Carpet stones

[JCP]

Hi,

First time poster and regular have a go D-I-Y'er.

I am laying a patio area where lawn used to be.

So far I have dug out, compacted and levelled the area to be paved and lovingly broken up stones and bricks to form a hardcore layer of about 2 inches thick which I've yet to compact. The area to be paved is only 3m x 3m and I am using Random Carpet Stones on order from Bradstones.
Their guide suggests a base of 6 parts sharp sand : 1 part cement but they seem to be working on a base without hardcore. (I'd already laid the hardcore before finding out that I didn't need a solid cement base).They state that the sand/cement layer should be 75mm thick. Can you tell me, would this 75mm still be necessary as I have laid the hardcore already and, are there any pitfuls you feel I should be aware of with this style of paving ?

Any help is gratefully received.

JCP

[Tony McC]

Broken stones and bricks - luvverly!

There will be so many voids in what you refer to as 'hardcore' that you will definitely need the 75mm of concrete or sand/cement. Broken bricks and stones are more trouble than they're worth - they do not give you a proper sub-base. What they do give you is a void-ridden layer of crap that needs to be stabilised.

Make a dry mix of grit sand with cement, roughly 8:1 or a bit stronger, and spread it over that rubbish you've put there. Use a stiff brush to try and persuade it into the voids, and then run a vibrating plate compactor over the lot to rattle it down into all those empty speaces. Repeat until the voids are filled and no further sand+cement can be forced into the rubble.

The Carpet Stones can be laid on 30-50mm of a fine concrete. Use summat like 4 parts 6-10mm gravel to 2 parts grit sand to 1 part cement. Trample this with your boots, screed it to level, and lay the Carpet Stones as recommended by Bradstone.

The jointing will be a problem whatever you do. If this is a pedestrian area, a sand or weak sand-cement mix will be the best option, but be prepared to toip it up at regular intervals.

[JCP]

Knew I should have gone on the net first, I might have found your site before starting and saved a load of time.

As this is only a small area I can easily take up the stones and bricks as they are small pieces, about an inch by an inch, so can be shovelled up, I only laid it because I thought "that's what you were supposed to do"

I want to do this properly so assuming I take up the bricks and stones and get back to my nice level and compact soil, what do I need to lay on to the soil to get me going or is that what you've already covered in the last post. Sorry to be a pain but I've clearly cocked this up once already.

JCP

[Tony McC]

If there is soil present, ie proper topsoil, then this should be skimmed off and the level reduced to a hard sub-soil or clay is exposed. If this is not likely, then use a geo-textile membrane beneath the sub-base material to prevent it mixing with the soil.

See the sub-bases page for more info