Concrete dust as bedding

[chequers]

Hi guys
I used sharp sand last time on the lower parts of the garden, now about to do the final area but can see that some are using Concrete dust 5mill down as a bedding
Would this be better on a domestic patio with a 6 to 1 mix than the sharp sand
I will need to slightly raise the bedding for the fall im thinking this would allow an extra 10mill or so over that sand from its strength

[r896neo]

Unless you use lots of plasticiser it makes a horrible unworkable mix.

Use the sharp sand again but if your bedding will be more than 60mm throw in some 10mm stone

[chequers]

Thanks sharp sand it will be
I also have got some flat block walls to get done can I use sharp sand or do I have to get building sand for this

[r896neo]

Get building sand, trying to lay blocks with a sharp sand mortar will break your heart.

If its very rough block on the flat then you might get away with it but it makes a very poor mortar with very bad workability compared to building sand.

[chequers]

Well it came down to two choices
A building sand which is the grittiest in this area or a fine plastering sand ,I went to three merchants to look at their sand so I guess this is the best I can do and it will have to do the patio and the wall
Thanks all