Under our garage is a cement room (23' x 20', 8' high). We added it to the construction plans as a storage room, with the option of using part of it as living space. Everyone seems to think it would make an amazing home theater room… ^_^
Well, before we can even use it effectively for storage, I need to get more lights installed. Framing the room seems a good way to make the space more usable, and get a roof I can attach lights to. But this raises some unusual (for me) questions.
How do I frame the ceiling? Do I just follow the basic plan for framing corners so I can attach sheetrock, or are there other concerns?
We plan on putting a wall through the middle and dividing the room. So the final spaces will be approximately 19.5' x 11', with ceiling members across the 11' dimension. What dimension lumber do I need, for the ceiling? 2×4? 2×6?
There is a connection for the central air system in one wall: a "source" against the ceiling, and a "return" against the floor. I believe I can simply put a grate over the return once we finish the wall, but do I need a minimum depth to the ceiling to support running ducts across the room?
These are the only major concerns I have planning this, but if anyone sees anything likely to come up, feel free to warn me. ^_^
Best Answer
If the ceiling is not structural and is only there to hold up the drywall, you can get away with using 2x4s. 2x4s at 16" on center should easily span 11', while supporting only drywall.
Basically your going to support the ceiling rafters with the walls, so you end up with a structure like this crude MS Paint image.
The basic idea is to build a room inside your room.
If you are planning on using recessed lighting or HVAC ducting in the space, you may want to go with 2x6s for the joists (to allow enough room to install everything).
If the ceiling joists are going to be load bearing (especially if they are supporting the parking surface of your garage), you'll want to consult a structural engineer (and you'll likely end up using I-beams tied into the concrete walls as joists).