John Sayers' Recording Studio Design Forum Archive

Hi Looking for advice from others who have had to deal with centre beams in their basement studio builds.
My basement is 24x14.5x8 with an additional 16x9x8 ft at the back.
I'm at the structural stage and have to decide if I spend the extra $ to pocket the new beam that will span the main part of the house in the basement supporting the joists. The finished basement height is promised to be 8ft, floor to bottom of joists. The beam will span the length of the front portion of the house 24ft, posts at each end. For an additional $2K I can have the beam pocketed and the joists hung by joist hangers increasing headroom. The beam is 10in. the joists are 8in.
Question 1 - How have have/would others deal with this - would you pocket to increase the headroom or mount the beam under the joists and build a bulkhead - taking away an additional 2-4 in of headroom, and require additional bulkheads for HVAC.
Question 2 - In either case pocketing or flush mounting whats the best way to isolate the ceiling? I can't figure out a way to run floating joists that will not have contact with the beam meaning mechanical contact with the rest of the structure. I was hoping to build a room within a room but I can't see how that can be achieved. Is my best course clips and hat channel?
Question 3- How have others dealt with the HVAC for the rest of the house running through their basement studios? If I pocket this beam I need to isolate each run of hvac to the west side of the house.
Thanks for your help, and suggestions.

Hi "bigsmokeaudio", and welcome!

For an additional $2K I can have the beam pocketed and the joists hung by joist hangers increasing headroom.

If you have the option to increase your head room considerably, and it will only cost you 2k, then I would definitely go for it. A low ceiling is arguably the biggest factor in preventing many basement
studios from having good acoustics. You didn't mention anything about the goals for the studio (please check the rules for posting!) so I have no idea how much isolation you need, or what you plan to do in there, but if you plan to track live drums, for example, then a low ceiling will severely limit your ability to get good sounding "spacious" and "airy" drums sounds naturally. You'd be mostly limited to very close mic'ing and using effects to try to mimic that sound.

So if you have the option, and the price is reasonable, then yes, I would certainly go for it.

Question 2 - In either case pocketing or flush mounting whats the best way to isolate the ceiling? I can't figure out a way to run floating joists that will not have contact with the beam meaning mechanical contact with the rest of the structure. I was hoping to build a room within a room but I can't see how that can be achieved. Is my best course clips and hat channel?

For true "room-in-a-room" construction, your final inner-leaf ceiling and walls have no contact at all with the existing walls, or that beam, or the joists. As the name of the technique implies, they new walls AND CEILING are built as an entirely separate, self-supporting, stand-alone structure that has no connection at all with the rest of the building (except for the floor, of course).

In other words, you build your walls as independent stud frame within the basement shell, with a gap between the outer basement walls and your new framing. Then you put your new ceiling joists across the top of those new walls, leaving a gap above them. The new joists rest ONLY on the new walls. There is no physical connection at all between the basement beams/joists, and the inner-leaf joists. the two are absolutely independent structures. So you have the "outer leaf", which consists of the basement walls (I assume they are concrete block, although you didn't mention that) plus the beam/joists/subfloor/floor above you, and then you have the inner-leaf, which consists of the new framing with drywall on only ONE side of it (not both sides).

The same applies to doors: you will have a pair of "back-to-back" doors for access to the room, with one door being attached ONLY to the outer leaf, and the other door being attached ONLY to the inner leaf.

Question 3- How have others dealt with the HVAC for the rest of the house running through their basement studios? If I pocket this beam I need to isolate each run of hvac to the west side of the house.

Since you seem to be in the design phase for your house at present, you have the incredibly luxury of being able to plan all of these major issues totally in advance, such that they do not affect your studio at all. HVAC is one of those issues. At this point you can move the ducts wherever you want, with just the stroke of a pen, and at little to no cost. So do yourself a huge favor, and route those ducts entirely outside of your studio area. Keep them completely clear of that area, and only run them through areas of the basement where the studio will not be located. The same applies to water pipes, electrical runs, gas pipes, drain pipes, and all other such things. Keep your studio area totally free from those, since they all involve penetrations of your "outer-leaf" ie. the subfloor above you (which greatly weakens your isolation), and they can also take up a lot of space.

HVAC is a huge part of studio design, and in my experience is the part that is least though of, least planned, and causes the most problems. The HVAC system has to be designed in parallel with the studio, NOT afterwards. You need to do all your calculations first, to figure out your room replacement rates, flow volumes, flow velocities, static pressure, sensible heat, latent heat, duct sections, fans, dampers, registers, silencer boxes, and everything else, then you need to incorporate all of that into the overall master plan as you design. Silencer boxes and ducts take up a log of space: they are huge, much bigger for studios than for the rest of the house, due to the need to keep the flow velocity low and the flow volume high. Your isolation plan will dictate if you need one or two silencer boxes per wall penetration, how many baffles they will have, how thick the materials will be, etc.

So plan that very carefully: if I had a dollar for each thread on the forum where people forgot to plan HVAC properly up front, then ran into costly and complex issues later, ...

Ditto for the electrical system: The rule here is that you can allow only one single wall penetration in each room to bring your electrical power into the room, then distribute it from that point with surface-mount ONLY: You CANNOT cut holes in the wall for outlets, switches, light fittings, etc.


- Stuart -

Thanks Stuart,
Purpose of the space is mostly mixing, occasionally tracking drums included as my wife is a drummer.

I'd like to see an additional 30dB of isolation if possible. Not sure if this can happen with a ceiling built with iso clips and hat channel , with 2 layers of drywall and green glue.
I wasn't asking what a room within a room was, I was asking if anyone had ideas to achieve a room within a room given that I have a centre beam hanging lower than my joists either pocketing (additional 2" of beam hanging down, or flush additional 10" of beam hanging down).

I'm leaning towards the pocketed beam as I'll at least add 8" in the centre and possibly be able to incorporate this beam above the ceiling if I drop the ceiling on clips or if I sacrifice another 6-8" for joists that rest on my new side walls, but this much sacrifice is a lot when only working with 8' clear.

Has anyone found any isolation joist hangers? Would something like this be better than iso clips for hanging the ceiling? Typical joist hangers won't offer me any benefit but if my r-in-r ceiling joists could hang on this beam on iso hangers I thought that might offer better isolation and support.

Yeah the planning stage is great for dreaming but as I'm finding its rarely an anywhere you want situation when it comes to actually doing the work.

Any further thoughts? Thanks a lot for any suggestions.

I'd like to see an additional 30dB of isolation if possible

so you are looking for a total TL of about 60 dB? That is do-able, but is approaching the limit of what can be achieved for a typical home studio on a reasonable budget. That is getting close to the flanking limit for the typical way houses are built. In other words, this build has to be planned very carefully, in great detail, and will require a lot of attention to detail. Even small errors can greatly reduce the isolation, when you are talking about high isolation, in the sixties.

... possibly be able to incorporate this beam above the ceiling if I drop the ceiling on clips ... Has anyone found any isolation joist hangers? Would something like this be better than iso clips for hanging the ceiling? Typical joist hangers won't offer me any benefit but if my r-in-r ceiling joists could hang on this beam on iso hangers I thought that might offer better isolation and support.

You still seem to have some misconceptions about what high isolation "room-in-a-room" is all about: If you build it properly, as a traditional fully-decoupled two-leaf MSM system, then you do not need to isolate the beam, or the joists, or the hangers, and in fact there is no ceiling attached to any of that at all! As I explained above, if you build your room correctly, the ceiling rest ONLY on the inner-leaf walls: there is no other ceiling above that. Your beam, joists, and floor form the outer leaf, period. The new ceiling, which is not mechanically coupled to that in any way, is ONLY part of the new room. If you were to also add an additional ceiling below the beam/joists, then you would have a three-leaf system, which would mean that your isolation for low frequencies would be substantially worse.

And if you do only the suspended ceiling (clips plus channel), instead of the fully decoupled ceiling resting on the inner-leaf walls, then you can't get to where you want to go in terms of isolation. Mid 40's is about as good as you could expect. Far short of what you said you wanted...

Yeah the planning stage is great for dreaming but as I'm finding its rarely an anywhere you want situation when it comes to actually doing the work.

Sorry, but I can't agree with that: The planning stage is critical, and should take about 80% of the total time that you dedicate to this project. That's the general rule of thumb. Some say 70%, some say 90%, but 80% seems about right. And planning is most certainly not dreaming: It is carefully laying out in a 3D model, everything that goes into the studio, for the single purpose of ensuring that the actual build goes quickly, smoothly, and with no surprises. If you don't believe me, then I'd suggest that you spend some time reading through the build threads of members who have gone down this path: you'll see that those who don't plan carefully end up spending much more than what they anticipated originally, as they have to take things down again to fix their errors, and very frequently they never actually finish building at all. On the other hand, you'll also see that those who do plan extensively, in great detail, practically always complete their studios well, and they achieve their goals.

So I'd suggest that you put all the effort you can into planning. If you don't want to do that yourself, then it's probably better to hire someone to do it for you, but trying to build a studio without adequate planning is pretty much doomed to failure. Those who don't plan, don't succeed: The forum is littered with such cases...


- Stuart -