Joined: July 2004
||Posted: 01 Nov. 2019,09:45
Permeable would be more expensive because of the additional excavation and aggregate build-up. However, as a 1:5 gradient, permeable paving would need special provisions to keep it functioning properly, and these would most likely boost costs even more.
You could go for a rigid option, but that, too, is relatively expensive (not as pricey as the permeable, mind) and needs a very high degree of skill to make it look good. There is far more of a challenge in rigid-laying block paving than in putting down a conventional build-up. If you choose this option, make sure you see the same type of work done by your selected contractor previously. I've looked at a few rigid-laid block pavements over the last couple of years and they've been a mess, because the contractor over-reached themselves. I would want to se a fully spec'ed job before giving the go-ahead.
The simplest choice is to rely on intermediate restraining courses, as mentioned in another thread a few days back. These are bands of kerb or blocks laid on concrete and haunched with same running transversely across the pavement to minimise creep down the slope and keep everything in place. There is a little additional cost, but nothing in the scale of your other two options. That would be my preferred option.
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