Concrete Shed base questions

[Rob]

Hi All,

I am laying down a concrete base for my 16' x 10' timber shed / workshop.

I have dug down 5 inches below ground level and am planning to lay:

4 inches of compacted hardcore A layer of sand Damp proof membrane Then 4 inches of concrete (so the concrete should finish about 3 inches above ground level.)

I have a few questions which I would be grateful if anyone can answer:-

1) Should I lay the form board / shuttering down before I lay the hardcore? (This means boards need to be about 8 inches high). Or should I lay the hardcore first, then 4 inch high boards (nailed to stakes driven into the ground). I am worried that if I put the boards down first, they may split when compacting the hard core with a whacker plate. 2) Is a 19mm thick board ok to use (for the shuttering) 3) What do I do with the damp proof membrane after the concrete has set - should I just cut the edge of it flush with the concrete?

Any help would be appreciated! Thanks, Rob

[The Natural Philosopher]

Make life easy. Use concrete blocks laid on a mortar bed over a bit of hardcore, on their sides below ground and up to damp and then use a DPC to mount the shed on. And some metal ties laid into the last course to screw into the timbers.