Is making your own Concrete blocks a good idea?

I have some largish DIY projects to do. I was planning on using 200mm* 200mm* 400mm Concrete blocks.
Firstly has any body got any idea what these would cost in fairly small quantities from a builder's merchant?

Secondly is it practical to try to mould your own?.
I've had a look for machines but they all seem far too big and expensive for my needs.

Is this a practical thing to attempt on a smallish scale?

Thanks in Advance.

Buy the block from the yard. The main cost will be the labor to mix the mortar and installing the block.

The most economic (cheap) buildings are made of block.

Cheers and good luck!

It's not really a practical proposition. Even if it costs you less, which I doubt, your time spent on acquiring materials, hiring a mixer etc would be better spent building with ready mades.
All the DIY stores sell them and in today's climate the Builder's Merchants may have some tempting deals. It's a matter of ringing round to get the best deal with delivery included. Consider aerated blocks if appropriate (Celcon, Thermalite, Durox) as although they are slightly dearer they are very easy to handle and cut.

There's nothing to stop you experimenting and making your own concrete blocks - to your own shape and size. You can buy ready mix concret in dry form from your such as B&Q and others.

This next should help you get started - a history of the readymix biz here in UK - from c1931. . . .

[PDF] The ready mixed concrete industry File Format: PDF/Adobe Acrobat - View as HTML
The supply of dry ingredients alone, even if premixed (eg in bags) to which ... but it was not until 1931 that the first ready mixed concrete plant was ...
http://www.competition-commission.org.uk...

not worth the bother, 100mm concrete blocks will cost around 80p to a pound each ( prices will vary according to quantity)If you want a thicker wall ,lay them on their sides for a 200mm wall. if blocks to be load-bearing or any height needed you should buy them ,ask your builders merchant for free advice

further to an earlier answer if you don't get all the air out, when the blocks get hot, the air expands and can split the blocks.

Realistically the time you will spend on this may not be worth the little you save. Especially if you get it wrong.

Although you could probably hire a machine from somewhere like HSS.

Good luck.

ok make some form work with timber.. calculate how many you want to make and add up the square metrage. order a concrete truck to deliver. also an mpa of the concrete is needed and the size of the rocks in it.. 20/20 is the norm for walkway and 25mpa is a normal strength i would think that would be all you needed. and hire a vibrator so you get a nice clean block.

no as these blocks are vibrated to make sure there is no air traped as it would weaken the block

I tried it twice, believe me or not it is not worth the mess!!!or maybe I was too fussy about that!!!

nope. if you dont do it right they will be brittle.

No,

Only if you want concrete blocks
Personally I have no use for them