Some questions regarding door and doorframe

Hello everybody! I'm designing a studio with separate controllroom/rec room, it's 2 layer wall between with separate frames(or actually one of them is 15cm - approx 6" thick brickwall) and one is going to be 3leaf thick drywall design with airgap separating the drywall construction and the brickwall. I'm going to install a dual door design, and have some questions regarding construction before I begin. First off, i've seen this thread: http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=12664 And I wonder, is it neccessary to install two doors of this design, or is it going to be overkill? I know it's no use of doors better than the walls, but with these walls I think I will get rather high TL and the use of heavy door designs might be justified. another question is: is this kind of dual cleat/weather strip design neccessary, or is just a single one okay? second question: regarding framing around the door, in this thread there are some recommendations: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4162&postdays=0&postorder=asc&start=15 Whats the purpose of the header above the door? Isn't it enought to just install a regular piece of frame above the door? Is is neccesary to use 3 vertical studs on both sides of the door? Of what reason, if you have horizontal ones strenghtening them up I mean isn't it enought with 2 of them? This is an illustration of a design I think about using, is this to weak? http://img17.imageshack.us/img17/2059/doorframe.th.jpg 3rd question: I'm going to decouple the framing system from perimiting walls of the new drywall i'm putting up, by connecting them on 6 spots with one kind of hanger like those http://www.professionalacousticsco.com/rsic-dc04.html#f3 (not exactly that one but one similar, capable of 25 kilos, approx 45 lbs of weight handle per hanger) and a strip of acoustical rubber for the frame to stand on on the wall, taking all the weight of it. When opening the door, if very heavy, the wheight of the wall is changing from vertical to horizontal to some extent, will the wall be able to handle the extra weight from the door when opened, if using 6 of those hangers for a wall approx 4 meters(13 feet) long and 3.5(11,6 feet) high, with widow and 3 leaf drywall? Also, I'm thinking about what kind of sealing system i'm going to use for the door, I saw those ones http://www.locksusa.com/taymor_doorclosers.asp but I wish to be able to keep the door open for communication between rooms without talkback mic, is there any kind of strong magnet strips that you can install in the frame and door, keeping them sealed? Thank you all for a great forum, too much benevolence around here :mrgreen: Cheers Ossian

Osse wrote:

I wonder, is it neccessary to install two doors of this design, or is it going to be overkill? I know it's no use of doors better than the walls, but with these walls I think I will get rather high TL and the use of heavy door designs might be justified. another question is: is this kind of dual cleat/weather strip design neccessary, or is just a single one okay?

That's all a matter of opinion... In my opinion, doors are the weakest link in the entire build process. While the theory of not needing any more mass than your walls and a single seal, is generally accepted as fine, but in practical terms, I disagree. Unless you are a master carpenter, or employ a master carpenter for your doors, there will be imperfections in the door assembly that reduce the overall effectiveness of the seal. It may be .5mm gap or something not perfectly square. I'm finding that adding a bit of additional mass, using the double seal, double caulking edges, etc. will make up for the real world of imperfections.

second question: regarding framing around the door, .... Whats the purpose of the header above the door? Isn't it enough to just install a regular piece of frame above the door? Is is neccesary to use 3 vertical studs on both sides of the door? Of what reason, if you have horizontal ones strenghtening them up I mean isn't it enought with 2 of them?

With Rod's Superdoor and/or any decently built isolation door it's going to weight at least 350 lbs... up to 500 lbs, or more! You need that frame stiff and massive enough to hold that mass perfectly level for the next 30 years. Standard framing lumber is NOT going to handle that mass without sagging, twisting or distorting in one plane or another. IMHO, you cannot provide too much mass, bracing or stiffness to the frame. As an example, here's my loading dock door framing; The header is a 2x8 box frame filled with R-19 insulation and caulked. The hinge side is the left side with 5 2x8's. The right side is 2 2x8's. The door frame which went in, is an additional 2x8 frame. All of the interior door frames are boxed 2x12 headers filled with insulation and caulked, with double 2x6 vert studs with 5/4" stock door jambs.

3rd question: ...When opening the door, if very heavy, the weight of the wall is changing from vertical to horizontal to some extent, will the wall be able to handle the extra weight from the door when opened, if using 6 of those hangers for a wall approx 4 meters(13 feet) long and 3.5(11,6 feet) high, with widow and 3 LAYER drywall?

Again, you want the frame to be stiff and massive enough NOT to allow that change of weight to occur. If it does, eventually, that door will likely come down!! OR possibly worse... the door AND part of the wall! If that happens, then there's the real possibility that part of the ceiling will come down too!!!

Osse wrote:

second question: regarding framing around the door, in this thread there are some recommendations: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4162&postdays=0&postorder=asc&start=15 Whats the purpose of the header above the door? Isn't it enought to just install a regular piece of frame above the door? Is is neccesary to use 3 vertical studs on both sides of the door? Of what reason, if you have horizontal ones strenghtening them up I mean isn't it enought with 2 of them? This is an illustration of a design I think about using, is this to weak?

The header serves two(2) purposes. The one most important to you in this situation is the header maintains the proper distance from stud to stud, prevents bowing or twisting of the studs in the door at rest position od the door open position. The primary purpose is to support weight loads as vertical members are spanned across openings. Depending on the door(s) you purchase or build, the weight can be considerable. By that I mean it can be high! This is one reason why the use of a double stud is recommended, to maintain a straight frame that will carry the loads placed on them. Frame it the way you are seeing it framed and you will have a better door opening then trying to modify or save a few boards here and there. My door has 1/8 inch lead, 1/2 inch densguard sheetrock and 3/4 inch cedar laminated on it. It is heavy!!! edit: I see that MadMax is posting while I am making this post...he has some good pictures of how this is correctly framed including the blocking at 48 inches from the ground up to maintain the rigidity of the frame.

Just a note, Doors shouldnt be looked at as just a door, if not as a whole system. For instance, a 55 STC rated door, will end up finally at just STC49 when properly installed and sealed with apropiate rubber seals and stops. That means, you NEED to make your door not only the same mass as your walls, but a lot more! A STC40 rated door will end up to STC36 in the perfect scenario, so that will be even worse with real life imperfections.

"the wheight of the wall is changing from vertical to horizontal to some extent, will the wall be able to handle the extra weight from the door when opened" With regard to your third point. I just finished (bar the roof) my vocal booth. a free standing 2.65x1.8m with a height of 2.4. The door I attached weights about 38kg. NOw your right when I open it, there is some movement in the frame when the weight shifts. I'm hoping that once I get the ceiling joist, it will stop some of that movement- but if not are those hangers the way to go?