Building a "Quiet" Wall, need some advice please.

[RICK FITZPATRICK]

If I do rip the 1/2" off the door, I have read that putting masking tap on both sides and ripping through it will minimize splintering. Does that sound about right?

Yes to an extent. It depends on how many teeth your blade has and if they are carbide. 40 or 60 tooth crosscut carbide, or a good 60 tooth steel will work. Carbides are cheap now though. I bought a 60 tooth Black and Decker "Pirana" carbide crosscut blade at Wall Fart for $25. Not great, but good enough for this project. I use cheap blades for cutting old stuff with possible nails etc. I use a lot of recycled wood. Anyway, it will work for the hardwoods too. Do you have a Skill saw? You know, the hand held electric circular saw? How about a router?
Ok, does your door already have a hole for the latchset? If not, we will have to deal with that too. Later.

This will be my first door-mounting of any kind. You are correct in thinking that I am a bit leery of working with the chisel to chisel out the hinges on the jamb and the door. It really seems like a LOT of work to do it right, and any insight is GREATLY appreciated.

Don't worry. I'll walk you through EACH STEP. The trick to this stuff is knowing what the goal is of each step, how it relates to the next step, and sequencing things so you don't get ahead of yourself. Murphy is always at your side The trick is to OUTTHINK him! Ha! I'll be posting some CAD layouts showing how to do this stuff at each step. But it takes me a little time to draw it. Also I have a digital camera and I'll take some pics of a similar setup to illustrate things. Don't worry, it wil be ok. By the time you finish, you will have learned HOW to hang a door. Its a good one to have under your belt. Makes other things easy, cause you learn new tricks to apply to other projects.

Ok, I'll be back later with some instructions. Got to go build a roof to this doghouse Some people have money to burn. Never ceases to amaze me.

fitZ

 

[Ibrow]

Got to go build a roof to this doghouse Some people have money to burn.

It's not YOUR doghouse? LOL! I guess some folks do have money to burn.

I have a skil saw, a couple actually. The door I am looking at does not have the hole cut yet for the knob. I don't have a router, as I really don't know what the hell they do and haven't (I think) come across a use for one yet. LOL! I have a small mitre saw that handles 4x6's at 90*. I have a belt sander, jigsaw, compressor and finishing nailer(if that matters ). That about sums it up.

I have installed a bunch of small sliding basement windows and done the finishing on them in my house. I haven't ever done anything as elaborate as a door, or for that matter, built a wall. Until now.

If it helps at all, because of many factors, the door is being built "flush" with the outside wall. i.e. outside the bedroom opening into the livingroom. The doorknob will be on the right.

Looking at the SAE page, a wall like mine with double sheetrock(if done correctly of course) is an STC of 54. With single sheetrock it is 48. Are those 6 db's really that big a deal? My pal was telling me to single-sheetrock(5/8") as there won't be much difference, if any with the second layer. If I remember correctly, sound doubles every 3 db's correct? But, with STC, you just subtract the STC value from the noise source DB's, right? So, theoretically, if a TV were on in the other room, at say, 80 db's, and came through the STC 54 wall, that would knock it down to a 26db whisper, or basically, very quiet. On the other hand, with the 48 DB wall, the source would be down to 32 db's, which, is also basically a whisper, right? But, if I have this right, that 32 db whisper will be 4X as loud as the 26 db? Not that a whisper is loud. I guess, what I am asking, is why am I double-sheetrocking again? Do I have any of this right? LOL!

Thanks so very much for the help!

 

[RICK FITZPATRICK]

This will explain more than I EVER could.
fitZ
http://www.domesticsoundproofing.co.uk/tloss.htm

 

[RICK FITZPATRICK]

It's not YOUR doghouse? LOL! I guess some folks do have money to burn.

Yea, like $2k on a doghouse and a 5'x8' deck thats 8" high, some gravel and another $600 for the fence. The doghouse matches the design and detailing of the owners house. Took a week to build the dog mansion.....er house. Hahahaha.
Anyway, tonight I'm drawing the door jamb/hinge layouts for you. I'll post them in the morning. Also some instructions too.
Ok, about the STC thing. First off, this stands for Soundt Transmission Class, and its a rating given to TESTED assemblys. However, you can't go by that alone. This rating is ONLY as good as your WEAKEST link. Which you have FIVE. Your existing floor, 2 walls, ceiling, and the door. Since your wall is simply a partition added to an existing space, the floor, walls and ceiling are continuous membranes which may allow a structural flanking path. No way around it. That is why I suggested building the EASIEST scenario, as the others would STILL have the weakest links too. That IS a problem that only will raise its head once your wall is compleated. The best thing I can advise is to not place speakers against a wall, or a HEADBOARD or a TV touching a wall. Things that will transmit through the structure because they are touching. Airborn noise will vibrate the existing walls etc, however there is NOTHING YOU CAN DO ABOUT IT!. The new wall is to keep direct airborn noise from vibrating this membrane on the opposite face(to an extent), but is only as good as your craftsmanship. If you "couple" one face to the other in any way, other than the plates, you will negate the purpose of the staggered studs. That is why I showed you the door jamb with a "floating" trim on one face. Thats to keep the door from vibrating the jamb to the opposite face through the jamb. Being solid, the door itself WILL resonate at a certain frequency, and will transmit at a certain db threshold, but who REALLY knows what that is. I can tell you this though. If this were for a studio, the door would be the weak link, and normally, would be a set of DOUBLE DOORS in a DOUBLE Wall. But that would have been rediculous in this case because of the EXISTING weak links. So, I hope this doesn't discourage you, but under the circumstances, you are doing what I feel is the best course of action.
I do know this. Your friend was wrong about this wall and double sheetrock on each face. Each doubling of mass reduces transmission by 6db(I believe).
Remember, I am NO expert, but I KNOW this wall will be MUCH BETTER than a
standard residential wall assembly. Even an expert couldn't predict the transmission outcome BECAUSE of the existing weak links. Ok, on to the door. I'll be back tomorrow morning. Later.
fitZ

 

[RICK FITZPATRICK]

Hello Ibrow. As usual, not much time this morning but I did manage to write out a couple of paragraphs to start. But I ran into some questions. I sent you an HR email last night. Did you get it. Look at your inbox. Now I have one question to ask before I can continue. That is the "HAND" of your door. Take a look at the pic. "Hand is determined by standing on the "exterior(hinge knuckle exposed) side of the door facing it. Like the street side of an exterior door, although an interior door is the same, as far as the knuckle is concerned. Anyway let me know.
Ok, a couple of other things too. A solid core door that has particle board as its core, will have a solid wood perimeter USUALLY. The width of these boards cannot be seen, because they are behind the veneer. The point is, they may only be an INCH wide. Therefore, to keep a consistant width on these, I suggest
when you cut the WIDTH of the door by 1/2", you cut 1/4" off EACH edge.
As to the height, I would probably cut off the bottom but ONLY AFTER your jamb has been installed. There are LOTS of things to sequence here so don't get ahead of yourself.
The other thing I need is your ROUGH opening dimensions, and an answer to the question on the email. When I know these, I will proceed to post some instructions and pics. OK? Later.
fitZ

 

[knightfly]

Rick, if you haven't already check the links I posted near the beginning;(not sure ANYONE has yet from the lack of comments) may save you some 'splaining time... Steve

 

[RICK FITZPATRICK]

Hey Steve, thanks buddy. I need ALL the help I can get. I'm overwhelmed with a doghouse. (almost done) I didn't even check those when you posted em. I will now. Ok, back on my head. later buddy.


Hey Ibrow, heres a couple of more. They might be helpful if I miss some things that you don't know and I assume you do. The don't cover ALL the tricks, but at least some important stuff.
http://searcht.netscape.com/ns/boom...diyworld.co.uk/fitting_external_doors_p5.html
http://searcht.netscape.com/ns/boom...taunton.com/finehomebuilding/pages/h00122.asp
fitZ

 

[seismetr0n]

Ive also read that using blown in cellulose will greatly reduce the stc of your wall... my house is full of it and with 6 inches you can barely hear the band playing from outside, with standard framed wall. Also, might want to use different thickness' of drywall on each side to reduce sympathetic vibrations

 

[knightfly]

Good call, quake-man :=) done correctly, blown in cellulose does have better acoustic properties than almost any other insulation. 6" walls doesn't hurt the m-a-m equation either.

Different thicknesses of drywall, though, only affects the high mids - typically around 2-3kHz, where drywall's coincidence frequency lies.

In most cases, the extra mass obtained by just using more layers of 5/8 drywall will give better APPARENT isolation, especially for music, because it makes more difference in the BASS region.

The extra layers also improve things at the upper, coincidence, range not because they get rid of that "dip" in isolation, but because they just improve the entire curve due to mass law.

Not to nitpick, but "greatly reduce the stc of your wall" means to make it WORSE... Steve

 

[seismetr0n]

thanks for the clarifacation knightfly... hey it wasnt bad for me first post eh