Room Isolation - door through

[voxboy]

I have a question about how to maintain separation between two isolated walls where a two opposing doors need to be installed. How do you maintain isolation when the treadplate and transom, is shared between both doors/wall, will provide a path for vibration. Any advice or even a construction detail?

[Sandersd]

I have a question about how to maintain separation between two isolated walls where a two opposing doors need to be installed. How do you maintain isolation when the treadplate and transom, is shared between both doors/wall, will provide a path for vibration. Any advice or even a construction detail?

Don't connect the treadplate and transom is the advice given in most construction guides.

[voxboy]

I have a question about how to maintain separation between two isolated walls where a two opposing doors need to be installed. How do you maintain isolation when the treadplate and transom, is shared between both doors/wall, will provide a path for vibration. Any advice or even a construction detail?

Don't connect the treadplate and transom is the advice given in most construction guides.

That's what I am getting at. Would you construct the door frame in this case, similar to the way you would for an Isolated Frame double-glazed window. I'm basically referring to the construction details Figure 5.2 & 5.3 in Rod's book, Home Recording Studio : Build it like the Pros. I was going to post scanned copies of those figures, but I also want to ask the moderators, as well as Rod Gervais himself, if it would be ok to do so......before I did so. What say you all?

Also, if I am going the two door route, should I still use 5/4 stock for the door frame, or will regular 5/8" jamb stock suffice? Perhaps 1" lumber for a jamb? Suggestions?

I'm hoping that using that construction concept, in that I can still keep the doorway solid and sturdy, and maintain the max. amount of isolation. Input, help, comments..............thanks in advance for any of these!!!!!

regards,

Chris

[Sandersd]

Would you construct the door frame in this case, similar to the way you would for an Isolated Frame double-glazed window.

Yes, very similar. Post some pics or sketches so we can see what you're doing. BTW - "treadplate" and "transom"? Where are you from?

[Soundman2020]

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 -

[Ro]

Yes, with heavy doors you need solid frame constructions. Really.
I've seen "flimsy" frames on this board in several builds. Slamming and even just opening a door will weaken the frame more and more..

Building one solid frame... dunno. Rod says "sure". I say "hmmm". Building 2 solid frames would be a solution. Coupling them 2 frames would be your choice. It sure depends on the rest of your build.

[Sandersd]

You could build one solid frame and just not attach it to the inner wall (leave a 1/4" space, caulk it of course), or attach it using a decoupling/isolation bracket.

[voxboy]

Stuart, totally understand where you are coming from and that approach makes perfert sense. With the amount of mass that I'm adding, the transmission that is going to occur shouldn't be much since I've decoupled the room pretty much everywhere else.

BUT, I'm with Ro on the door frame itself. I'm ordering the doors today and I think I'm going to go with separate frames and just couple them once the frames are in stalled. Not much difference in the price, but I'm not sure which solution will be easier for installation.

As for the treadplate and transom.............I really should have just said the entire door frame would be shared, not just a shared treadplate and transom.

Thanks for the advice and perspective. Just the right amount of push to get me moving again confidently.

[Soundman2020]

I'm ordering the doors today and I think I'm going to go with separate frames and just couple them once the frames are in stalled. Not much difference in the price, but I'm not sure which solution will be easier for installation.

As long as they are really solid, really tough frames, then I don't see a problem doing it that way. In my case, I plan to double up on everything around the door framing, and add a few extra members here and there, for strength.

- Stuart -

[voxboy]

I'm ordering the doors today and I think I'm going to go with separate frames and just couple them once the frames are in stalled. Not much difference in the price, but I'm not sure which solution will be easier for installation.

As long as they are really solid, really tough frames, then I don't see a problem doing it that way. In my case, I plan to double up on everything around the door framing, and add a few extra members here and there, for strength.

- Stuart -

That is pretty much what I've done with rough framing. I have double studded around the entire doorway for both walls. It's pretty solid, so I'm not too worried about going with a 1" (3/4") door jamb. I'm ordering the doors with four heavy duty hinges a piece and 1" jamb.

[John Sayers]

Let's face it - if you intend to hang big heavy doors you are also dealing with big heavy walls.

[Soundman2020]

That is pretty much what I've done with rough framing. I have double studded around the entire doorway for both walls. It's pretty solid, so I'm not too worried about going with a 1" (3/4") door jamb. I'm ordering the doors with four heavy duty hinges a piece and 1" jamb.

Don't forget that you'll need some extra-long screws for the hinges, to go right through the jambs and deep into the underlying framing. They need to go deeeeeep....

- Stuart -

[voxboy]

Well, one trip to Home Depot this evening and I've run into another question. Steel Doors? Have any of you all used Steel Doors? What is your take on them vs. Wooden Doors?

[Soundman2020]

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?

[Ro]

Yeah, Peter Steel his doors do wonders

Steel is good, as Stu pointed out they are heavy. But how much buckaroons would such a door cost?