No one with any knowledge of soils would advise using sand to "break up" any soil. What are you trying to accomplish? What do you mean by "break up" that soil? What kind of soil do you have, clay, sand, or something else?

If that soil is clay then what it needs, most likely, is organic matter, not sand. If that soil is sand why would adding more make it better?

Sorry my bad, I was relaying the question from my mum and got mixed up.

Basically we bought a Japanese maple yesterday. It's in a small pot and we would like to re-pot it into a bigger pot. So we usually do that standard repotting procedure by putting stones at the bottom and mixing compost with sand. Both the sand and the stones are to help with soil drainage. And that is what we were wondering. Can we use regular builder's sand for repotting?

I am assuming you are located in the UK and if so, some of your terminology is different. Like 'compost' for 'potting soil' :-) That part's fine but don't add sand.....see if you can find perlite or pumice instead. Builders sand is just not coarse enough and doesn't add anything to drainage. Neither do a layer of rocks or gravel at the bottom - in fact, they actually slow drainage and raise the perched water table.

And if you intend to grow your maple in a container long term, you might want to visit the Maples or Container Gardening forums for discussions on a much better soil mix to use for containerized trees and shrubs. This forum really focuses on inground plantings :-))

BTW, washed sand should not have any kind of harmful chemicals in it. There is some risk from silica DUST causing lung problems if you are exposed frequently over a long period (such as in the mining industry). As a result some governments - such as the State of California in the US - require labeling bagged sand as 'contains chemicals known to cause cancer'. Bit of a stretch in my opinion. But it's not added chemicals, it's the sand itself.

Ricardo, just take yourself to a garden centre and buy a bag of ready made John Innes no. 3. potting compost. That's the one you want for shrubs which will be in containers for a long time. Save yourself the hassle of mixing your own potting compost. John Innes composts explained.