Joined: July 2004
||Posted: 28 Sep. 2012,09:11
Permeable block paving (CBPP) just hasn't taken off for residential driveways, despite all the bullish predictions from the manufacturers back in 2008 when the comedy legislation was launched' because there are significantly cheaper ways of achiveing the same result.
If you take the average British driveway, which is 48.5m², why would you excavate to, say, 450mm and generate and additional 14m³ of spoil (two good wagon loads) when you could drain the lot to a 2m³ soakaway? It's economic and logistical madness!
Slightly different scenario on commercial schemes, where the case for CBPP is much stronger, and I get angry when I see brand new commercial parking areas, such as the two bloody huge new supermarkets built in nearby Leigh in the last 12 months, being surfaced with blacktop. Firstly, what sort of corrupt planning scheme allows an impermeable surface to be specified on such large and low-lying areas within a known flood plain, and secondly, why are the economics so skewed to favour impermeable paving? There should be financial incentives, whether it's via tax advantages or punitive planning charges, that make permeable paving (and I'm quite happy to see permeable blacktop, if that's what designers prefer) the default surface of choice.
Returning to the residential market, I've been out to assess four so-called CBPP installations this year and in every case, the contractor didn't have a chuffing clue what they were doing, ranging from the pillocks in Warrington who used crudely broken 3x2s as a sub-base to the moron in Chadderton who used at least 20 bags of KDS on a 40m² CBPP driveway. Now, we all know there are contractors out there who *do* know how to do the job, but they are then pricing the work accurately, whereas these eejits have no understanding of the procedure and materials, and are consequently under-pricing the job and winning the work on cost alone.
Finally: rainwater harvesting. It may seem like a crazy idea to us in the north and west of these islands, Pablo, but it's of HUGE interest in the chalk areas of Lower Britain where hosepipe bans and parchged summers are the norm for many and the opportunity to have their own private supply of water for the garden and/or washing the car, is highly attractive.
I designed a RWH scheme in Kent where the property owner had a 1 acre small holding that was slowly dtying due to the hosepipe ban. Installing a harvesting system for the 80m² roof and 140m² driveway now provides just about enough water to get them through a normal summer. It cost roughly 8,000 quid extra for the tank and the pump and the pipework, but the client considers that to be excellent valuie as it means the smallholding and garden thrive, his metered water bills are reduced, and he's looking at a service life of at least 25 years. If growing veg, keeping chickens and ponies, and having a stunning garden were your hobby, would 320 quid/year (8,000 ÷ 25) or less than a pound per day seem like money well spent?
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