Scotth's studio build thread. 95% complete..

[scotth]

I started planning (i.e. dreaming) to have a music room before long before I had a chance to build a new home.

For reference I had Rod Gervais' "Home Recording studio: Build it like the Pros" and to fill in the missing pieces I signed up at this wonderful forum. I spent countless hours planning, measuring and thinking about how everything would come together well before I took my first swing of the hammer.

For your reference; I'm an electrician by trade, and have done many home renos in the past. I also owned most of the tools I needed to complete this job.

What I wanted: I room that I could have band practice in at any time of the day. I also have considered, one day, using the room to do professional recording and mixing.

My wife and I were fortunate enough to have a custom home built for us in 2015 -2016. A music room was part of the plan from the beginning. With that in mind, we had the basement built accordingly. ( No window in the music room, 8'4 ceilings, in floor heating)

From there, I built a "room within a room" complete with an independent ceiling. All of the walls had a double layer of 5/8" drywall with green glue in between each layer. I also added a double layer of 5/8" drywall to the underside of the existing floor.

For a finished ceiling I built a "reverse ceiling"; the drywall is on top of the ceiling joists with insulation in the middle and burlap fabric as a finish material. (the idea is, that you end up with your whole ceiling being sonically treated.) That's the concept, read further to see how it turned out.

The finished room dimensions came to 10'8" x 18'4" with ceiling heights of 7'11 and 6'9". Size wise, I can fit a 4 piece easily, and could probably cram in a 5th or 6th. The big question will be how well the a/c keeps up in the summer with that many people.

Here's the room before I started, with some pics of the ceiling joists to show what I was up against

[scotth]

Here's the prints and drawings that I drew up.

The music room is directly beneath the main bedroom. The two kid's room are upstairs, on the opposite side of the house.

[scotth]

the 1st construction step was to "bulk up" the underside of the floor with two layers of 5/8" drywall. the edges were filled with backer road and acoustic sealant. This was very long, very dirty, tedious process. Lots of measuring, cutting and re-cutting. I also made sure overlap the joints in the 1st layer of drywall.

I used drywall screws to fix the drywall to the OSB floor. I checked , re-checked the length of screw that I could use without going right through the main floor!

[scotth]

Next step was to build a bulkhead around all of the mechanical systems serving the master bedroom. This was the 1st planning mistake; I should have designed the layout of the house so that mechanical ran through a different part of the house. The bulkhead had a serious impact on the finished height of the room.

[scotth]

Finally, the fun part! framing the walls. (One tool that I did buy was an air powered framing nailer ) This was pretty easy, basic wall building. just 16" centres ons the east/west walls and 24" centres on the north/south walls. It's too bad the fun step is also the quickest step.

I realized that I didn't take any pics of the new ceiling joist framing, but it's just 2x4s ran at 12" to centre. ( the plans say 16" centres, but I went with 12" on the advice of the building inspector.

[scotth]

after the walls were up, I rough-in the electrical system. This is my trade; no problems here.

It's just one circuit doing all of the plugs and LED lights. I put in a few double plug outlets, because I can and I hate power bars. At the door at I put in two 3 gang switch boxes. 1st box does the lighting, separated into 3 zones. 2nd box does switched plugs mounted at ceiling height and one switch for the exhaust fan. I'll use the switch plugs for accent lighting.

[scotth]

next step drywalling. two layers of 5/8" with green glue in between. Again, great care was taken to ensure that all the joints on the 1st layer were covered by the second layer. (this led to some unusual length cuts)

My wife and dad both occasionally helped with this as I needed with the lifting. My wife also enjoyed putting in the screws.

After drywall was done, I hired a taper to come in and do the taping and mudding. I've never taken the time to learn how to do this; it's very hard for me to get right. This is the only person I hired to help me. He did an amazing job. Money well spent.

[Soundman2020]

Hi there "scotth", and Welcome to the forum!

Thanks for documenting your build here.

However, it's a pity you didn't find the forum BEFORE you started building, as there's several things you could have done better.

First, a couple of questions:

What I wanted: I room that I could have band practice in at any time of the day. I also have considered, one day, using the room to do professional recording and mixing.

What was your design goal, in terms of isolation? In other words, how many decibels of transmission loss did you design for?

in floor heating

How did you deal with the issue of anchoring your new inner-leaf walls into that floor, without damaging the heating system?

I also added a double layer of 5/8" drywall to the underside of the existing floor.

I guess you mean: "the existing floor above this room" ?

For a finished ceiling I built a "reverse ceiling"; the drywall is on top of the ceiling joists with insulation in the middle and burlap fabric as a finish material.

The correct term is "inside-out" ceiling. We know it's the correct term, since John Sayers himself invented this concept, and that's what he calls it...

Question: How did you build that? How did you get the drywall on top of the joists?

(the idea is, that you end up with your whole ceiling being sonically treated.)

That's part of the idea, yes, but that's not the full concept, nor is it the complete treatment that your ceiling will need.

I'm also wondering why you built the ceiling inside-out, but built the walls conventionally: you could have saved a lot of space by building those inside-out as well.

with ceiling heights of 7'11 and 6'9".

If your original joist height was 8'4", and you built inside-out, how come you ended up with such a low ceiling?

The big question will be how well the a/c keeps up in the summer with that many people.

Ummmmm... then there's a problem! That implies that you did not design the HVAC system correctly. That should have been part of the original HVAC design: The system should have been dimensioned to deal with the worst-case sensible heat load and latent heat load, on the hottest day of mid-summer with the highest humidity, full occupancy, and a ton of gear, instruments, lights, pizza, coffee, etc.

The other thing I don't see in your photos, is ANY of the HVAC system: where are you silencer boxes, for example? Where does the fresh air come from, and where does the stale air go? What ventilation rate did you use for the HVAC design? What velocity at the registers?

Here's the prints and drawings that I drew up.

Please post larger versions of those: it's very hard to make out the notes and dimensions on some of them. Also, please post the final actual plans that you built from, or better still, your full 3D model of the studio.

the 1st construction step was to "bulk up" the underside of the floor with two layers of 5/8" drywall. the edges were filled with backer road and acoustic sealant. This was very long, very dirty, tedious process. Lots of measuring, cutting and re-cutting. I also made sure overlap the joints in the 1st layer of drywall.

I used drywall screws to fix the drywall to the OSB floor.

WHY???? That is NOT the correct way to "beef up" the sub-floor above you. The correct way is to hold the drywall in place with cleats, at the edges. By screwing in thin strips instead of allowing them to act independently, you have decreased the isolation of that floor at some frequencies, notably around the coincidence dip. You have added mass, yes, but you added by basically sticking it to the existing mass, the same as gluing layers of a wall together. This is not good...

The bulkhead had a serious impact on the finished height of the room.

Right, but it only needed to affect that specific part of the room, not the entire room...

This was the 1st planning mistake; I should have designed the layout of the house so that mechanical ran through a different part of the house.

And you probably could have re-routed some or all of that in various different ways, once you realized the mistake.

(One tool that I did buy was an air powered framing nailer )

Smart move! It goes MUCH quicker like that.

I realized that I didn't take any pics of the new ceiling joist framing, but it's just 2x4s ran at 12" to centre.

Say what? You sued 2x4's to span those distances with those loads? Did you not check the span tables, and/or get the advice of a structural engineer?

the plans say 16" centres, but I went with 12" on the advice of the building inspector.

I'm VERY surprised that he would approve that! Was he aware that you would be using two layers of 5/8 drywall on the ceiling, with GG? I'm VERY skeptical that your ceiling is able to support the load safely. What deflection did you calculate for? I'm afraid you have shot yourself in the foot there, since I don't see that you'll be able to hang anything acoustic treatment from that. A hard.backed cloud, for example, is heavy, and is anchored to just a few points. I very much doubt that you'll be able to do that, with just skinny, flimsy 2x4's up there.

I'm also very confused by your inner-leaf wall photos: they seem to show that the wall tops are attached to the existing joists above you????

....

I'll keep on commenting, as you keep on posting further details...


- Stuart -

[scotth]

air supply/air return:

I did my take offs from the duct work outside of the room, and ran flexible duct, inside their own chases, into the room.

[Soundman2020]

after the walls were up, I rough-in the electrical system.

Why are your electrical boxes located BEHIND your drywall? That implies that you have to cut huge gaping holes in your drywall, which totally trashes your isolation....

and one switch for the exhaust fan.

What exhaust fan? Why do you even need that? If your HVAC system was designed correctly, the AHU should be moving the air. Or was the static pressure of your ducts and silencers too high for that, and you had to add a booster fan?

....


- Stuart -

[scotth]

interior ceiling construction.

I built frames out of 1x2s that fit inside of the ceiling joists. The two layers of drywall sit on top of the frame. I then added 1 1/4" Roxul safe and sound to the remaining room inside the 2x4 joists. I finished it off with burlap.

*another issue that I had with the mechanical is that some joists were used as a return air for upstairs. I could not do an inverse ceiling in this area because it would have greatly reduced my sound isolation. I had to build the ceiling conventional style here. It's about a 3' section at south end of the room. I added a cloud with some pot lights here.

[Soundman2020]

drywall 9.JPG <---- that one clearly shows that your INNER leaf drywall goes all the way up to your OUTER leaf joists.... Therefore I'm guessing that isolation was not really a priority here at all, since you won't be getting much...

drywall 3.JPG <----- that one clearly shows some typf of very small HVAC duct, with NO silencer box, feeding into a contraption that rotates the ar flow through 90° and RESTRICTS the airflow at the register, thus greatly increasing he airflow speed.... WHY???? Why on earth would you do that, if you read Rod's book?

I did my take offs from the duct work outside of the room, and ran flexible duct, inside their own chases, into the room.

Why did you use that size duct? What flow rate and flow velocity did you calculate? What is the static pressure of your studio HVAC system? Is your current house system capable of dealing with that? You did check, right?

....

- Stuart -

[Soundman2020]

duct chase 2.JPG

duct chase 3.JPG

duct chase 4.JPG

All of those clearly show a sudden 90° bend directly into the room, with no silencer, no flow control....


return air 1.jpg

Shows several sudden turns, in a small diameter duct.... That's a very high static pressure drop, right there, for each of those... I'm not at all convinced that your existing house HVAC system will be able to handle that large extra load....

....


- Stuart -

[scotth]

more pics of the ceiling...

[Soundman2020]

I built frames out of 1x2s that fit inside of the ceiling joists

you used 2 x 2 framing????? With two layers of 5/8" drywall on top????? And your inspector approved that????

I could not do an inverse ceiling in this area because it would have greatly reduced my sound isolation.

Ummm.... that's not true. With correct design, it would have been possible. The ONLY thing that matters for MSM system design, is the mass on each leaf, and the depth of the gap between them. Do that right, and it does not matter if you did it with conventional or inside-out construction. By the way, what is the MSM resonant frequency of your ceiling? You DID calculate that, right?

finish ceiling 5.JPG <----- I may be wrong here, but it certainly looks like you cut a hole in your ceiling there, to fit in that light pot... Thus trashing your isolation...

....


- Stuart -