Hi all, hardcore thickness?

[loiner]

I'm about to lay a patio, and am unsure of the hardcore thickness and how to work out the amount of sand/cement needed. the area of the patio is approx 3m X 4.5m...all help gratefully received.
Also is it advisable to use Breeze block for a retaining wall or should I stick with bricks?

 

[bhwh]

Don't know if you've checked out www.pavingexpert.com or not but all your answers will be well documented there.

Try this page:

http://www.pavingexpert.com/subbase.htm