# What size footing do I need?

You can look up the recommended footing size, based on the size and type of house and the bearing capacity of the soil (see the table above). As you can see, heavy houses on weak soil need footings 2 feet wide or more. But the lightest buildings on the strongest soil require footings as narrow as 7 or 8 inches.

The rule-of-thumb is to use a tube diameter 3 times the post width, therefore use a 12” diameter Sonotube for a 4×4” post.

Beside above, how many footings do I need for a 10×10 deck? For our 12 x 12′ deck, we’ll use 12” round footings. Based on the dimensions in our example, the 12 x 12′ attached deck will need three 12” diameter footings, plus at least two more if you’re planning on building stairs.

Also question is, what size deck footings do I need?

Assuming a minimum soil bearing capacity of 1,500 psf, 8-inch-diameter concrete piers bearing on square footings measuring 2 feet on a side and 9 to 11 inches thick are adequate for most single-story decks where beams are spaced 14 feet apart or less and joist spans are 14 feet or less (see table below).

How deep should a column footing be?

A guideline for the depth is 12 inches, plus one additional inch for every three inches of the column. For example, the footing for a six-inch column should be at least 14 inches deep.

### How many footings do I need for a shed?

Typically, most sheds will need four posts, located near, but not necessarily at, each corner of the building. Larger buildings may require more, depending on the span and the amount of weight to support.

### Do you leave sonotube in ground?

No, it’s not a problem to leave the Sonotube and its plastic “Square Foot” (like these) in the ground forever. Although they will slightly retard the hydration (loss of water) of the concrete mix, the concrete will achieve enough strength in a few days to build upon.

### Do you need rebar in sonotube?

To support a beam for a residential deck, does a Sonotube pier need any rebar? A. We usually recommend that a minimum of two pieces of #4 rebar be placed vertically in an 8-inch-diameter concrete pier supporting a structure. A larger-diameter pier should have four or more pieces of vertical rebar.

### How much concrete do I need for a sonotube?

For example, a sono tube with a 10″ diameter and a 4′ depth requires 0.08 cubic yards of concrete.

### How many bags of concrete is in a yard?

To determine how many bags of concrete you will need, divide the total cubic yards needed by the yield. Use the following yields per each bag size: 40 pound bag yields .011 cubic yards. 60 pound bag yields .017 cubic yards.

### Can sonotube get wet?

Sonotube forms should not be used in standing water. However, Sonoco’s patented RainGuard® technology allows Sonotube concrete forms to withstand wet weather conditions for up to 24 hours. For maximum strength, Sonotube Commercial concrete forms can withstand wet weather for up to 72 hours.

### How wide should a hole be for a 6×6 post?

The depth of your hole should be about 1/4 of the height of your post. For a 6×6 post, the diameter of the holes should be about 12 inches square. As a rule the width of your post hole should never be less than 10 inches. You want holes deep and wide enough to easily support a standard 4×4 post.

### How much weight can a concrete pier hold?

Multiply 36 by the total load 50 = 1800 pounds. Using the examples, pier (a) is holding a total load of 900 pounds while pier (b) is carrying a total load of 1,800 pounds. Once the total load of each pier has been calculated, it is time to determine what size pier is needed.

### How deep and wide do footings need to be?

Depth: Footings should extend to a minimum depth of 12 inches below previously undisturbed soil. Footings also must extend at least 12 inches below the frost line (the depth to which the ground freezes in winter) or must be frost-protected. Width: Footings should have a minimum width of 12 inches.