Zipadee Doodar wrote:
I inted to lay decking over a tatty concrete area at side of house.
What is the minimum depth of joist to use? I want to keep the
increase in floor height to a minimum. Would I get away with
something like 2 x 2 inch joists laid on thin roof slates to raise
and level them over the concrete like this....

====================== deck board
[ ] 16in [ ] 16in [ ] 2 inch joists
== == == slate / tile leveller
/////////////////////////////////////////////////// concrete base

or is this a recipe for a quick (though short) descent?
I built a ground level deck a few months ago with 2x3" joists.
Its fine. I reckon I could have got away with 2x2"
I see also that the pre-cut decking kits that B&Q and Wickes sell use
70x70mm frames