A fall of one in eighty, and always away from the building
The fall
About twelve millimetres of drop per metre, running away from any building. Set a string line before laying anything and check it constantly.
The level below the damp course
Paving must finish at least a hundred and fifty millimetres below the damp proof course. Above it, water bridges into the wall.
The base
A hundred millimetres of compacted hardcore under a sand and cement bed. Skimping here is why paving sinks in year three.
