Multi-purpose Music/Home Theater/Recording Studio

#16

Thanks. Regarding my 2 layers that I put on the Enermax (OSB + gwb), someone told me that I could first put a horizontal wooden slat. This would create an air space between the vapor barrier layer of the Enermax and the OSB in order to prevent condensation and the risk of rot. I read that OSB can act as a vapor barrier. So moisture could be trapped between the Enermax and the OSB (dew point). However, if the humidity level in the studio does not exceed 50% and everything is well sealed, the risks are minimal.

Is this a good idea (the slats) and would it not reduce the soundproofing?

#17

as long as your vapour barrier is properly placed and sealed, then no, you don't need the slats and in fact could cause issues between the two layers as there is now an air gap - think 3rd leaf type issues.

#18

On the acoustic clips, since there's no supplier in my town, I bought a pack of rubber puck and made a demo to show you how I would use it and if this could be acting the same as the clips.

diameter: 3.75 inches
thickness: 0.5 inch

Is it something that could work (to reduce sound transmission from the studio to the gym) ?

#19

only if the bolt is decoupled from the frame as well. check out the Kinetics Noise Wallmat - see the type of bolt decoupling.

#20

Thanks a lot Glenn. I think I've come up with a pretty good solution. You'll be able to confirm this (I hope) when I start my studio building thread soon.

I apologize for revisiting my previous question about condensation in the wall. I am not questioning your expertise in any way, but since a mistake at this level could have serious consequences, let me double-check with you.

I am in Quebec and we have a very long and often very cold winter. The building code standards here recommend having an air space after the vapor barrier. This is also what a building architecture technician confirmed to me. However, I think that just because a solution does not fit into the standard does not automatically mean it is bad. And the building code does not recommend sealing the layers as you would for a studio...

Can the surface temperature of the Enermax drop below 12 degrees Celsius and create condensation with the air coming from inside? (should I test it with a surface temperature detector?). When i put my hand on the Enermax it's cold but i can't tell what the temperature is...

So if you could review how my current walls are made and reconfirm your recommendation that would be greatly appreciated.

Stef

#21

The simple answer is, build in accordance to code. So if you need a value barrier on the inside to prevent indoor moisture condensing into the insulation, that would be good.

#22

I continue with HVAC design.

Heating:

Radiant floor (already installed)
However, to compensate for a possible breakdown of the radiant floor for a few days, I will put a 30A socket in the middle of the south wall to be able to connect an additional heater.

Ventilation:

I trust my contractor because I have been doing business with him since 2011 for the air conditioner and furnace in the house. I presented my project to him and he suggested the Venmar A160E75RT ERV with the following plan:

Fresh air from outside will be preheated (winter only) by a duct heater. The ducts are 6-inch diameter galvanized steel. There is one fresh air inlet (green ducts) in the gym and three in the studio. However, the studio air inlets will be supplied by a 3-foot flexible acoustic duct (before reaching the grille). There is one stale air outlet (return vent) (red duct) in the gym and one in the studio.

In the gym, the ducts will be attached to the ceiling slats with Ty-wrap and hidden by the suspended ceiling. If necessary, I can wrap them with wool to soundproof them. In the studio, they will be in a soffit (surrounded by wool). The ERV will be suspended from the ceiling trusses by chains with anti-vibration springs.

According to my contractor, I won't hear any air coming out of the grilles. It should be noted that they will be quite far from the mixing position (the nearest grille will be about 12 feet away).

max 160 cfm, min 45 cfm
800 fpm

Air Conditioning:

I'm not sure I'll need air conditioning because the concrete slab is quite cool in the summer. But I'm going to run an electrical wire to the middle of the north wall and leave it in the soffit, in case I need to install a mini-split.

Questions:

1) Does any of this make sense?

2) To run the conduit to the studio, I'm thinking of making a 6'' hole in the drywall to pass the conduit through and put sealant (on the gym side and the studio side) and between the 2 walls put fiberglass around the conduit. Is this the right way to do it?

As usual, any comments or suggestions are welcome.

Stef

#23

one consideration is symmetry to the "noise" from the air system - mechanical noises as well as registers. the size of the rooms as well - what is needed to exchange air 4-6x per hour? if you have 250m3 volume and 4x / hour = 16m3/min x 30% of that space so going with say a 180cfm unit in a 14" duct is roughly 180fpm. then if you expand the CR duct before delivery to the multple supply and return registers in symmetrical positions, you could get that air speed down to say 120fpm or ~2fps - would would be quiet.

#24

If I understand correctly, once I have run the 6'' duct through the 2 walls into the studio (blue circle), I should increase its diameter to reduce the air speed?

: Plan 2D - HVAC-4.JPG (30.9 KiB) Viewed 23076 times

: Plan 2D - HVAC-4.JPG (30.9 KiB) Viewed 23076 times

#25

yes, same for the return as well

#26

In the end, I decided to put the ERV above the toilet, on the same side as the radiant heating system, so I can hide everything at the same time. But the plan remains similar except that the supply of fresh air in the studio (the 3 output grilles) will be on the south wall instead of the north wall.

In this photo we see the ERV and the duct heater.

To run the conduit to the studio, I'm thinking of making a 6'' hole in the drywall (red circle) to pass the conduit through and put sealant (on the gym side and the studio side) and between the 2 walls put fiberglass around the conduit. Is this the right way to do it?

Stef

#27

Hi,

As you can see from my Construction Thread, I went ahead with the ductwork to the studio. In my situation, I don't think I had many options.

I had a recommendation from an architect not to put OSB as the first layer because it will act as a second vapor barrier, and this is to be avoided. So instead I will put 2 layers of 5/8 drywall : 4x10 sheets on the walls and 4x8 sheets on the ceiling. Here is my plan:

LAYER #1 - WALLS

1x3 wood slats nailed horizontally on the studs through the Enermax, every 24 inches (studs are 16'' oc). This creates an air space between the vapor barrier (Enermax panels) and the first layer to prevent condensation. The thickness of a slat is 3/4 inch. The slats do not touch in the wall-to-wall corners.
2x2 square of 1/4 inch self-adhesive neoprene foam (density of 75kg/m3) every 16 inches on the slats to decouple the gwb from the slat.
5/8 4x10 gwb placed vertically screwed every 16 inches on the neoprene squares (to better absorb the screwing pressure and reduce the rigidity of the mechanical bridge created by the screw), with 1 5/8 inches screws, so that the screws do not protrude beyond the slats (total of 24 screws per sheet). Neoprene should not be too compressed. The leaves do not touch in the wall-to-wall corners.

Example for 1 sheet of 4x10

LAYER #1 – CEILING

1x3 slats nailed perpendicular to the trusses, every 16 inches (trusses are 24'' oc).
2x2 square of 1/4 inch self-adhesive neoprene foam every 12 inches.
5/8 4x8 gwb screwed every 12 inches on the neoprene squares, with 1 1/4 inches screws, so that the screws don't touch the slats (total of 36 screws per sheet), The leaves do not touch in the wall-to-ceiling corners.

Example for 1 sheet of 4x8

: neoprene2.JPG (32.37 KiB) Viewed 8574 times

: neoprene2.JPG (32.37 KiB) Viewed 8574 times

SEAL ALL WALL-TO-WALL AND WALL-TO-CEILING CORNERS.

LAYER #2 – WALLS

5/8 4x10 gwb placed vertically (by offsetting the joint by 24") screwed in the first layer every 12 inches (uniform 12-inch spacing across the entire surface) with 1 ¼ screws (just enough to not reach the slat). The leaves do not touch in the wall-to-wall corners.

LAYER #2 – CEILING

5/8 4x8 gwb screwed in the first layer (by offsetting the joint by 24") every 12 inches (uniform 12-inch spacing across the entire surface) with 1 ¼ screws (just enough to not reach the slat). The leaves do not touch in the wall-to-ceiling corners.

SEAL ALL WALL-TO-WALL AND WALL-TO-CEILING CORNERS.

QUESTIONS :

What do you think of this plan?
Is the spacing between each screw in each layer secure enough?
In my case, do I need to leave a gap at the bottom of the sheets before sealing? (or just lay the sheets on the urethane and seal, like the picture below)

Thanks for your help!

Stef

#28

"a recommendation from an architect not to put OSB as the first layer because it will act as a second vapor barrier, and this is to be avoided"

ok by mr - but how are the multiple layers of gwb also not a "vapor barrier"?

#29

"ok by mr"...it means? (I'm french canadian...)

I haven't spoken to him personally. A friend of mine asked him if what I wanted to do was correct (OSB + gwb). He said that since there is a lot of glue in OSB it acts as a vapor barrier and since I already have Enermax which is a vapor barrier he doesn't recommend doing that. Instead, he recommended that I use a resilient channel with 2 layers of gypsum (but I prefer to use slats to have more strength when hanging things from the ceiling).

So I had some drywall delivered and returned 45 sheets of OSB. It was 3/4 OSB for flooring (Dryguard).

That said, I don't question your studio design knowledge. I don't know much about construction. But I'm in Quebec, and you advised me to follow our building code. So I think this architect advised me based on the building code (and perhaps his experience). So I prefer to play it safe.

Now, can we go ahead and see if my design with 2 gwb is correct? It would be really appreciated if you could answer my three questions above.

Thanks again for your time.

Stef

#30

sorry meant "me" - yes, OSB in theory "seals" better than gypsum wall board - however, your actual vapor barrier better be stopping most if not all of the moisture exchange, otherwise you're just getting wet gypsum... ergo, an additional layer of mass (e.g. OSB) isn't a concern. this is just basic fundamental building stuff.

yes your gwb approach is ok.

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