pitch on slab

[PaulS]

I have a garage plan that calls for a monolithic slab with a 2" pitch toward the garage door. It looks like the walls are bolted directly to the slab. My question is, wouldn't that make the whole frame out of level? How is this normally handled? It is a detatched garage. Thanks, Paul

[firewoodguy]

Quote: PaulS wrote on Wed, 13 February 2008 07:11

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---------------------------------------------------- Hi Paul, If the walls are being fasten to the slab is a poor policy if the garage is constructed with wood. The wood sills,base siding and lower parts of the wood studding will rot fast. The best way is to have a concrete footing below grade and have the concrete foundation set on the footing and have the concrete foundation extend above ground level about 12" or so then have your garage attached and fasten to the top of the concrete foundation. This will allow you to pour your concrete floor to have the 2" pitch. I have seen a thick concrete slabs poured level and install (one)concrete block on top of the slab all around the perimeter of the size of the garage and attached the gargae to the concrete bolck. Anyway, I would suggest before you do anything constructive, is to run this past your local build code department for his recommendations first. Good Luck

Firewoodguy.com

-- Firewoodguy

[Steve]

"PaulS" wrote on 13 Feb 2008 in group alt.building.construction:

There should be a level curb around the edge tall enough to get the siding at least six inches above grade. The sill plate will bolt to the curb.

Suggestion: If you're going to be parking cars in your garage (I know, it's a strange idea) have the concrete guy put a tire stop about four feet from the back wall. This is just a raised area that cues you not to drive into the back wall. If the building is to be used for a shop, keep the floor flat.

[Glenn]

Besides what has been said, 2" is a lot of fall. Put a car in neutral and leave it and you may find it has rolled out into the street.

[marson]

I don't necessarily disagree with the above--a row of cmu or a poured curb is a good thing. But if you are bolting walls directly to the slab, it will have to be framed so that the top plate is level. Not that big a deal for a good framer.

[DanG]

Normal pitch for exterior concrete is 1/4" per foot. If a garage is 20 to 24 feet deep, a 1/4 per foot would be 5 to 6 inches. The

2" fall is less than an 1/8th per foot. OP can run it dead level or slope the whole floor to a center drain for all I care, but let's keep the numbers in perspective.

[Erik Dillenkofer]

To answer the original question, slope the floor as called for, but pour a level curb the width of the walls to keep them level and square.

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[PaulS]

Thanks to all for your replies. I have heard of using a curb as well as a row of cmu to move everything up 8". My neighbor recently had a garage build on slab with a row of cmu. I will go over with a level and see if there is a pitch to the floor. I guess marson answered what was unclear to me. If the floor is pitched without a curb, the walls of the 3 sides would need to be adjusted for the pitch. That looks like a headache to me. I plan on building this thing myself and I don't consider myself a framer at all, just an old man who can follow instructions. So I will not try that. I will get the plan approved by the permit department, but I want to have a solid idea of exactly what I will do before meeting with them. I probably will pour the footing and walls, then the floor so I can get whatever pitch they tell me I need. Thanks, Paul

[marson]

Paul, if you are doing it yourself, you are right in not attempting to build a wall with a 2" taper. Also, the 2", while it sounds drastic, is marginal for drainage. If your garage is say 24', that is 1/12" per foot. That's marginal, and you WILL have birdbaths in that. !/4" per foot is usually recommended for drainage.

I suggest that a easier better way to go would be to install a trench drain in the center of where you park--the drain can just run to daylight anywhere convenient. Or you could skip the drainage altogether. Depends on how much water you expect.

[Rudy]

Thanks, Paul

Thats the normal way of doing it Paul. The 1/4" slope is generally for outside slabs. I found that 1/8" was adequate for the floor inside a garage, after all, what is going to run down the slope "inside" : a bucket of water spilled on the floor..some snowmelt off a car parked in a garage in Michigan ?

R

[Dioclese]

Go with the curb. A slanted frame job, exterior veneer would follow revealing the slant on the side walls on the first run.