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?


Well, you could use gravel or crushed limestone to level in the areas for
the blocks, or to lay your 6x6 right on. Just be sure to compact it well
before building on the fill. If you compact it well, it will hold for
decades.

--

-Mike-