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 Quite often the answer is fairly simple: Permeable Paving Why should I consider using it? With the increased risk of flooding and the expansion of green field developments, more builders are choosing permeable paving as a way of reducing that risk and complying with building authorities. In urban areas too drainage systems can be overloaded if poorly designed and installed paving is used. As well as the environmental damage there’s the financial harm to homes and businesses to consider – the floods in June of this year were reckoned to have caused over £1.5 billion of damage! And if you haven’t yet heard of SUDS yet you soon will. Sustainable Urban drainage Systems are designed to reduce the effect of urbanisation on the environment and are now increasingly specified by Local Authorities. The Department of Trade and Industry ‘SUDS Best Practice Manual’, published by CIRIA 2001 (CIRIA C523) defines that a sustainable urban drainage system should consider certain basic requirements including: “...runoff from a developed area should be no greater than the runoff prior to development.” So what is Permeable Paving? Permeable paving allows rainwater to infiltrate to the layers beneath the surface, in the same way a grassed area would. The rain water can then be slowly discharged to the water courses, minimising its impact and preventing flooding. As well as this permeable paving can help to remove pollutants from water. There are two proven methods now in widespread use across the UK. The first is a grass protection and gravel retention system such as DuoBlock, and the second is a geotextile based system using specially designed paviors. How do they work? Grass protection and gravel retention As an interlocking grid that allows grass to grow through or to be filled with gravel, DuoBlock is capable of supporting heavy traffic at the same time as retaining an attractive, efficiently draining parking or thoroughfare. With an integral locking mechanism DuoBlocks fit easily together providing a rigid, hard-wearing structure. Laid over free-draining soil large areas can be laid quickly without the need for any special tools or equipment. Each cell is open to the next for efficient lateral drainage, which helps avoid pooling during heavy rain. As well as this it encourages root growth allowing grass to easily grow and provide an attractive surface. The cells can also be filled with gravel to suit any existing landscaping scheme. Geotextile based system In this method a free draining block pavior is laid over a normal sub base under which a specially designed geotextile is laid. The geotextile provides the ideal habitat for microbes that consume oil and other pollutants. This means that any water run-off is cleaner and puts less strain on water treatment plants further downstream. Underneath the geotextile a gravel sub base is used to create an aquifer and can also incorporate a geogrid for extra strength in heavy traffic areas. As well as this the design can include a membrane to create an underground tank which can store and release water in a controlled manner.   How will it help me? DuoBlock avoids the need for expensive drainage systems and reduces the cost of installation. As well as this the design allows for a wide range of natural looking finishes including grass and gravel at the same time as providing a hard-wearing surface. Geotextile systems give the same free-draining properties where a hard surface is required. These also give you a wider range of options for creating tanks and drainage systems in line with any specified SUDS. What are the environmental benefits? Builders are increasingly challenged by their customers and authorities on how ‘green’ their methods are. By using permeable paving you’ll be able to reassure them with the following facts: Puts cleaner water put into the sewerage system Helps replenish the existing water table Reduces the risk of flooding and standing water following heavy rainfall Causes less pollution to rivers and streams following storm water run-off from urban areas For more information on permeable paving and how it can help you, contact our sales team on 01455 617 139 or email sales@geosyn.co.uk.                                

Geotextiles used to be seen as the preserve of the “big boys”, but now builders of all sizes are using them to save time, money and give a more professional, longer-lasting job. So what exactly is a geotextile? Geotextiles are permeable fabrics made from polypropylene or polyester. Used under the surface they can increase the load-bearing and lifespan of roads, driveways, embankments and drainage ditches. Resistant to soil acids and alkalis and impervious to fungi or rot, they come in two types: Woven and non-woven. How will a geotextile help me to do a better job? Geotextiles have three key functions: Separation, Reinforcement and Filtration… Separation Without a geotextile, aggregate and subsoil can mix causing excessive settlement which in return causes rutting. Using a geotextile over the subsoil before laying the aggregate will prevent downward movement as well as the upward pumping of weak subsoil into clean stone. Reinforcement By spreading the load horizontally across a wide area geotextiles can increase compaction of the aggregate base; improving the strength and extending the life of all types of paved and unpaved traffic areas. Filtration Geotextiles retain fine particles in the soil while allowing the free movement of water. In this way they can restrict soil from migrating into perforated drainage pipes and prevent them from silting up. Used in stone-filled drainage ditches they provide a continuous and consistent filter and produce a higher quality construction – Even better it reduces the depth needed so you won’t have to dig as deep! How can a geotextile save me money? First of all you’ll spend less on materials – The right grade of geotextile will maintain the same load support with less aggregate. This also means you’ll spend less time excavating. And because they give a more durable result it’s less likely that you’ll need to return to repair minor defects. All of this means that a geotextile, far from being an extra cost, will easily pay for itself and more. There’s no need for training or special tools either and it’s so easy to install your mum could do it! I thought they were just for weed control? Weed control just happens to be one of the added extras that geotextiles give on top of all the other benefits. Why is a geotextile better than a weed fabric? Most weed suppression fabrics are very weak and light. Geotextiles are at least 3 times stronger and more durable too. Try using them on bare soil and covered with mulch or gravel for long-term weed control and moisture conservation. What’s the difference between a woven and non-woven geotextile? Woven geotextiles are manufactured by weaving together narrow strips of film while non-woven geotextiles are created by entangling plastic fibres or bonding them chemically or with heat. Wovens increase the load capacity of traffic areas by distributing weight more evenly. Non-wovens also do this but combine excellent drainage and filtration to prevent the pooling of surface water. Both have outstanding separation properties to prevent sub-base contamination which can result in an uneven surface and construction failure. For more information on which is the best for your next job contact our sales team on 0870 850 1018 and look forward to bigger savings and a more professional, longer-lasting result.

Geosynthetics Ltd, has recently secured two significant orders with Ecotricity and The Wind Prospect Group to supply Tenax Bi-orientated Geogrids for use in the construction of site access roads to the new developments. The first order for Stags Holt Wind Farm in Cambridgeshire was to supply Wind Prospect Ltd with 48,000m² TENAX LBO Geogrid. The site will include 9 wind turbines each standing 59 meters high and is due for completion in September 2007. The second contract is to supply Ecotricity with 28,000 m² of Tenax LBO Geogrid for the new wind-farm development at Fen Farm in Lincolnshire. Construction is due to begin in May and will feature twenty new turbines, each standing 65-meters high that will generate an extra 43.5 million units (kWh) of green electricity every year. Geosynthetics Ltd produced the designs for the site access roads on both schemes. Following receipt of a soil investigation report, a design calculation was produced to ensure the most cost effective construction was utilised for each scheme. The advantages of this type of approach include: · Ensuring the road will withstand the duration of the site (25 years). The design was specified to 1,000,000 standard vehicle passes. · Minimising the amount of fill material required (up to 40%) therefore reducing costs. · Minimising environmental impact – by using less aggregate that needs to be imported onto the site reduces vehicle movement and reduces the use of quarried material. · Ensuring the site access road would be strong enough to withstand loadings of the wind turbines and heavy vehicle usage during the construction period. Using TENAX LBO geogrids provides a solution that maximises the sustainability of the site whilst reducing costs and minimising environmental impact. Both schemes were supplied through one of Geosynthetics Ltd nationwide merchant distributors.