Three by three metres; roughly 100 square feet.
Concrete pad seems like an awful lot of work and a very heavy installation?
More like something one would install for a small very robust building in
which to house a diesel generator at a radio site?
I'm just thinking that one can buy, just for example, an 8 by 12 foot shed
kit that requires anywhere from six to sixteen treated wooden or concrete
posts poured into those cardboard tubes, depending on what load one needs to
put on it's floor! Such sheds, starting at around $1800 Canadian (say 800
quid) or less can be simple storage units or can be dressed up with rustic
siding, extra windows, half (stable style) doors, skylights etc. Also
available up to 14 by 20 or longer (I was considering one 14 by 24 as a
second garage. Substantial posts every four feet, vehicle weighing about
3500 pounds plus tools work bench etc.
Sheds mounted on short posts above ground allow ventilation below, and raise
the floor a little above a small amount of snow. With typical maintenance
they last 30 to 40 years. They also can be given the same exterior finish
and/or painted to match the main house.
Because of frost heaving we have to go at least 30 inches down. With a
manual post hole digger, and a digging bar in our stony/rocky ground one can
dig a hole in about twenty minutes, with suitable tea breaks! We have two
such home built sheds in which we store lawnmower, snowblower, extra sets of
winter wheels and tyres for several vehicles, garden tools, a 2000 watt
standby generator, spare flower pots, spare gasoline (away from the house)
and other useful junk! One 8 by 8 foot shed is on four posts and is 20+
years old and the other about 4 years is on six posts. I may move the 8 by
8 to another location by cutting off the 4 x 4 inch treated posts and towing
it within the garden with our pickup truck; to make space for the proposed
14 by 24 unit.