Footer

deere2440 · 03-01-2008, 04:15 PM

I have a concrete question. I am building a garage that is 30x40 with 9' walls. I want to pour a footer, then pour the floor inside of the footer, then attach the walls directly to the footer. How wide and deep does the footer NEED to be to be built right.

nap · 03-01-2008, 05:52 PM

You will most likely need to consult the local building department to be sure you build according to local code.

There are standards but each jusrisdiction can enforce their own requirements.

deere2440 · 03-01-2008, 06:43 PM

My local building company suggest a footer 30" deep to get below the frost line and when I said a foot wide they said that would be plenty. I just want to know if that is minimum or the right way.

nap · 03-01-2008, 07:20 PM

well, depth is dependent upon your freeze line so you are in a better place to make that call than those here without additiaonl info.

as to the width, a foot would typically be fine but I suggest you check these dimensions with the local building department.

as well, the footer does not need to extend all the way to the surface. I can be at the needed depth and the thickness, again, should be checked with the local building department, and then the width can be reduced to the wall width above that.

**AtlanticWBConst.** · 03-01-2008, 07:23 PM

Follow Nap's advise and check with your local inspectional services/building dept.

deere2440 · 03-01-2008, 08:27 PM

My freeze line is 30 inches. I was told that by a local contractor. I was planing on pouring the footer 30 inches deep and 5 inches above the ground. Then pour the floor inside till level. Attach the walls directly to the footer. But I am by far not an expert so is that a big mistake?

Chris Johnson · 03-01-2008, 09:38 PM

Save yourself some money and pour the footing @ the 30" depth to be below frost, the width and thickness is a local call, if 12" is fine for the width as suggested by the building department, then go with it, now find out the depth or thickness from them. Once complete build a stem wall from the footing to a predetermined point above final grade, this could be six inches, could be eight, it is a local building department call. Stem wall can be CMU, Pour in place, or even ICF if you wish.

The stem wall can be narrower then the footing, saving you concrete which is expensive. Pour your slab afterwards and but up against the stem wall. If it's a garage you are going to need slope from back to front to allow water to run out, don't pour it flat.

concretemasonry · 03-01-2008, 09:54 PM

Definitely bring the block stem wall above grade and make sure you have a minimum of 8" above the planned floor level.

Pour the floating slab on compacted soil and do not attach the the block stem wall.

You will appreciate the 8" of exposed block since it will get the wood framing well above the winter slop and moisture and will be much easier to clean. - You will also get a little more headroom inside.