# automatic door sill with carpet?



## memarcus (Jan 28, 2010)

Looking at door products to soundproof the door..... I was wondering if anyone had an automatic door sweep over carpet. Most pics online show them in pro studios and such where they have vinyl tile or some hard surface to seal against.

My theater will have carpet inside and transition to some other type of carpet in the doorway. Is it neccessary to have the big door sill plate as well or will the typical automatic door sweep seal effectively against carpet?

Will be installing a solid slab 1-3/4" door with some seal products at the edge and planned a sweep for the door, just didn't know about the threshold. I suppose it would make a handy cover for the carpet transition, but was wondering if it's absolutely necessary or not as I'm not real happy with how most I've seen look......


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## bpape (Sep 14, 2006)

I would just use a nice piece of wood as the transition to allow it to seal better.


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## memarcus (Jan 28, 2010)

That's an idea. Just not sure on the minor details. I'm in a basement on a slab so I suppose I'd have to rabbet the sill plate on either side to allow the carpet to run under and then attach it to the concrete maybe with glue or plugged screws. Seems like some construction adhesive would do the trick.

another question though. In the wall construction I have interior walls separated by a 1/2 gap all around, a room in a room type. I've went with double drywall (and insulation) but since the walls can move independantly of the other walls I didn't do resilient channel or greenglue. According to the architects at work this should provide and STC rating in the high 50's. The ceiling is fully independant of the structure above with about a 12" gap above the ceiling joists and bottom of the floor joists above. All well insulated.

It seems from the literature from a couple door hardware manufacturers, my door selection (1-3/4" solid with sweep and seals, plus sill of some sort) is by far the weak point. Since I have a 8" thick wall I could do a second door on the inside and there'd be an airlock but only 4 or 5" thick. Does anyone have any guess as to what reduction I'd get with two soundproofed doors back to back or would I be wasting my time since I forwent the GG and channel on the walls ceiling? I assume a double door setup would still be chaeper than a true STC 56 door that's 2-3/4" thick. Anyone know a ballpark price of those?


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## bpape (Sep 14, 2006)

If you can tolerate the 2 doors, that will definitely beef up the weak point in the isolation. If you want to do more research, they're normally referred to as communicating doors.

Bryan


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## Tooley (Jan 2, 2011)

You could also order a sound proof door here in Canada you can order them from Lowes a 32"x80" is $169


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## memarcus (Jan 28, 2010)

Huh. I'll have ot check the local Lowes for a significantly thick door. I never would have guessed they are that cheap. however most of the STC 56 doors have special hinges since they weigh a bunch and I'm sure a handle and lockset wouldn't be cheap. 

Seems to me a comunicating door setup with seals all around would do better than the single STC-56 door? any opinions? the gap between would only be about 4". I could possibly make and accoustic panel to fill the space and attach it to the inside door.

I have to check space constraints though, and inward swinging door will but right up against my main left speaker and might impede screen size if I have to move the speaker inward to accomodate since I'm not using an AT screen.


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## HopefulFred (Jan 20, 2011)

Sealed communicating doors will be the best isolation short of custom doors. I don't want to give up the space for the extra door in my home theater, so I'm going with a single door, like what you described in your first post. I'm also considering using four bearing hinges so that I can add mass via damped (green glue) layers of MDF to is afterwards. For truly engineered doors that can outperform communicating doors, I'd expect to pay upwards of $1500 (the only pricing i've seen is double that).


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## memarcus (Jan 28, 2010)

that's sort of what I thought. These things are beefy doors I can't imagine they would be cheap. On one website I saw a purpose built door jack for installation, so if there's specialty equipment available for installation they simply can't be trivial in cost.

I think what I'll do is hang on 1-3/4" solid MDF slab door with seals and sill, see how it works and fits our needs first. If further reduction is needed I'll add a second door. I think the door will stay open 90% of the time anyway.


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