Weight of Decorative Chippings Needed?

macman

I want to order some of the above for a garden refurb, but unsure how to calculate the volume/weight required.
I'm looking for plum slate chippings, 40mm. The area to be covered is 8.5 sq m, required depth 50mm (about 2 ins).
Some sites say need 1 sq m of these will require 38kg, but this is only to a depth of 1 in. So based on 2 ins depth, do I need 72kg per sq m, so 72x8.5=612kg in total?
If so, is is better to go for a bulk bag delivery (most of which seem to be around 800kg)?

macka0

get a tonne delivered ...you should need just under that amount bout .8 but just spread it out

27col

As above. You will soon disperse any surplus when you spread the chippings out.

macman

I can't spread it out any wider, as the area is surrounded by paving/walling. So if I need around 800kg, the basic figure is about 94kg per sq m.?
The coverage seems to vary enormously depending on which supplier's figures you believe, so looks like I'd better go for an 800kg bulk bag.

macka0

you may not be able to go wider...but you can go thicker

macman

Not unless I dig it out more...the first 2 ins was enough work!
Not really a problem as I can use it elsewhere or donate to neighbours.