855KG sand = 1m square ?

[Phil L]

Lay block paving....I put a 150mm layer of crush and run (MOT) all over, pack it down, then 50mm of sand, around here it's called Mersey grit (the Mersey is dredged every day so that container ships can use the docks) I calculate the area and divide by twenty for sand and divide by 6.6 for MOT...EG a 120m2 job will take 6 bags of sand and 18 MOT, although most jobs are usually around 40 - 50m2.

Recently I've been building extensions, this one is an extension to a shop,the shop is empty and has had the suspended floor removed. The extension floor had to be dug out to a depth of 750mm all over because the BCO didn't like the look of the infill, which looked to me like industrial waste (oily gravel and compacted ashes etc) We ordered 3 X 20 tonne loads for the extension, two of which were dragged in by the blokey with the mini digger, the third delivery went in by wheelbarrow and spade, we had about 8 tonne left and it went into the void in the shop floor, on top of this we ordered another 40 tonne and was about

4 tonne over, so the shop took about 44 tonnes, the extension about 52, all in all, 100 tonnes in 2 weeks!

theres a few pics here which I had to take for the BCO:

this one, the MOT is already about a foot deep and the second lot is going in)

is about the same stage, but a different elevation)

is after it was almost filled and whacked, although we have since put another 100mm on it)

You'll notice a yellow gas pipe in a few of them, we didn't damage this during excavation, nor filling back in, although we put a one inch hole in it a week later and the nice chap from Transco didn't charge us, put it down as a 'gardeneing accident', which saved us a couple of hundred.

[Andy Wade]

Solid or chippings? The density of solid stone will typically be in the range 2,000 - 2,500 kg/m^3, depending on what sort of stone it is, obviously.

OTOH 20 mm gravel or 10 mm pea shingle from a builders' merchant will weigh-in at more like 1,600 - 1,700 kg/m^3. By volume it's roughly 70% stone and 30% air.

That - ballast - will be denser since the sand fills the air gaps in the stone chippings. The density of sharp sand is similar to stone, so if you were to fill the 30% air gaps in the stone the density would increase by 30% to somewhere around 2200 kg/m^3. (And then, when making concrete you add cement to fill the gaps between the sand grains it gets denser still.)

Provided your heap is reasonably free-draining and doesn't get completely waterlogged, then whether it's wet or dry doesn't make a huge difference to the overall bulk density (at least not enough to worry about for ordinary building purposes).

Oh and a cubic metre of sharp sand weighs about 1,700 kg, not 850 and that's a fact.

[The Natural Philosopher]

Go and measure them exactly. They are not.

I use about 5 bags to do 50 sq meters and that was with aggregate as well - used 5 bags of that too, and cement, all to a depth of about 4 inches. (10cm) I make that 10 ton bags of muckite to do 5 cu meters..so about 1/2 cu meter per bag give or take.

it doesn't say

which is 0.72 cu meter if full, and they never are.

so I think we can let it lie that it's *about* a

Its nearer half a cu meter by my experience and reckoning.

- without delving further into the realms of

He will get 850kg dry weigh, give or take, and a little over 0.5 cu meter when properly settled down. If its sharp, it settles quite a lot under whacking etc.

reckons that a cu meter of compacted sand is 1.8 tons - that's 1632.93253 kg, or just shy of two bags.

I've never known that site, written by someone who has been years in the trade, be as wrong as you would like to make out

>

[The Natural Philosopher]

Not as true as you think. Gravel if whacked will compact down to have a remarkably high packing density. Over a couple of years the gravel on mny drive has squashed doiwn to about half its laid thickness. And yes, its on a hard syb base. Its all dwon to it getting moved by cars till it sedges up.

Probably comparable with the sand if its sharp. Soft sand has a more predictable, less variable packing density like all more or less spherical stuff.

The density of sharp sand is similar to stone, so if

Sharp sand IS stone, Sandstone to be precise. With bits of flint in - round here anyway.

Yup. That's more or less what everyone else says too, and it fits my experience. a bag of sand and a bag of gravel make about a cu meter of concrete TOGETHER..with about 6x25kg bags of cement (more if you want it stronger and less porous.

I don;t think this man here realizes how big a cubic meter is...when I emigrated fr a few years, I got everything I owned except the furniture in a 1.5 cu m container. Ok the loudspeakers had ornaments and books in them;-)

Or he fact that a 20% error in estimating linear dimension is a -50%

+100% error in estimating volume..weight and volume scale really fast with dimension..my 48" toy planes fly on 80W, but it takes a brake horsepower to fly a 96" one. and about 100bhp to fly a 50 foot span light plane >

[Andy Wade]

A pedantic point in this context but an imperial ton is approx. 1,016 kg[*], so 1.8 tons is more like 1,830 kilos. Where you got your conversion factor to 9 significant figures (8 of them wrong) I do not know, but it ain't right!

IOW the difference between and ton and a tonne is less then 2% and is seldom enough to worry about.

[*] An avoirdupois pound is /defined/ as 0.45359237 kg, so a ton is 2240 * 0.45359237 = 1016.0469088 kg

[Andy Wade]

True - although a compression factor of two sound a bit OTT.

Also true, although apart from the difference of scale the sand will be differently graded to include finer particles whereas the gravel (as supplied) will probably contain a smaller proportion of fine stuff.

For good concrete you need two of gravel to one of sand - usually as

1:2:4 (cement:sand:gravel) for a strong 'slab mix' or 1:3:6 for foundations. For a 1 tonne bag of gravel, half a tonne of sand, you'll need more like ten bags of cement for the 1:2:4 mix or 7 bags for 1:3:6.

Indeed so (well -49%/+73% actually). A metre's only about 9% more then a yard, but a cu. m is nearly 31% more than a cu. yard.

[The Natural Philosopher]

Google convert function.

Just typoe in 'convert 1.8 tons to kg'

Ah, it says 'shotrt tons' whatever those are. I didn't check..ah..a short ton is 2000lb.

Silly google.

its 16kg - a ton is 1016 kg.

[Phil L]

're made up to 1220mm cubed, although most are 900mm

You've just said even the smallest bags (90X90) contain almost 75% of a cube!

*compacted* is the operative word, it isn't delivered compacted, it's delivered very loose...I've no doubt my 50mm of sand when compacted is probably only 40mm deep, so 20m2 X 40mm would be closer to the mark of my original reply...and laying sand by the m2 of any depth is the same, no one mentioned how many metres they would get if it was mechanically compacted, for working out coverage of loose sand, there's a cube in the bags I get.

He's wrong on quite a few things actually, but not this one, you just misunderstand how sand is laid. I've nothing against pavingexpert, but his is just an opinion and a fancy website, it's not the rule of law