Room Isolation - door through

[John Sayers]

Voxboy - go with solid core wooden doors in a sturdy door Jamb.

Stuart and Ro - would guys care to enlighten us on your experience with steel doors for isolation?

[Soundman2020]

Stuart and Ro - would guys care to enlighten us on your experience with steel doors for isolation?

I looked into this a while back, when I was trying to figure out what kind of doors would be best for my room, and I came across several companies that make steel acoustic doors. Some even make industrial-grade steel acoustic doors, for factories and plants.

I was really interested in the idea of steel doors when I saw that some of those guys offer STC ratings up in the 50’s and even 60’s range, but I totally gave up on the idea when I saw the prices Even a low-STC-rated steel acoustic door is going to cost you a small fortune. Add up the cost of four or six doors, which is what I would need, and it eats up my complete budget for the entire studio! So I gave up on that idea, and I’m just going with Rod’s door designs for some doors, and probably a pair of your sliding glass designs in one other place. Steel is a great concept for doors, but way out of my price range.

Anyway, here are some of the links that I had saved for those steel acoustic doors, FWIW:

http://www.alibaba.com/product-free/103 ... DOORS.html
http://www.cmsacoustics.co.uk/c-acousti ... l_door.htm
http://www.industrialacoustics.com/uk/d ... _doors.asp
http://www.oeler.com/highperf_doors_windows.html
http://www.acousticalsolutions.com/prod ... /doors.asp
http://www.rivett.com/fleming.html
http://www.power-technology.com/contrac ... tflo2.html
http://www.tradeindia.com/selloffer/170 ... Doors.html

[voxboy]

Steel is actually pretty good at isolating, if it is reasonably thick. Steel is roughly three to four times more dense than concrete, and about eight to ten times as dense as drywall. So if you get a door with 6 mm thick steel (about 1/4") then that's already roughly the same mass as three sheets of 5/8" drywall. But don't get a thin steel door: it will probably resonate too easily.

How thick is the steel on those doors you saw?

Took another trip to Home Depot after a Tee Ball game to do some recon. The steel door that I saw was fiber glass filled 26 gauge steel. It's still pretty heavy, but the 26 ga steel has me concerned now. It's no where near 6mm steel. What I do like about it is that the door jamb is solid and already beefed up. Plus it's readily available at Home Depot. Price of the door is $116. The price of the solid core door (used door with fabricated jamb) I wanted to order with the four heavy duty hinges wold be about $100. Given the prices of both door options, what woudl you all do?

[John Sayers]

Thanks for the links Stuart. excellent references.

Voxboy - tap the steel door - I bet it rings.

[Soundman2020]

That steel sounds way too thin, and the price sounds way too low for the kind of steel door you need. The ones I priced when I did this exercise before started at around US$ 1,000 or so (each door!), and go up to something like US$ 4,000, so I don't think you'll be getting anything like what you need for US$ 116.

The steel door that I saw was fiber glass filled 26 gauge steel.

"Filled"? That makes me think it is hollow inside! Not what you want. I thought you were talking about the kind of sheet steel doors that I've seen here in Chile.

Given the prices of both door options, what woudl you all do?

I'd go with the solid core wood, I think. Like John said, I bet that kind of light weight steel will ring like a bell if you tap it. That's what I meant by my comment about resonance. You don't want your door to join in with the band, and sing some of its own harmonies for you! You might be able to beef up the steel door somehow, but I wouldn't have a clue how you would go about that, or how successful you would be, but a solid core wood door is a tried and trusted method, and there are known ways of making that work well.

By the way, do you have Rod's book, Voxboy? If so, then look on pages 92 - 98 for details about how to build your own door, based on a solid-core wood door. You basically just add mass to it, and seals around the edges. It works out much cheaper than a manufactured acoustic door.

- Stuart -

[Ro]

Years ago we installed a thick steel door on a rehearsal room, it's pretty heavy. It worked like a charm, there was only some leaking on the perimeters since we didn't seal it of. (later we did)
The door was rescued from from an old building.

Recently I helped a friend with converting an old shed into a rehearsal room. It had a "semi" steel door in there already. Let's see if I can dig up some pix. It's absolutely soundproof. The door was a combo off steel and wood. 17cm thick 0_o

edit: here's an old pic of that door. unsealed yet. the room belongs to a friend. it's a work in progress

[John Sayers]

thanks Ro. can you get the pics, that would be cool?

[Ro]

just uploaded on old (before) pic. I'll ask for an update

[voxboy]

Years ago we installed a thick steel door on a rehearsal room, it's pretty heavy. It worked like a charm, there was only some leaking on the perimeters since we didn't seal it of. (later we did)
The door was rescued from from an old building.

Recently I helped a friend with converting an old shed into a rehearsal room. It had a "semi" steel door in there already. Let's see if I can dig up some pix. It's absolutely soundproof. The door was a combo off steel and wood. 17cm thick 0_o

edit: here's an old pic of that door. unsealed yet. the room belongs to a friend. it's a work in progress

Jeeezzzzz.......Talk about beefed up....that's got to be from a meat locker or something.

After looking at the cheaper steel door at HD again. I'm thinking I'll use the solid wood door. The door was filled with fiberglass and was pretty dead sounding when I tapped it. BUT, I'm not quite convinced it's going to do the job. Since the steel itself is only about 1 mil total. 26 ga steel is about .017 in. and 1mm is about .03 in. The doors are not hollow, but filled with rigid fiberglass. I'd still want to add more mass to it, so why not just use the solid wood door in the first place.

BTW, I do have Rod's book, and refer to it constantly. Cover is getting a little dog-eared, but not to worry.

[Ro]

Yup, beaflocker door indeed

Forget about that flimpsy "steel" door than and go with a good old trusty solid wood core. Beef it up as needed.

[voxboy]

You all have been a great sounding board. Thanks for the input and the help. Ordered there doors this morning, $90 a pop, 1" jamp, solid core, 36" x 80". Will take pics of the install and the extra mass that I add. .

[lilith_envy]

Steel frame/ wooden door.

That way you can add all the (cheap)mass you want to the solid core door without having to worry about it's weight. Within reason.
Most of the hinges are welded or screwed directly to the frame.

that would save a bit of $$
Any steel manufacturer will have steel doors you can buy of the shelf.

[Zenon Marko]

Actually, Rod suggests that it is better to build one single solid frame, all the way through, all the way around, and hang both doors on that one frame. So yes, the frame in that case actually will couple both sides of the wall.

IIRC, the main reason Rod says he does that is for safety: hanging a pair of huge, massive doors on a flimsy single frame each is not a good idea. Better to have them both hung on a shared very solid frame, which goes right through the wall to both sides for strength. Rod says that the slight amount of coupling / flanking that you will get with this method is negligible in the overall scheme of things, which is why it is so important to make sure that there is absolutely no coupling elsewhere: since this door frame will be the weak point, you don't want any more of them! You build the rest perfectly so that you can do what has to be done at the door frame for safety.

It's clear how you should do it, on page 96 of his book: one single large frame all around, with both doors hanging from it.


- Stuart -

I'm very interested in this...Realizing it's an old thread. Do you, Stuart (and others here), still recommend this through-jamb approach?

Rod Gervais indeed shows a through-jamb for both the single-door and double-door assemblies for 2-leaf (double-wall) systems.
Mr. Gervais states in the beginning of the section that "I’ll let you know right now that this is one place I don’t worry about maintaining the separation of wall assemblies with the frames, even when using totally separated assemblies."

(In 2nd edition of the book, those assemblies are illustrated on pages 106-107).

There seem to be several potential isolation problems here:

1. The through-jamb itself
The through-jamb itself obviously is a direct flanking path, since it's a single hard element cutting through from one room to the other, although, Rod states therein the resulting isolation compromise is negligible.
"[A] through jamb does not effectively lessen the total isolation value of a wall assembly to any great degree. So don’t worry about any miniscule amount of isolation you may lose. Just build the frame straight through the cavity." (2nd edition, p104-105)

2. The coupling of the walls via the through-jamb
In the illustrations, there is some apparent attempt at keeping the walls de-coupled via the layer of compressed rockwool, but that that attempt seems to be again somewhat-short-circuited, via the flanking path through the jamb and 1x4 wood casing shown. Does the compressed rockwool really benefit TL? If so, could neoprene rubber serve just as well or better than rockwool?

3. The connection of jamb to walls
It's also not clear how the door jamb is attached to the walls (and ceiling). Is it screwed through to the two walls, which screws would provide another hard flanking path?

Thank you to any and all for input on this.

[mrtomcat]

I would also like to dive into this thread some more since I am exactly at this point to get the doors...
Here is a steel door at home depot that weights more than the usual solid core wood doors (my assumption being mass = weight...) that I was going to get until I found this post... now I am not sure again.
can you take a look please and provide some suggestions?

https://www.homedepot.com/p/Masonite-32 ... /100095265

I figure I can do some more beefing up with this one as well.

[BrandonClarke]

@Soundman2020
You can also include https://www.iacacoustics.global/acoustic-doors/ acoustic doors made by IAC Acoustics in the list. These are the best acoustic products in the world, manufactured by the experienced acoustic engineers and consultants.