BritInVA Construction Thread - Page 2

Ashburnite here as well!

I just started a sperate thread w/ contruction pics yesterday.

I've had similar experiences with the Loudoun county offices: wanted a sketch on their form, quick, and generally helpful. I've called the office a few time with specific questions and they've been gernerally helpful as well.

The real test will come at inspection time... perhaps next week for me.

we had our final inspection yesterday (Loudoun County) and all passed: electrical; mechanical & framing. he looked at some of the Ht modifications, miles of wiring and wacky conduit and scratched his head but for the most part he was pretty easy going.

They did question my installation of a thermostatically controlled whisper vent/exhaust fan over my HT equipment rack. since the rack resides in the utility (furnace) room he was concerned about a direct vent to the outside. it was discussed for a while and decided it was OK. I'm not sure why it was an issue since many of the new homes here have fresh air vent into the furnance room. The homes are becoming so "tight" you need more fresh air for combustion.

good luck guys.

billmac

Billmac:

You say the rack resides in the utility room. His concern was probably that the exhaust fan could (if strong enough and the utility room has poor ventalation) suck the CO out of the water heater and the furnace vent stacks and create a kill zone.

If you ever go in the utility room and feel sleepy don't lay down.

Tom: I'm 50/50 for Saturday at this point. and You?

Jeff

Brit: Food for thought: Most people complain about their theaters getting too hot. not sure why you are trying so hard to keep it in.

Probably another wasted Saturday running errands instead of building, so I'm more like 99/1. Should have the wife in tow, if that gets you out of the house any easier!

Tom

Jeff,

I think you're right. I was talking with my HVAC guy before the inspection and he was suggesting we add enough fresh air vents to the utility room to alleviate that potential problem.

billmac

Hi,

Rovkville MD here. Not exactly a 9 iron away but definitely driving distance even with the notorious DC traffic.

I am planning to convert part of my unfinished basement to a HT and need a lot of help. The room will be 14 by 19. There are 2 weight bearing posts in the area but shouldn't be a show stopper. One is 1 foot from one of the long wall and 12 feet from the screen. The other one is 3 feet from the back wall (16 from the screen) and 6 feet from the same long wall. The ceiling is 8 3/4' concrete to joists. The room basically will have a stage, 2 3-seaters, a riser. Will have a seperate room/closet for the equipments. Here are the questions:

1- Speaker placement for 7.1 and 5.1
2- Soundproof insulation options, wall & ceiling
3- Wall finish options
4- screen size, ratio
5- seat placement
6- projector postion
7- concrete treatment (seal, dricore, ...etc)

I will stop at 7 for now but anything above and beyond are more than welcome. I don't mind spending extra 2,3 K (on top of, say, 5k, just the room, not the equipments) to make the room look better/sound/perform better but that's about all I can commit now.

I am a true HT novice and an okay DIYer. I would like to start framing the room in the next week or two and take all suggestions into consideration.

Thanks a lot.


Eric

Lookin real good!

A little off topic:

Does anyone have roughly 30 feet (4'x30') of Linacoustic?

Thanks and sorry for the interruption.

Brit -

I don't know what the codes are, but from some of the pictures I've seen, they can't be too hard how the lines are run.

Looking good so far! Tear down that fast must have been a back breaker!

Tom

Brit:

Codes:

If you go to HD and look at their "code check" series of spiral bound plastic coated books they have one for mechanical and it would give you some ideas about universal codes. Just read don't bother buying.

I do know there is a limitation on how close a return air supply vent can be to the furnace and I think it's 10 ft. If it's in another room it doesn't matter.

From your pictures it doesn't look like the air supply will be much of an issue. I would tie into the top of the duct inside that soffit and bring the flex duct between the joists to the outside perimeter of the room.

From my discussion with a HVAC guy, for basements in this area it's preferred to leave the supplies up high and the returns as close to the floor as possible. If you can put them at opposite ends/sides of the room that is recommended.

There are some ways to mitigate the sound coming/going via the duct work by choice of duct work. The flex sold at HD is not the best for sound control it has a plastic inner sleave. They make a version that has an inner sleave that is acoustically transparent and allows the sound to be absorbed by the insulation. I didn't use but it's available. I've seen it on some web page.

Also you are going to want to have some 90 degree bends.

You can also get in-line duct mufflers

You can also build a DIY serpentine box to contain sound

Brit

Just a head up.

Air volume in a HVAC is a lot different than Electricity more like water. You have to keep things in balance.

Fluid mechanics determines the volume of flow.

Think of the main supply trunk as an area of uniform constant pressure. the size of the holes (and to a lesser extent the resistance along the duct) determines the volume of air that will enter the duct. If you split an existing branch to feed an existing and a new vent you will cut the volume in half at each outlet.

It's better to tie your new room back to main trunk. Lets say the main trunk services 10 ducts. Adding 2 new will cut the volume at any one existing duct by 20% (swag). A lot better than 50%.

I was able to reach up betweent joists and tap onto the top of my main supply trunk (in your existing soffit)

If you can tap in at least one joist bay you could put more than one tap in that location and then move laterally inside a soffit in the theater. That is if you are building a soffit otherwise never mind. You could put an oversize tap and branch it in the theater as well.

I don't see why not. It goes horizontally at ceiling level for the rest of the house from you picture. It's horizontal in my house.

Some thing to be aware of. If you are like me I like my Subs. If you are concerned about the LFE noise going to the rest of the house I'd do a couple of things.

Keep the return vents away from the subs. Maybe somebody can model your room and tell you where along the front wall would be best.

Think about strategies that can tame the sound entering the return air system in the HT. Mufflers, Serpentine boxes, choice of duct material etc.


Just another thing to bounce off you. You are talking about supply in the rear and returns in the front. I've read that people are most comfortable the other way around. (cold draft on the back of the neck thing). Have you thought about orienting your theater the other way?

I didn't intend for you to jump that fast. You may want to post a new thread with the title.

"where to put return vents in stage to minimize sound leakage?"

That should bring out all the acoustical gurus.

Are you using wood paneling on all wall surfaces except the soffit?

On the soffit, how do you plan to attach the GoM to the drywall? Typically GoM is applied over firring frames, ideally over Linacoustic.

A couple of comments. Clarence is correct, you need to figure out how to staple the GOM to something in the corner. You can always cover it with crown, but you can't staple it to the drywall. My design was to include Linacoustic under the soffits, so I needed the furring there anyway. Turns out after talked to bpape, that I didn't need the Linacoustic, so my GOM covers 1" of empty space, although you'd never know it.

Also, you need an area to staple the GOM to on the other end (where the rope light is). I used 1x6s inside my trey to staple onto, but even so, it was sort of difficult to get the staple gun up there. You have a tight spot there for getting the staple gun in. It looks like the slanted side is pretty large. Mine is only about 6 inches. You might be able to go a little smaller and give yourself a little more room to play with. Also, that gives you more of an uplight on the corners of the ceiling. By having the rope light so close to the ceiling in a tight spot, you'll have less effect, but that may be the look you want.

Are you planning on building panels (ala Sandman) for the starfield or do you have access from above?

Bud