The Brew Cabin

We are building a large patio area in our garden and two elements are going to be a 12 foot (approx) circle and a 9 foot circle. We have purchased two pallets of clay cobbles manufactured by Marshalls, coloured Shelbourne red. These cobbles are supplied in sets of 8 moulded together which need to be split by hand (or more importantly by hammer and large chisel) and I therefore have a three foot high pile of many thousands of these little monsters (all slightly different but pretty much like 2.5 inch cubes) all waiting to be laid. We have excavated and flattened a large enough area and have laid a 2 to 3 inch base of hardcore in the shapes required. I have then laid a one to two inch carpet of rough sand as the base on top of the hardcore.

And now is when I am seeking important advice…What do I do next?

1) Should I start at the middle and just do one ring at a time? Or should I start at the outside and work into the middle?
2)Should I lay all the cobbles before using a vibration plate to level these? Or should I lay a small section at a time and use the plate a little bit at a time?
3)Will the cobbles sink down by much when the plate has been used?
4)Do I need to use a special light vibration plate? I’m worried about crushing the cobbles.
5)How do I secure the outside rows of cobbles so that they don’t move? Do I need to cement or concrete these in? If I cement them in, and work from the outside in, do I therefore need to lay the inside cobbles an inch higher to compensate for the lowering caused by the vibration plate?

I would appreciate any advice or insight you can offer.

I have those "little monsters" in my garden - they make great features and look very 'cottagey' which is the style I wanted.

1 - start in the middle and work outwards.

2 - Lay all the cobbles before compacting. Worrk on a pre-compacted bed, as described on the Screeding page.

3 - Yes - about 5-7mm, if you use a pre-compacted bed.

4 - No - a standard vib plate is fine. Those little cobbles are a lot tougher than you think!

5 - Lay the two outermost courtses on a bed of concrete, and then haunch the outside edge. When you lay these courses, tap them down to final level, so that they are actually 5mm or so lower than the inner courses. Give the concrete 24 hours to cure, and then you can vibrate the inner courses.

HTH