Hi,

Fairly sure I know this - but just want to get my facts straight:

Whats the minimum acceptable depth for a bit of concrete poured onto the
earth (with a DPM), for a room thats about 1m x 2.5m?

I thought it was about 100mm.

Having removed some shuttering today, I discovered the builders had a
managed to get as thin as 50mm.

And they "forgot" to blind the ground with sand - the DPM sheet is sitting
on pointy rocks. The reason I know this is I asked for a channel to be left
for me to fit a channel drain, aka:

http://photos.dionic.net/v/public/bu..._0009.jpg.html

I'm pretty sure I'm going to be telling them to get back pronto and do it
again (for free) but I just wanted to be sure I wasn't being unreasonable.

Sigh.

They did OK with most of the fiddly bits, because I was specify like a
government department, and checking regularly.

I relaxed with the floor slab, because "builders know how to do floor slabs"
All I said was do it to building regs and leave 100mm above for me to add
insulation and screed with UFH. Sounded simple enough...

Makes me feel totally justified in DIYing 90% of the project - rather
wishing I'd made it 95%!

And these are not "rip off dudes" - they're known to me and generally
pleasant and helpful. Just seems that anything to do with floors given them
the wobbles.

Cheers

Tim