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Site-built back-to-back studio door pair, for high isolation.
A quick photo-sequence on how to build your own isolation doors for your studio, with windows in them, and still get good isolation.
This is a companion article to the site built window for high isolation, and uses a simple but very effective design that I have developed for such doors.
These photos come from a client in Australia, who teaches drums in his studio. His neighbor's front door is just a few meters away from the door to his studio, so he needed to get very good isolation. The door design I did for him is not complicated, and very robust, and he also came up with some good ideas of how to implement it in practice. Theoretical isolation is 55 dB, and isolation is good down to about 30 Hz. (MSM resonance at 15 Hz, predicted). In practice, it's darn good!
First we started out with an ordinary solid-core door slab (44mm - aprox 1 3/4"). Here's the base blank slab, with the location of the window marked, ready for cutting.
Window hole cut out:
Another view of the door blank with the window hole cut out:
Installing the drop-down threshold seal, at the bottom of the door. The shape is routed into the base layer of the door:
The drop down seal with all three layers of the door in place, glued and screwed together. The base layer is 44mm thick solid wood, and the other two layers are 19mm each, solid wood. Total thickness: 82mm (+/- 3 1/4"). Surface density of complete door: over 62 kg/m2. Each door weighs about 100 kg (220 pounds).
Another view of the layers clamped together while the glue cures.
Now for the frames that the doors sit in. Since there are two doors back-to-back, one in each leaf, he decided to do both frames at once, to keep them lined up properly, as well as plumb and level. So he nailed temporary bracing across them, with blocking between them to keep the separation correct, as well as adding the fabric that covers the gap, and taping it all in place. The temporary blocking and bracing also keeps the fabric taught, so it can't sag:
Then he presented the pair of frames into the rough framing opening, before sliding them in and doing the alignment:
Here are the frames completely in place, shimmed and squared, perfectly plumb and level, and you can also see the temporary thin door that he hung on one frame, so he could close up the room and lock it:
Here's the frames nailed and screwed in place, with the temporary bracing and blocking removed, showing the neat finish on the fabric from this method.
The second set of jambs is now in place here, to create the triple-seals. The nail holes have been plugged and sanded here, and the varnish is about to be retouched:
The inner-door is hung, all three jambs are in place on the frame, but the rubber seals have not been installed yet. You can see the triple jambs where the seals will go, built up from individual layers of wood on the base framing, similar to the way the door itself is built. Also note the heavy duty hinges. Six of them: Three up top, two down below, and one in the middle.
- Soundman--Site-Built-Isolation-Door--112+-Inner-Door-hung--BRAUS--Soundman2020--recording-studio-Design.jpg (88.51 KiB) Viewed 37408 times
- Soundman--Site-Built-Isolation-Door--112+-Inner-Door-hung--BRAUS--Soundman2020--recording-studio-Design.jpg (88.51 KiB) Viewed 37408 times
Inner door detail of upper hinges, with rubber seals in place.
Inner door in place, viewed form the outside:
Both doors in place, seals in place, both open:
Both doors completed, seen from outside:
Both doors completed, seen from inside room:
View from outside, with both doors open:
Detail of the door closer and the seals on the inner door. Note the three complete full-perimeter seals all around the door. Necessary for high isolation.
A word about those automatic door closers: you need them! These doors are heavy (100 kg / 220 pounds each!), and trying to close them by hand would slam them into the frames and jambs every time, even if you try not to, eventually causing things to move, break the seal, or fail. A door closer does the job of closing them slowly and gently, then applies pressure to keep the seals properly compressed, without needing a latch.
So, that's one way to do a pair of doors into your studio. In this case, the studio owner can play two sets of drums at once inside the room, and the neighbor just a few meters away can't hear anything.
- Stuart -
thanks again Stuart. Super helpful to have this walkthrough!
I think the suction is pulling the door away from the seal a bit. This is likely made worse because the door is just a single panel, not bank vault style with several layers of seal. Also because it is a single door, if it was a double door the outer door would be sucked against the seal, presumably lessening the pull on the inner one.