How To Build A Soundproof Shed - Part 2

FREE Soundproofing Workshop:

My contractor, Henry Thompson has been working on a soundproof studio here in Nashville that is built within a prefabricated shed. This is part two of the build series and it will go over the double walls, insulation, hat channels, drywall and installing the window. If you want to see part 1 of the series you can watch it here:


1) Double Walls 

In part one we talked about adding mass to the outside wall. In this lesson we are going over the double wall system. Henry and his team built out a seperate wall 1 inch from the existing structure to soundproof all the walls. He used special acoustic clips called IB-3 clips to attach the inside wall to the existing structure. These clips are specially designed to reduce sound transmission traveling from the existing structure to your inside walls. 


2) Spray Foam

Now spray foam does not help with soundproofing, but it does help with moisture issues. Because the roof is not vented Henry opted to use spray foam on the entire existing shed walls and ceiling. This allows proper insulation so the ceiling does not have condensation build up. This also helps tremendously with ensuring the roof system is airtight. Traditionally a cathedral style ceiling like this one would need soffits to vent properly. The problem with this method is that it means your ceiling doesn't get the double wall system you need for proper soundproofing. 


3) Putty Pads and Insulation

After the spray foam was installed, Henry and his team installed putty pads around all outlets and electrical boxes. This ensures that sound cannot easily transfer through the boxes behind light switches, outlets and overhead lights. Next, the team installed regular pink insulation in all of the wall and ceiling cavities. This is an important part of the soundproof wall design and the spray foam is not enough for proper soundproofing. 


4) Hat Channels and Loft Floating Floor 

Henry and his team installed hat channels and IB-1 acoustic clips on all of the ceilings in the studio and along the beam supporting the loft. The hat channels decouple the two layers of drywall from the ceiling making it soundproof. The loft posed a difficult soundproofing problem. In the end, Henry floated the loft floor using some U shaped auralex floor pads. These are not usually something I would recommend, but in this situation we had to improvise some to soundproof the loft as best as possible. Henry added mass to the loft floor to help isolate it from the entryway below. 


5) Drywall, Green Glue and Acoustic Caulk 

Once the insulation is in and the hat channels are installed the next step is adding the two layers of 5/8" drywall with Green Glue in the middle. The two layers of drywall add the needed mass to soundproof our walls and ceiling and the Green Glue helps stop lower frequencies and increase isolation due to damping. Once the drywall is in place they caulked the floor to wall, wall to ceiling and all corners with acoustic caulk to make sure the entire system is airtight. 


6) Barn Doors

The shed came with two barn doors. This also posed a challenge to our team because the doors are large and not very heavy. Henry came up with the solution of adding two layers of 5/8" drywall with Green Glue to the back of each door. The doors will not be soundproof until the project is complete, but this will add some much needed mass to the front door system. 


7) Mini Split (Heating and Cooling)

For heating and cooling needs, Henry and his team installed a Mr. Cool mini split on the back floor joist under the loft. This also allows plenty of space for the piping to run through the walls and out to the condenser. Remember, mini splits offer quiet heating and cooling, but they do not offer fresh air. For that you need a separate ventilation system. 


8) Window 

Lastly, Henry and his team installed a large outside window on the front wall. This window is made of laminated glass and is thick to help stop sound. Henry created a frame for the window to sit in and then sealed any air gaps using DAP AMP, which is an all weather sealant. This sealant is important to keep the window airtight. Once the sealant was in place, Henry installed the outside trip around the window using a nail gun.