SFGate

Dytecture Most garage floors are constructed with slab on grade method, as the cost of supporting vehicles with a finished basement is too costly to justify the added space. If you are just in the planning stage, it would be best to avoid any basement area under the garage.

apple_pie_order Agree with Dytecture. Over the garage would be better. There are fabulous home theater rooms on houzz.

Carolyn Albert-Kincl Design The popularity of home theatres seems to be fading. For a few years every big house had to have one, but then many people found that they watched more TV and movies in the family room and were not using their media rooms. I'd love to hear what others think about whether they use their media rooms.
Carolyn Albert-Kincl, ASID

orangecamera Putting it under the garage would require lots of pillars to hold up the garage. Not what you want in a theater. In fact, I don't think I've ever seen anything under a garage.

Linda I recently visited a home for sale with a storage area under the garage. It was a very sloping lot so it would have taken a tremendous amount of fill to get to an on grade slab. The entry to the underneath space was a slightly shortened door to a dirt floor storage space which ran under the breezeway and the garage. Obviously parking garage have usable space underneath the parking floors, so it all depends on the lot itself and whether the space is so precious that building underneath parking is a given, an option, or a nonstarter. I would think on a cost per square foot scale, that would be very expensive space.

Dennis webb construction Linda

I am a building contractor in Sausalito, ca I am in mid stream on a basement conversion where we had to carve under the house, we could not add on top of the house as views are a real ssue here, water proofing and heat are challenges , I have a slab on grade with a sleeper sub floor system, if i had the option I would use a jost system as heating would not be a problem as we could run it under the floor, you can achieve a better insulation value, and have a lot more options using a joist system vs adding fill and pouring concrete, i think a wood floor on a joist sysyem is a lot better for you if you have any back or sciatica problems as concrete and stone seems to travel right through your body, water proofing is achieved easier and less money, you then could add or delete some thing with ease as its not imbedded in concrete.

All the best
Dennis Webb

Linda Dennis, your project is a perfect example of when using the space under a garage is a reasonable approach. I didn't end up buying the house with the raised garage, but it was notable as the only example I've seen around here where the garage floor was not slab on grade. (I'm in metro Chicagoland)

In my own house, my kitchen floor is 4 inches of cement, with sleepers and a douglas fir subfloor. When we removed the original flooring, the wood subfloor was so pretty we decided to sand and finish it despite the face nails and some movement issues. I love wood floors and I certainly agree with you about standing on concrete and stone surfaces.

orangecamera I'm intrigued to learn about rooms under garages. I honestly had never heard of it before. I like learning new things :) Can someone explain what a "sleeper" is? Thanks.

Linda Sleepers are the flooring version of furring strips for walls. The sleepers are strips of wood laid on top of the concrete then the subfloor is put on top of the sleepers

For another bit of useless info, Americans describe wood supports under the rails as ties while Brits call them sleepers.

orangecamera Thank you Linda. Gotta love the English language!