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Help / Comments - New Construction - Sort of...

Thanks for taking the time to read this if you are... It is a bit bittersweet for me, but the wife and I have put an offer in on a new home and it has been accepted. It is a bit sad after years of hard work into our current home, however situations with her business really dictate we move and build custom.

Now with the sweet of the bittersweet... The "better half" has also allowed me to use the "bonus room" as my dedicated listening room. It measures roughly 15'8" x 21'9" with a ceiling height of 9'. I have made some "minor" requests to the builder at this time. There is to be a "coffered ceiling" which consists of 6" wide by 8" deep beams... square pattern to consist of nine roughly 5'x7' rectangles. I am hoping this will help with diffusion. I have also requested the entire room be hung with double layers of sheetrock. The room is located on the second floor. Also to have 5 dedicated 20 amp lines ran to the room. On the short wall (behind my listening position) is the "chute" for the chimney from the greatroom below. This is approx 18" deep by 3 feet wide. I have made arrangements for cabinets (waist high) and bookshelves to the ceiling (for vinyl) to flank either side of the chimney chute. Only other option at this point was a solid door as well. I am planning on providing the cryo'd romex and duplex' and plan to have the breakers all on the same leg at the top of the box...

All else is yet to be determined. I have a wife that does not want *any* type of "tacky" sonic correction stuff anywhere... the best I have gotten so far is my Eighth Nerve room pack up...

So any suggestions, must do's... let me know. I am not certain I want double drywall, but was told that the stiffer the wall, the better the bass, and livlier the room, as well as help to isolate the sound.

At this point, we just signed the contract this evening, thus all *could be* changed... however budget is about zip, zero, zilch, nada, you get the idea... thus I worked the above into the room with the builder at this point. However, they estimate it will be 6 to 7 months until closing so if there ARE any "MUST DO" suggestions (afraid there will be many...) I do have time to react.

All help is greatly appreciated. My system link has all my gear, minus my TT that is on the way... Nottingham Spacedeck with Ace Space Arm, ZYX Airy3-S-SB with the Whest phono stage...
audiofankj
audiofankj OP
373 posts
 
Thanks again Jim. I am not fluent in builder/construction terminology, thus I am assuming if I ask the contractor to put the I joists on a 16" center, that is the amount of spacing between the I joists? The house in which I was measuring was not mine, just the same floorplan so I am unaware of what flooring they will be finishing in that room. However, as I am going with carpet you say to request a minimum of 3/4" subfloor? Even though this will most likely be a "temporary" listening room, it will still be five or six years, so I would have no problem with the double drywall of the walls - IF it will help at all sonically. We will most likely turn it into a small home theater room that doubles as a family room.

Thanks again!
tburn
35 posts
 
Hello Kirk - I concur w/ Jim - I simply wouldn't accept any subflooring (plywood) less than 3/4", and I would further stipulate 1/4" (preferrably 3/8") underlayment before laying carpet. I will simply state - a finished floor thickness of only 5/8" inch would be a joke! And I also agree, since apparently the subfloor will not be all that beefed up, to specify 16" on centers for the I-joists. To check this, find the midpoint of the top flange of any joist (width/2) and place a mark - then do the same on the neighboring joist. Measure the distance between these two marks - that will tell you the on center (o.c.) spacing of the I-joists. Jim was also correct to recommend solid blocking between the joists. I did a quick read about wood I-joists on the net, and from what I gathered, they will still exhibit flexing, but this can be reduced with blocking. A lot of this depends on your builder - is he a hands on carpenter, leading the crew, or does he drive around to his sites all day, in a new pickup and carrying a briefcase. IMHO, the latter variety will cut every corner imaginable to add to his bottom line. 'Nuf said.
And to reiterate one last time, insist on construction glue being applied on top of the joist before the plywood is layed. Unless you are present during this phase, there is no way of knowing if this was indeed done, other than to find the empty "tubes" laying in the trash pile later. You need to tell the builder you expect to see these. Quite simply, there is either the right way or wrong way to frame a house. Again, best of luck ... Tom
jea48
4,453 posts
 
16" center to center. Do not let the builder talk you out of it. If you can go into one of the houses being built just go to the middle of one of the rooms. Bounce up and down just a little, you will know what I mean. Even heavy walking across the floor you will fell the spring in the floor. If the joists are indeed 19.2" center to center you will want to change the specs on the first floor and the second floor. Now, you know why the builder is installing the joists the max allowed 19.2" center to center. The builder is cutting his cost one "I" joist for every 8' of run. Here is your problem as I see it now. You have already signed the contracts. If you decide you want to change the joist spacing to 16" CC The builder has the pricing leverage. Use your head when you talk to him.
audiofankj OP
373 posts
 
Thanks much Tom & Jim - Much appreciated. I was able to drive over again today and re-measure. It does appear the current spacing of the I joists to be 19.2" center to center, I didn't measure this - don't know how I forgot but did measure just about all else. It is as follows, and hopefully not as bad as initially thought:

The I joists are a height of 14" exactly - that is including the "2x4" on each end of the I joist. They are being installed width wise of the room, approx just under 16 feet.

I measured the plywood subfloor to be 3/4" thick with the tape measure. However, stamped onto the subfloor was ' T&G Engineered - 23/32" ' I am assuming this means they are tongue and groove pieces of plywood? Full pieces were 47.5" wide by 8 feet long. They were laid in a staggered pattern as well.

Let me know if this will be sufficient for a subfloor, with the construction glue & 16" on center? Or should I also ask for blocking?

I did have my wife with me, and had her stand in the middle of the room and jump up and down a good foot or so in the air, and I was about a foot from her, there was approx 1-2" of flex noticable in the floor. However with her walking I could feel it, but not notice any bounce... again this may be different with a needle on the record.

Also, this house is just in the beginning stages... frame just went up, plumbing is going in now, and shingles being put on... as the windows were going in today if any of that is of relevance.

Thanks again. Any other thoughts on what to request of the builder before I talk to him? As of now:

- I joists on 16" centers

- minimum of the 23/32" T&G engineered subfloor (if acceptable to you guys?) construction glued to the I joists

Do I ask for the blocking? Or at this time, make certain he is aware I want the primary layer of drywall taped and mudded as normal, then the second layer laid on top and finished...
jea48
4,453 posts
 
23/32" that is the thickness, nominal 3/4". Like a 2X4, if you measure it, it is not really a 2X4. The solid bridging in the sound room would be nice. What it will do, no matter where you are walking it will also transfer the load to the joists on either side of the one the weight is on. Did you notice if the T&G was screwed down. In my city it is. Glued and screwed.
Not sure why you want the first layer of rock mud and taped. If you are not going to use wall damping pads between the two layers of rock just make sure the sheet rocker uses a lot of wall adhesive between the two staggered layers of rock. Again glued and screwed. Not nailed. Bass will pop nails over time. Infact I hope the rockers in your area, screw all the rock in the house, not nail it. Also make sure the electrician knows this room will be double rocked. So he can set his rough-in boxes for the correct depth. By the way, any idea the distance your electrical audio oulets will be from the main electrical panel? Those dedicated circuits...
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