[BJR]

A little.

The dearer pavers are the large format concrete pavers. 2ft x 2ft. they are almost 2x the price of a clay paver, and becoming more popular in courtyards.

Clay is definately a better product as far as wear and keeping clean, but vary in size a bit more.

Concrete is more uniform, but harder to keep clean.

What size stone base do you use?

It has do be at least 20mm minus. Sorry for the metric.

If you are using say 7mm minus, the base will not be as strong for vehicular trafic. As mentioned in a previous thread I knew a contractor many years ago that did it (from what I can gather) your way and all of his drives eventually failed because of it. They all got divets where the tyres went.

Are your roadbases (stone) in different quality gradings? We have many gradings and the one we use for vehicular pavements is a BGB20. Which, I'm certain, stands for 'Designated Graded Base 20mm minus'. This is what is used to construct roads. It is graded to a formula of particle sizes so that when compaction happens it is void of any air pockets which impedes moisture penetration. Once compacted with the correct moisture content you have to use a jack hammer or a machine to break it up.

[Stonehenge]

20mm is about 3/4 inch (3/4"), and that sounds about right.

For vehicular pavements we use a 3/4"- crushed stone for our base. We install it in lifts of 2-3", with a total thickness of about 9" for that stone, with another inch or so of what you'd call 7mm-. No sand.

Though actually, since last year we've changed our base prep for vehicular traffic - was sub the base prep to an asphalt paving company, where they prep the base as they would for vehicular traffic (7-8"(200mm) of 3/4"-). Then 2"(50mm) if asphalt binder course. Binder course is regular asphalt, but with much larger stones in it - it's much more durable, but less attractive.

Once the asphalt is installed, we come in and screed 3/4" coarse sand over the asphalt, then lay the pavers. From what I've seen so far, it gives a much firmer pavement then what we've done using our old method.

But that's just for vehicular traffic. Pedestrian traffic we use 6-7"(150-180mm) of screenings (~ 7mm-) as the base.

The results of the test we're conducting will determine if we continue using that method.