12 x 16 Shed foundation

[Sean]

I am planning on installing a 12 x 16 shed on a sloping site.  The low end of the site will be ~3 ft below the high end.  I am planning on using sonotubes but was not sure on what kind of spacing and diameter to go with.  Should I just use specs for decks - for example 3 tubes spaced at 8 ft and 2x8 joists spanning the 12 ft?

any input is appreciated....

[Amanda_931]

Check out John's little cabin.

http://www.jshow.com/y2k/listings/3.html

It's smaller and lighter than what you are planning, though.

Seems like one of the foundation pier sites does the math for you--big-foot ?.

Try this one--Footing Tube .pdf file.

http://www.foottube.com/FootingTube_Cat04.pdf