.gov/your_hom.../mytopic=11470

Nice link DG. Thanks for digging that up.

I wanted to add my two cents worth here -- but please understand I know NOTHING about sound isolation.

However, in our house, we did spray-in foam insulation (the kind that expands to fill the whole wall cavity -- I think that's the "open cell" kind). In any case, I just wanted to say that this is the most soundproof house I've ever been in. This was not our goal; our goal was superior insulation. However, that insulation really made for a much quieter house, particularly with the higher-pitched sounds (a jet roaring overhead is still audible, though muffled). Anyway, it seems to be much more soundproof than blown-in cellulose or fiberglass, and also a much better insulator (no drafts/air seepage through the walls).

Just my two cents, not sure if it helps anything...

Steve

Hi Steve,

Glad that worked out for you. Foam is tight and doesn't settle. I wish I had done it myself a few years back. Excellent thermal product. And the open cell is definately better acoustically than the closed cell.

For the sake of the large lurking audience out there, I'm compelled to respectfully point out that fiberglass, cellulose and mineral fiber all perform better acoustically if properly applied.

Super-insulated wall? Probably can't beat foam. For sound isolation, the more open and fluffy fiberous materials perform better.

Thanks-

Ted -- I appreciate your delicate approach to telling me "you are full of crap!" After reading all the stuff about "gardening forums" and "using duct tape for band aids," I figured I'd get skewered sooner or later for posting that, but instead you took it easy on the newbie!

Seriously, though, for whatever reason, this house is much more soundproof than any other I've lived in. It is also sealed much better, both due to the foam and other steps which were taken to make the home airtight. However, you are certainly an expert and I am not, so I do not doubt at all your statements about the other materials being better, acoustically. Perhaps other things contribute to this house being more soundproof than others I've lived in.

Steve