Can someone explain the elevations of main floor and garage slab. The garage slab slopes to the front for drainage does it not. Is the garage slab the same height as finish grade outside the front. Do you like to have the house the same height as the garage slab or step up. What about the max backfill height for a concrete foundation wall. This stuff is confusing. What height should I put my house. What about steep driveways. I wish I had a flat lot with a flat driveway so I could hang out and wash my car easy. Thanks dudes!
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I'm sure you'll get more replies soon, but I would say garage slab should be an inch or so above grade and like you say, sloped to the door for drainage. I had a house with sliding glass doors on a slab on grade once and every time it rained we worried about water coming in. I'd put the house up at least a step--usually the foundation wall ends 8" (one block) above grade and then with the mud sill and floor joists and floor, your finish floor would be like 19" above grade. Unless you build house on slab, I would think at a minimum your floor would be plate plus joist width plus sub and finish floor above grade. In my area (Michigan) the higher above grade the better! (within reason)
I,m in very deep south so my answer might not apply. all slabs must be 18 inches above grade. garage 4 inches below this. slope to door does not matter here due to no snow, but still good idea. all building must be above elevation 13 ( 13 feet above sealevel) so even if slab 18 inches above grade but elevation under 13 house must be raise above 13. House on poles etc.
most places want the geerage 4'' or more lower then the main house..why you ask? Fumes from Gasoline ..stays lower that way
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
"most places want the geerage 4'' or more lower then the main house.."
Durn I must have really misread those plans.
My house is 4 ft lower than the garage. And that is the 2nd floor.
But to make up for it I go up from the first floor 4 ft to get to the basement.
It depends somewhat on the layout of the land. For example, if the land sloped from right to left, and the garage was on the left, it might be several feet lower than the house, with several steps inside.
Having said that it can be affected by fitting the house to the land, here are some general guidelines.
The garage slab is always lower than the floor of the house into which it opens to reduce the chance of heavier than air gasoline fumes from entering. This distance is regulated by local code. In some places it's only a few inches, in others it's a foot or more.
The garage floor nearly always slopes. Generally, it slopes from back to the garage door about 2 inches or so. In a careful installation the front two corners flare up just a bit (say 1/2") so water flowing towards the garage door from the back of the garage goes out the door instead of pooling in the corner. In some climates with long cold winters, some folks instead slope the floor to the center and install a floor drain, because water running out under the garage door will freeze and stick the door to the floor. Some areas may prohibit floor drains for environmental reasons because it's too easy for oil or antifreeze to go down the drain.
The portion of the slab that sticks outside of the garage door back to behind the door should have a steep slope of 3/4". Sort of a beveled edge for the first 8" or so. That ensures that rain that runs down the face of the door runs out away rather than in under the door.
I like to see at least 2" drop of the grade of the driveway within the first few feet. Often there is a concrete apron, separate from the slab, as the first 18 to 24" rather than running asphalt right up to the garage slab. This apron should slope 1". The apron must be separated from the garage slab by an expansion joint, typically 1/2" or so.
Of course, if the garage is below the level of the road, a simple 2" rise just before the garage is not enough to keep water from running down the driveway right into the garage, and other design features have to be incorporated.
As far as what height to site your house, that depends on a lot of things, too long to discuss here. Too low and you are inviting all sorts of problems with rot if the siding and framing are too close to the ground. All the wood needs to be at least 8 to 12 inches above finished grade. But if you put your house much too high, it looks stupid, like you plopped a house just anywhere and piled up dirt around it. A fine home looks "just right" for the natural surroundings, as if it belongs precisely where it is.
Thanks for all the great info. In BC the garage door just has to be fumed sealed. You make a complicated sugject sound easy.
This is actually another response to your closed posting about siting your house--on "Fine Homebuilding" archives there's an article on siting for solar advantage, view, etc. Sounds like what you were looking for. If you have your own past issues, it tells you which issue. Sorry I didn't write it diwn, but it should be easy for you to find the listing.