On 8/4/2013 3:11 PM, MJ wrote:
In a week, I'll be building a 10x12 shed.

The plans call for a on-grade foundation with 6x6 skids. My property is sloped. From high pt to low pt is about 8 inches. I called out a guy and asked about pouring a slab. After I got over the price objections ($3k), he and I talked about cheaper suggestions. He said, oh, we could do Sonotube piers. I agreed but the project at that point stalled as I lost the person who was going to help.

Anyways, I found another person and he said he and I would do the foundation layout, digging, etc. ourselves. I told him my soil is kinda hard (clay and possible sandstone). No problem, just water the area and it will soften. I did a test dig yesterday and the water didn't drain for over an hour. Hmm, this is gonna be tough going.

Here's where I'm at. I could go with on-grade foundation using solid concrete blocks to level up the low spots. Not a problem for me, easy to layout and make happen. Or... we could get a power auger and drill the Sonotube piers. My helper who is a expert carpenter is away on vacation until two days before we start, so I can't get his opinion.

Which way would you go? Block or tubes?

My only concern is earth movement. Earthquakes are possibility. But a rare one. Would one would see a wood foundation come off a cement block pier in a minor (less then Richter 2) quake? I thought of drilling into the block and holding the joists with anchors. Can you drill solid block?

MJ

Two years ago I had a 10 X 12 shed built for lawn equipment. It is
built on a 2 X 6 floor with 2 X 6 on 16 inch centers. It was leveled on
blocks. (20 miles east of Raleigh NC in a rural area)

While there has been a lot of good advice, the one thing that must be
consider when building are the building requirements for the community
you live. In this area there are no building requirements or permits
required if the building is 120 square feet or less. If I had run fixed
electricity to the shed I would have been required to get a permit.

Depending on the area they may have unique ideas on how sheds are
constructed including the foundations they are built on.

There is another considerations. While others have made comments on
what they have in their sheds, I don't believe you said how you were
going to use yours. If you have a lot of heavy equipment table saws
drill press,grinders, etc, with a lot of vibration I am not sure I
would consider blocks. Though you would not believe what some people
consider foundations for houses. Some of the old houses in the south
are built on a pile of stones. You wonder how they still are together
after 100 years. Some look like removing one stone would bring the
whole house down.