Garage Floor Requirements?

Old 05-05-11, 06:02 AM
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Garage Floor Requirements?

I have looked for garage building codes and can't seem to find my answer. Any help would be appreciated. I would assume that a garage floor needs to be made of non-combustible material? I would assume that the entire floor would need to be made of this material, even areas that won't be used for parking?

Help me brainstorm here. Here's my situation. I plan on building a detached garage on a gentle slope. I plan for the parking area of the garage to be about 25' deep, and then an additional 10' of shop area in the back of the garage. The way the land slopes, There would be space under the rear of the garage (where the shop would be) to have an additional storage space. Like a walkout basement.

Would the entire main floor have to be concrete, or could I transition to something else for the shop area? I would assume that this idea would be cheaper than running steal beams and poured concrete over the 10' basement area?
Old 05-05-11, 06:58 AM
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If you intend to file plans with the local building dept, I would hire an architect. The floor would be concrete with the proper footings. An architect would know what's required. My guess is that a ribbon footing is required.
Old 05-05-11, 08:23 AM
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Generally a detached garage with no finished living space (especially bedrooms) does give you more flexibility than if it were attached to the house. There may be a distance that the garage must be away from the house to free you from many of the fire related codes. I don't know of any codes that would prevent you from having a wood framed floor for the shop area and honestly I don't know of a code that says the parking area needs to be concrete. You would have to follow your codes for general construction of a permanent structure like: footings, walls, roof and electrical...
Old 05-05-11, 09:45 AM
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I doubt it's necessary to hire an architect for a garage design that doesn't include living space.

IRC2009 (current for us here in NM) states:
"R309.1 Floor surface. Garage floor surfaces shall be of approved noncombustible material.The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway." (Their emphasis.)

"Approved" is a function of your local building codes, so you need to check with your planning and zoning/code enforcement department(s) for what they approve.

Pilot Dane nailed it on separation. There is a minimum distance inside of which the garage is considered to be attached for fire code purposes. Primarily this means you will have to provide at least 1-hour fire rated wall coverings on the side facing the house if the separation is too narrow. Again, check with your local officials.

Good luck with your project.
Old 05-05-11, 11:07 AM
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If the wood floor wasn't an issue as far as fire code, you would probably have to have a wall or large curb to prevent vehicles from driving on the floor that wouldn't be able to support them. You should talk to your local building department to see if the wood floor is a problem. I think you might be able to do it.

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