Paving a former vegetable garden in italy

[zen00zero]

I am delighted to have found this site!

We live in an appartment in the centre of Rome and have a small plot - 600 sq m of weeds with a tin hut on it in - in the country an hour's drive to the North.

Recently, we bought an ancient caravanette that we plan to keep on our plot. The van's gross weight is 2500kg.

The plot is reached by a narrow dirt track about 200m from the sealed road. Nothing wider than 2m can use the track.

I want to pave over an area, previously used for growing tomatoes on which to park the van and turn it round.

I reckon I'll need to pave an area 8m x 8m. I plan to use the locally abundant tuff stone blocks for the surface, with wide gaps (circa 5cm) to allow grass and herbs to grow between them.

The soil is a strange mixture of clay and sand, which sets like concrete when it is dry but drains well. It is the exposed bed of a lake whose shore is now 500m downhill in a volcanic crater. It is also infested with perennial weeds such as ground elder whose roots are more than 30cm deep and which no amount of digging has been able to eradicate. I have been regularly parking my car on an adjacent piece of ground for years without any problems.

It almost never rains between May and September and the ground becomes parched. The rest of the year has a fairly reqular cycle of rain or snow and fine weather. There are frequent very heavy downpours when surface water can be a problem. Frost is rare.

My basic plan is to mark out and level the area to be paved without removing the topsoil, compact the soil with a vibrating plate, spread and compact 2 layers of sub-base using demolition waste, cover this with an appropriate thickness of sand and then lay the tuff blocks, and fill the gaps with a mixture of soil and sand.

I am quite happy about the paved surface being higher than the surrounding ground.

My questions:
Is it sufficient to compact the topsoil and use this as a sub grade?
Should I lay a membrane between the sub-base and the sand?
Should I lay drainage tubes in the soil before spreading the sub grade? These would be run to an existing ditch.

Demolition rubble - this is a readily available and free material in Rome (contractors usually have to pay to get rid of it), resulting from appartment rennovations. It consists of broken lightweight clay bricks, plaster, mortar and hard floor materials such as marble, broken ceramic tiles and cement mortar sub-floor rubble. Would this be OK for a sub base?

Getting material to the site is also going to be a problem which I think can only be resolved with a wheelbarrow and a lot of hard work.

[GB_Groundworks]

to address one of your problems quickly i'd hire either a tracked mini dumper/barrow 400kg capacity or a 1 to 3 ton dumper for a day and move all your materials that way, for the 80 or so euros it will cost it will be worth it. alternatively find a local farmer/builder and cross his palm with some vino tokens and get him to shift the stuff save your back. you'll have to organise it so they get dropped off by the road etc.

[lutonlagerlout]

you really should read the main site :;):
laying old bits of stone on sand on rubble on topsoil will fail quickly
LLL

[Tony McC]

Topsoil is bad news: by definition it contains a high percentage of organic material that *will* decompose over time and thereby reduce its volume, resulting in settlement. However, given the rough-n-ready approach to this pavement, that might not be too big a problem.

Rubble as sub-base: again, a potential problem as you have no control over the void content. Genuine sub-base material is carefully designed to control void space and achieve a predictable degree of compaction. Rubble can never, ever do this unless it contains sufficient fines. It may be necessary to lay, say, 50-70mm of rubble then blind with coarse sand before compacting and placing subsequent layers.

Membrane: this largely follows on from the above. If there is a real risk of losing laying course material due to trickle-down, then a membrane would make sense, but it MUST be the right type of membrane. A landscape fabric is NOT strong enough: it must be a construction geo-textile.

Drainage tubes: do you mean pipes? If so, they would need to be rigid (clayware or concrete), and not flexible otherwise they will simply collapse under the weight of the pavement and its traffic, but if, as you say, the ground is naturally free-draining, why would they be needed?

Finally, the jointing would concern me. You are planning to use wide joints, which virtually eliminates horizontal (rotational) interlock. I can't see how a mix of sand and soil would help keep those blocks in place.