Building My Studio: Part 3 (The Subfloor)

The last article left off with the floor covered with a plastic sheeting, to prevent moisture from seeping in through the foundation. Additionally, the outside of the room had been framed with horizontal 2x4 studs, which not only held the plastic sheeting in place, but provided the foundation for building the subfloor.

Many studios use 2x4 studs as the basis of their subfloor, essentially elevating their floor by approximately 3 1/2 inches. This provides for an easy way for cabling to be ran under the floors, but also is a step that could lead to better isolation from the rest of the building and improved acoustics in the room.

In my studio, I chose to use 2x4 studs, but instead of standing them "tall", they were laid on the "short" side of the stud. With my limited ceiling space, this essentially gave me 2 more inches of height in the room by laying the studs on the short side. At the same time, this still allowed me to obtain some improved isolation and acoustic properties in my room.

"Uboats" are a popular way of floating the floor, and in areas where isolation is critical, are a valuable item to consider in your floor construction. I am on the lowest level of our home and well removed from train tracks, highways, and other low-level noise that comes through the floor, so did not feel that my money was best spent on this type of isolation. Additionally, using the uboats would chip away at my ceiling height - something I had determined from day one was a top priority.

My floor was secured directly to the concrete. Caulking was used to help keep the integrity of the seal created by the plastic.

Before laying my floor, I carefully considered my initial and future cabling needs, and planned channels into the floor to allow cabling to easily be routed.

The floor was assembled like a spine and ribs. The "spine" running down the middle was a main channel to connect the front and back of the room, and the ribs allowed channels of cabling to the sides of the room. This structure also helped create what I feel to be a more rigid floor, by using shorter lengths of wood. The 2x4 studs were carefully hand selected to make sure the floor was level and strong. In this photo you can see that I have about 1/2 of the main room done.

No pneumatic driver used, I pounded all those nails into the concrete by hand....

While building the framing of the subfloor, I also built in an audio access box - leaving plenty of room for future expansion. Originally, I built 1 in the front and 1 in the back, with the assumption that I might have my main desk in the front, and a rack of gear behind me as well. Ultimately, I opted for a better designed desk so that I could eliminate the rack, and I removed the back access box. This was the one item in my studio that I changed plans on partway through. Luckily, it wasn't hard to fix, but I did learn a lesson!

Once the "ribs" were all done and the subfloor was completely framed, I ran high-quality cable to all the necessary locations.

Next - I put a special 1/16" thick foam tape on top of the studs. After much research, I felt that this would give me a great deal of bang for the buck - helping to decouple the floor top from the frame, without costing a fortune or eating up my ceiling height.




















The floor was then insulated with 2" thick Mineral Fiber (which would compress to 1 1/2" once the top of the floor was on.) The Mineral Fiber has excellent insulation and acoustic properties. Filling the floor prevents the cavities from becoming reasonating chambers, helps control the bass response in the room, and can aid in isolating the studio.



Once this was all completed, it was time to lay down the actual subfloor. Some studios will do multiple layers, using multiple materials. Again - considering my location, my budget, my desire to preserve ceiling height, etc - this was not the best option for me. I chose to use good quality plywood. I am not 100% positive, but I believe I used the 5/8" thick variety. Don't use less than 1/2" thick plywood, and if you use 1/2" ply, keep your bracing close together in order to make a strong floor.

















Before securing any pieces to the floor, I fit them all together like a puzzle. Once I was satisfied everything was where it needed to be, I secured the floor using screws...LOTS of them. Using screws makes for stronger construction, and ensures a rigid floor that won't be squeaky.


Rough spots were sanded, the floor was checked to make sure it was level, and seams were given a light rubbing with caulk.


Up next - Altering the room acoustics with a built in bass trap and creating more angled surfaces in the studio to help keep those pesky room modes and nodes under control...