SUSTAINABILITY
PAVING THE WAY SUSTAINABLY
A new driveway, provided it uses the right materials, can make a significant contribution to a household’s sustainable credentials. BMJ looks at how merchants can advise on planning permission pitfalls that can risk the completion of a project.
E
ven the humble driveway has been influenced by the change in government building policy over the past decade, coupled with more people wanting
sustainable solutions in their daily lives and a growing desire and trend for off-road parking. These different aspects have led to
numerous front gardens being converted into parking areas, with RAC research from 2012 finding that a car will spend 80% of its time parked at the owner’s residence. This has had an unplanned impact which has increased the demand on surface water drains, as there is a much larger area catching the rainfall plus increasing rainfall intensities.
That’s according to Mark MacIntosh- Watson, engineering and technical
development manager at Brett Landscaping. “In Greater London alone, we know that land on private properties approximating an area of 3,124 hectares – the size of 22 Hyde Parks – has been converted from the original design of a front garden or pathway into driveways. This is a large area, especially when you consider a driveway for two vehicles, during a high- intensity storm, could have up to 450 litres of water running off it every fifteen minutes. But the rainfall has to go somewhere,” he says. McIntosh-Watson says that merchants need to be aware that water captured and managed off paved areas cannot be directed onto a public highway and, without planning permission, cannot be drained into the existing local drainage network.
“The grant of planning permission is
significantly weighted towards the outright specification of a sustainable system,” he adds. “A planning permission application requesting discharge into local networks can be made,
www.buildersmerchantsjournal.net January 2020
but will likely be flatly refused by planners, leaving the homeowner and builder with no choice but to use design and products that can dissipate water within the plot of land. “To solve these planning challenges and avoid a catch-22, merchants can suggest that paved areas can be installed using an entirely permeable pavement system, which captures all the rainfall at source, so there isn’t any rainfall runoff.
“Permeable pavements are straightforward to install. Typically, once the level of the subgrade is chosen, a geotextile is laid before a permeable sub-base (4-20mm Coarse Graded Aggregate) is set across the area. This is covered with a 50mm thick laying course (2-6.3mm Graded Aggregate) – before the permeable paving blocks are installed on top and jointed with the same 2-6.3mm
aggregate. This allows the water to soak into the ground. It may be the water is attenuated instead of simply soaking into the ground.” McIntosh-Watson says that occasionally features such as unusual ground conditions, steep gradients arise, but that there are rarely installation requirements that are beyond the available products on the market.
“There are several advantages for builders opting for permeable paving beyond the primary purpose of the management of
water.There is a greater range of products and finishes available across the market all designed with SuDS legislation and system longevity in mind. For example, Brett Landscaping’s residential permeable paving systems Omega Flow and Alpha Flow, which offer between 15 and 20 years of low maintenance service,” he says.
From a long-term performance objective, using paving ensures loose materials are not transferred from a driveway to the highway while providing a more pragmatic finish for mobility access to comply with the Equality Act – a major consideration for many family homes projects for an ageing population. Think about the effort required to push a wheelchair across an unbound surface, like gravel or chippings, or using walking aids on the same surfaces. Initially, the need for off-street parking and the surface water effects appear very conflicting, McIntosh-Watson says, but permeable paving does address several of the issues and creates benefits. “Builders can work with merchants to provide products and systems that lead to an end customer owning an attractive driveway that can make a small but significant difference in reducing the environmental impact of their car ownership.” BMJ
27
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
