Greenhouses, Sheds and Sun Rooms - 12x14 shed on concrete slab

I want to build a 12x14 backyard shed. I thought about a wooden floor, but after pricing the treated lumber, am thinking of pouring a pad instead.

My question is how much of a footing do I need for a shed this size, in our cold weather. I don't want the slab to crack with frost heave and throw the building out of square

I do not know the specifics for foundations in your area, but just a reminder to make the slab high enough above grade so the siding laps over the edge of the slab to prevent water from getting under the wall bottom plates, which need to be treated since they will be in contact with masonry.

My opinion is that you would be much better off using a stone base with a treated lumber deck.

First off, some building codes requires you to get a building permit for any structure with a foundation.

While at the same time, no one in my area sells metered cement anymore and the minimum amount of cement you can order is 4 yards and by the time they deliver it - you will have $800 into the floor by the time you dig your footings and build your forms.

Check with local building codes for the depth of the frost line in your area. In my area it is 34 inches deep. In Butte Montana it is something like 48 inches.

You could dig down 12 inches and put 8 inches of gravel base and then form it up and then put plastic on the bottom and pour 4 inches of cement. You wouldn't need to saw cut something that small as long as you used rebar and wire.

you should be able to use a floating slab. No need to get to frost line.