buy by weight, use by volume ?

[simonsmith.uk]

just pricing up a job at home, its a bit of decking in the back yard surrounded by a "moat" of gravel.

She's not decided on which gravel yet, but I notice its sold by weight, where I have no idea how much I need by weight, but can work out the volume of the area to fill .

Q. whats the best way to work out how much gravel I need ? I dont want to over buy and have the stuff piled up everywhere

I see a couple of possibles

1) buy in two loads , (double delivery costs) ! 2) buy a small bag and weigh / measure it (the final gravel may be slightly different (dryer etc) ) 3) guess

What do other people do ?

[Andy Wade]

If you assume the density is about 1700-1800 kg/m^3 you won't be too far out. Actually most builders' merchants will accept orders by either mass or volume, IME.

[TMC]

Ask the builders merchant what the volume to weight ratio is or if buying prebagged from the sheds measure the length width and thickness of a bag and do the maths I have used both methods and they worked fine but note that if buying loose you may need to go to the nearest 1/2 ton

Tony

[TonyK]

Very rough guide I have sucessfully used several times is 1 metric ton per cubic metre for loose chippings.

[Huge]

Agreed. That's the density I use, also.

[Roger]

The message from Huge contains these words:

I think somewhere inbetween that and the figure Andy suggested. My ancient source of information gives the amount of gravel to make a cubic yard of (1:2:3) concrete as .794 tons or .748 cubic yards. Translating both into metric gives .807 and .572 which gives a relative density of

1.4 if I have my sums right.

[Tony Polson]

Most stone commonly used in building has a solid density of approximately 2.7 tonnes per cubic metre. Single size chippings have a porosity (percentage volume of air) of approximately 40%, meaning that approximately 60% of the volume is solid rock.

So the bulk density of chippings is approximately 60% of 2.7 tonnes per cubic metre, which is 1.62 tonnes per cubic metre. If compacted, the density will rise beyond that figure.

Graded stone, consisting of a mixture of sizes from sand through to gravel-sized lumps, has a much lower porosity because the small pieces fill up the holes between the larger pieces. Typically, the compacted density of graded material will therefore be around 2.0 to 2.2 tonnes per cubic metre.

[The Medway Handyman]

Try

they have some accurate figures on gravel coverage.

My only experience is with 18mm gravel, 2 tonnes of which covers 4m x 4m x

50mm deep.

[somebody]

In message , [e-mail] writes

A handy site....

hth Someone

[Bob Mannix]

I can verufy that from a local sand&gravel quarry where I asked the question. They said 1m^3 of 20mm shingle was 1.56tonne which compares well with the dry gravel figure on the site.