What Size Concrete Piers Do I Need

For sizing pier diameters for small foundations, the rule of thumb is “1 inch per foot of span.” Thus, a deck that spans 8 ft. will stand comfortably on 8-in. -diameter piers, while a deck that spans 10 ft. requires 10-in. -diameter piers.

What size pier do I need?

To determine the load of a deck pier, you must take half the length of the joist span multiplied by half the length of the beam span (measured from pier to pier). This number is then multiplied by 50, which is the 40 psf live load, 10 psf dead load mentioned earlier.

How many concrete piers do I need?

An 8 ft x 12 ft shed will need 6 piers, 3 per long side. What is this? Typically, the span between two piers is based on the dimensions of the beams and the joists. A double 2×8 beam should be supported every 4 to 6 feet.