Slab is probably simplest. They use a lot of concrete which I would have had to take through the house so I put my office/shed on a grid of 12 concrete piers which the base frame sits on. Good for air flow too.
Yeah I was toying with concrete piers as they'll use less material and thus cost less. But I guess you need thicker floor joists so that might cancel out the money saving.
My floor joists were 75x50 I think (laid on short side obvs) which seemed adequate. I used builders buckets upside down with the bottom cut out as formes :-)
Slab is probably simplest. They use a lot of concrete which I would have had to take through the house so I put my office/shed on a grid of 12 concrete piers which the base frame sits on. Good for air flow too.