Absolutely not, no. Unwashed builders sand contains lime and salts, but even were it washed, that type of sand does nothing at all for clay soil, in fact, if anything, makes it worse. Add horticultural grit or washed fine grit instead, along with as much humus rich material as you can afford (garden compost, composted animal manure, leaf mould, anything like that).

Spent mushroom compost is good too.

i have used it without noticing any difference , i have also used beach sand too, it has helped loosen heavy clay soil , but as above the best thing is organic matter.

Do NOT use beach sand! Full of salt...

Also it is illegal to remove sand from a beach!

I disagree about builders sand containing lime and salts Bamboo. It does contain a small amount of lime, but NO salts.

Sand for construction use needs to conform to strict regulations regarding what it contains and it's regularly tested to make sure it meets the standards. Imagine if a tall concrete skyscraper was built using sand that contained impurities. The structure could be weakened and the consequences could be disastrous. For this reason sand for building use is not taken from the beaches because it contains salt. It is mined from quarries or dredged from rivers.

I regularly use sharp sand, which is mined from quarries and is gritty, as opposed to river sand (soft sand) that is more rounded, to use as a mixture in pots as I believe it's as good, if not better than horticultural sand. In my opinion, apart from builders sand is about a third the price of horticultural sand the only other difference is that horticultural sand is usually kiln dried, which doesn't make any sense to me as it's going to be added to wet soil anyway.

However, I do agree that adding sand to clay soil to break it up is not the ideal thing to add and garden compost, mulch or manure works better. Having said that, sand can be used to break up the clay and improve drainage, but you would need a large amount to do this, probably a ratio of about 1 part soil to 2 parts sand or even more.

In my opinion, use compost, mulch or any other suitable quick degrading vegetation. If you have some builders sand to hand that you want to dispose of then add this to the mix. It won't harm it and I think a bag or two of builders sand is a good thing to keep to hand if you want to make certain John Inness compost rather than buying it in bags.

I was visiting what was then known as Leningrad and I noticed that their residential high rises were crumbling and flaking. Asking about this I was told that they had used concrete which was made with sand which contained salt. I doubt that those buildings are still standing today.

A similar thing happened in China 11 years ago. A lot of people were killed or injured. The persons responsible for passing off the dodgy sand are still in jail and will be for a long time to come.

I sometimes think that building materials are more rigorously inspected than the food we eat.

I an in the 'yes' camp. This is a regular question. Soft sand is the one to avoid as it will do the reverse and clog soil particles. It is sharp sand that you can use although it does contain chalky particles which can be a problem if you grow lime-haters. It can contain a little salt which you could wash if you are concerned. Horticultural sharp sand is at a premium price as it contains no chalk. Silver sand is the finest of all and was, at one time used in potting composts.

Overwintering will wash out salts from sand. Along with soil nutrients. That's why we fertilise every year, and why organic nutrients are better as opposed to inorganic.

Be careful with spent mushroom compost as it is highly alkaline and regular use can cause problems.

remember the only people to escape from Alcatraz ? this happened because they used the sea water too get rid of waste,washing etc . it degrades cement and makes it soft as Myron sais. wear I go to get my tropical fish sometimes near the marine section he has to keep re skimming the cement on the floor .

If you are in any doubt, put the sand in a large container and run water through it using a hosepipe. Stir the sand about and let the water run over the top of the container. This will wash all the impurities out.

Done a bit more research - provided you're sure your sand isn't over limey (if your soil is already alkaline) and you've flushed out salts, either by overwintering outside in the open, or washing it yourself (good luck with that), you can add it to clay soil AS LONG as you add an equal weight and volume of organic material (the aforesaid composts), with the sand going down first, then a week or so later, the organic material, and then dug over. You may then want to check the soil ph before planting. If you are going to do this form of amendment, it needs to be done in a large area, not just a small one, otherwise, anything you plant in the amended area, once it hits the solid clay further out, will suffer.