[mushroom]

I'm doing a foundation for the shed, when it comes, this weekend. Just using 15 or so 400mm square flags, laid on top of builders sand. Which is laid on top of soil.

1. should I mix some dry cement with the sand?
2. should I put some permanent systematic weedkiller (like the stuff you'd use on drives or between concrete paths) on the soil before laying the sand down?

[new_2_veg]

some cement mixed in will stop the sand washing out, i done mine like that and its held nice and ferm

nathan

[bikerjohn]

If you don't use a sand/cement mix, and only use sand on soil, you run the risk of the base sinking and becoming uneven.  Firstly, pun the soil down on the area of the base so it's nice and firm.  Then use a 5:1 mix of coarse sharp sand and cement, damped but not soaked, and lay the flags on this.  The sand/cement mix will then dry out in a day or two, and you will have a solid base that shouldn't sink.  
Best of luck.
John.