Latest News from Interpave

INTERPAVE RESPONSE DEFENDS SUDS

Draft National Standards for Sustainable Drainage Systems (SuDS) were issued for consultation by the Department for Environment, Food and Rural Affairs (Defra) at the end of 2011. The Standards are intended to meet the requirements of the Flood and Water Management Act 2010 (FWM Act), which makes SuDS effectively mandatory. Interpave has just published its response to the Standards consultation, urging government to think again about a proposed ‘get-out clause’ and raising other important issues.

The draft SuDS Standards include an ‘Affordability’ clause where full compliance is only required up to the cost of equivalent conventional (piped) drainage. But, as Interpave points out, it is well-accepted that a universal – not sporadic - application of SuDS is essential to impact on the prevention of downstream flooding and pollution, particularly in the context of continuing ‘urban creep’ and climate change. Critical mass is essential for SuDS in the urban environment and there is no room for exceptions.

No other regulations or standards intended to protect lives, properties, businesses and communities (for example Building Regulations), or intended to address key sustainability issues allow for relaxation purely on the grounds of affordability. If adopted, this provision would set a dangerous precedent. The government seems to have forgotten about the major financial, as well as human, costs imposed on those affected by downstream flooding including householders, social housing providers, local authorities, infrastructure providers and insurers. In any case, when designed correctly and as an integral part of the project, SuDS are often lower in cost than conventional alternatives.

Defra proposes working in conjunction with other organisations over the next few months to develop more detailed guidance than the National Standards offer. Interpave has already indicated its willingness to be a part of this process and has in place a wealth of information on permeable paving and SuDS.

Interpave’s full response document can be downloaded here.

Defra launches SUDS Standards Consultation

The long-awaited draft National Standards for Sustainable Drainage Systems (SuDS) have just been issued for consultation by the Department for Environment, Food and Rural Affairs (Defra). At Interpave, we shall be pressing for the most sustainable solutions but we are concerned about a loophole enabling developers to avoid SuDS for cost reasons.

The draft National Standards have been developed to meet the requirements of the Flood and Water Management Act 2010, which makes SuDS effectively mandatory. They stress the importance of source control, water management near the surface, cost-effective operation throughout design life and integration of public space with SuDS. These are all areas where concrete block permeable paving makes an invaluable contribution, signalling the mainstream use of this important SuDS technique.

As part of the consultation process, Defra proposes working in conjunction with other organisations over the next few months to develop more detailed guidance than the National Standards offer. Interpave has already indicated its willingness to be a part of this process and there is a wealth of information on permeable paving and SuDS on this website. We shall also be discussing the draft Standards in more detail again shortly: watch this space.

However, we are particularly concerned about a proposed ‘get-out clause’ within the draft National Standards. In its current form, this will allow developers to avoid “full compliance with the Standards” where a SuDS scheme “is more expensive than an equivalent conventional design.” This move could significantly reduce our ability to defend against a repeat of the widespread flooding events seen in recent years where increased urbanisation and climate change have led to the sewer network being overwhelmed. Mandatory SuDS is seen by many as an essential component in the fight against repeats of these flooding events and their cost in both financial terms and human suffering.

The move could also be seen as unnecessary given the cost-effectiveness of SuDS schemes, particularly those incorporating concrete block permeable paving. Independent research commissioned by Interpave found that: “concrete block permeable pavements proved the most effective paving solution over 40 years” when using a whole life costing analysis. It also demonstrated that fully infiltrating permeable paving had the lowest initial costs wherever it could be used, when compared with various other impermeable paving materials using concrete block permeable paving with conventional drainage systems.

The draft National Standards consultation can be found at:
http://www.defra.gov.uk/consult/2011/12/20/sustainable-drainage-systems-1112/

PERMEABLE PAVING FOR AMENITY

There is more to concrete block permeable paving than just meeting the latest legislative demands to help reduce flooding. It can also provide a controlled source of clean water as a sustainable amenity for landscaping, ecology and water harvesting, as a leading SUDS specialist has demonstrated.

As a most versatile sustainable drainage system (SUDS) technique, concrete block permeable paving is particularly useful as a source control at the head of the SUDS management train. It reduces peak rate, total volume and frequency of rainwater runoff, and is also particularly effective at removing water-borne pollution. But it also offers the important – and often missed - opportunity of a gradual supply of treated water, something that Bob Bray of Robert Bray Associates exploits for amenity, harvesting and habitat enhancement in recent projects.

At a high-density town-centre housing scheme in Stamford, most public areas between buildings are concrete block permeable paving which also accepts runoff from other hard areas and roofs. Stored, treated water then passes from the paving directly into planted rills and canals, which add interest and much-needed greenery to the courtyard environment, before passing into the nearby river. This principle is expanded on a hillside Co-housing scheme in Stroud. Here, treated, stored water from concrete block permeable paved car parking feeds a ‘waterfall’ onto a planted swale, then via planted rills into a wildlife pond and existing stream.

At a pioneering school in Milton Keynes, a terraced sequence of permeable paving car parks removes pollutants, substantially improving the quality of water serving two ponds intended to encourage long-term population by wildlife - notably the ‘protected’ great crested newts indigenous to the site. Other sections of concrete block permeable paving at the school - on level areas used for play - collect and store rainwater for toilet flushing in the school buildings.

Bob Bray continues to explore the sustainable amenity potential for water treated and stored within concrete block permeable paving on various projects, including schools - many covered by an Interpave case study on Robert Bray Associates. For more information, visit the Interpave website www.paving.org.uk – the essential information resource on all aspects of precast concrete paving for the widest audience.

Interpave has published a case study document covering more of Bob Bray’s innovative SUDS projects.

MAKE SURE YOUR DRIVE IS LEGAL

Planning rules already in place in England - requiring permeable paving or on-site drainage for drives and garden paving - will shortly apply to Scotland as well. The rules encourage sustainable drainage to help reduce rainwater runoff and flooding.

Homeowners thinking about adding a new drive, patio or other paving in their front garden, or replacing tired old paving with something more attractive, will need to comply with extra planning rules. These have been in place for some time in England and local authorities are taking action with drives that don’t meet the rules.

Before the rule changes, paving anywhere in a garden with any materials was considered ‘permitted development’ – effectively, an automatic planning permission. This permitted development was stopped in England over 2 years ago for new or replacement paving bigger than 5m² in front gardens – such as drives. Similar rules should also start to apply to Scotland from the end of the year with The Town and Country Planning (General Permitted Development) (Scotland) Amendment Order 2011. They will apply to any area of paving in a garden between a home and the road.

The exception is ‘permeable paving’, such as concrete block paving specially designed for rainwater to soak through joints and the laying material. This looks similar to conventional block paving with a wide choice of attractive styles and colours. But it should have permeable material filling the joints and under the blocks, which looks like coarse, sharp stone gravel - not sand. As an alternative, paving that directs water to a soakaway, suitable area of garden or specially designed ‘rain garden’ where it can soak away is also permitted.

Any other paving that does not deal with rainwater on site needs a full planning application - with drawings, forms and fees - which will probably be refused anyway. If homeowners go ahead without either permitted development or planning permission, the local authority Planning Enforcement Officer could take action demanding an application or removal of the paving. Then, when it comes to selling a home, the buyer’s solicitor will want to make sure that necessary planning permissions are in place. If not, this could delay or even stop a house sale, and add to costs.

So, how do you know what paving really is permeable? Traditional tarmac and ‘printed concrete’ are obviously not and water will just run off. Also, conventional block or brick paving is not designed to be permeable. Its sand-filled joints soon clog up to provide a sealed-up surface and the material below is not intended to handle water. So, it will need to channel water onto a suitable garden area or soakaway, or onto an area of permeable paving to comply – not into a drainage pipe or onto the road.

Government guidelines provide some information and refer specifically to the Interpave website www.paving.org.uk for more help. Here you can download the free ‘Paving for Rain’ guide with essential information for homeowners on the rules and some other imminent legislation affecting all garden paving, and how to satisfy them.

On the Domestic website you can also find inspiration and guidance on the paving which is at the heart of creating and enjoying a beautiful and sustainable garden. It covers all the issues you need to consider when choosing and designing drives, patios and paths, as well as help finding the right manufacturers and installers, and practical help for DIY enthusiasts. Here, you can choose from a multitude of styles, shapes, colours, finishes and laying patterns to give just the right look for your garden.

SUDS IT'S THE LAW

Sustainable drainage systems (SUDS) will effectively become mandatory with The Flood and Water Management Act 2010, passed by parliament on 8th April. As the most versatile of SUDS techniques, concrete block permeable paving is set to become the norm for hard surfaces in all types of development.

Governmental planning policy guidance throughout the UK already requires use of SUDS such as permeable paving on all developments wherever possible and also encourages planners to take a central role in coordinating its acceptance by all. This requirement is supported by Building Regulations and other governmental guidance, including the Manual for Streets. In addition the Code for Sustainable Homes recognises the capabilities of SUDS to slow down and limit runoff, remove pollution and provide opportunities for rainwater harvesting both for external and some internal uses.

But The Flood and Water Management Act 2010, which received Royal Assent on 8 April, goes much further. It includes far-reaching requirements for SUDS on future construction work carried out in England and Wales. It applies to any construction work that creates a building or other structure, including “anything that covers land (such as a patio or other surface)”, that will affect the ability of land to absorb rainwater. In other words all new buildings, roads and other paving, whatever the size, type or scale of the project, will be affected – as well as alterations that have drainage implications. The Act may well apply to work that does not need planning permission, or indeed Building Regulations compliance, although applications for approval can be made with planning applications. Because the act is unconnected with planning law, current ‘permitted development’ rules do not provide exemption either.

When the Act has taken effect, applicable construction works cannot start until drainage systems have been approved by ‘Approving Bodies’ - generally county councils or unitary authorities – in line with national standards for SUDS. The existing right to connect surface water drainage systems to public sewers (under Section 106 of the 1991 Water Industry Act) will be restricted to those approved under the new regime, i.e. appropriate SUDS. Approving Bodies will be obliged to adopt all approved drainage systems except those on single properties and public highways. Road drainage will be adopted by Highways Authorities with design, construction and maintenance in line with the new national standards.

It is expected that the national standards, which must be met to gain approval, will be published by the government next year. They will cover the design, construction, maintenance and operation of SUDS. In the case of concrete block permeable paving, detailed guidance has already been developed by Interpave on all these issues - based on extensive international experience - which should form the basis of national standards.

In fact, a rapid growth is expected in the use of concrete block permeable paving, as it satisfies a range of needs that other SUDS techniques cannot. For example, it requires no additional land-take, unlike ‘soft’ landscaping features, making it efficient for high-density projects. It also satisfies the new Act’s specific definition of SUDS both to reduce flooding and to improve water quality, unlike attenuation tanks. And it provides a consistent, firm, safe surface to satisfy Accessibility regulations, unlike loose materials such as gravel. It is also worth remembering that concrete block permeable paving is not exactly new - either to the UK or internationally - but a well-established technology with projects performing well after 20 to 30 years use with minimal maintenance.

e:PAVE LATEST

Interpave has published another issue of its digital magazine e:Pave covering the latest developments in urban design, architecture, landscaping, sustainability and civil engineering – all with a paving focus. e:Pave takes over from Interpave's popular hardcopy magazine Pave-It.

Simply download this issue as a PDF file now and by registering you will be sure to receive future issues automatically via email. Back-issues of Pave-It can also be viewed here with a summary of articles covered in each issue.

SUSTAINABLE RESPONSE

The Draft Flood and Water Management Bill aims to make sustainable drainage systems (SUDS) mandatory on all new developments, with major potential for expanding the use of concrete block permeable paving. As part of the consultation process for the Draft Bill, Interpave has submitted a detailed response highlighting two particularly important considerations.

Firstly, as permeable paving us fundamentally unlike other SUDS techniques, National Standards related to the design, detailing, construction, maintenance and adoption of concrete block permeable paving should be developed in conjunction with Interpave and based on the existing Interpave Guide. Secondly, although most SUDS techniques fall outside the immediate highway area, permeable paving simply provides a sustainable alternative to conventional paving with its piped drainage, but on the same footprint. So, at adoption it will itself become the highway, along with impermeable areas draining onto it.

The limited maintenance requirements that apply to concrete block permeable paving, such as sweeping, are similar to those for conventional highways. It should, therefore, be treated similarly to conventional highways and associated drainage using Highways Act 1980, Section 38 adoption agreements with highway authorities. In any event, it is essential to remove any barriers to Section 38 adoption of concrete block permeable paving as a highway - as distinct from a drainage system as considered in the Draft Bill. To achieve this aim, it is recommended that the new National Standards also be applied to Highways Act Section 38 adoption.

Just as with conventionally paved areas, by applying correct details, design, specifications and guidance - all available from Interpave – developers, designers and adoption authorities can have confidence in the long-term performance and life span of concrete block permeable paving as an essential, mainstream technology.

NEW FRONT GARDEN RULES

Originally part of the government’s water strategy launched in February, new planning rules will apply in England from 1st October. They aim to encourage homeowners to use permeable paving, rain gardens and similar sustainable methods when installing new or replacing existing paving in front gardens.

Homeowners will no longer be allowed to pave their front gardens without planning permission - unless permeable surfaces such as concrete block permeable paving are used or water is otherwise able to soak into the ground, for example using rain gardens. Otherwise, planning permission will be required for hard surfaces over 5m², involving drawings, application forms, a fee of £150 and around 8 weeks for a decision. And, of course, permission may well not be granted anyway.

These measures form part of the fight against flooding and move towards sustainable drainage systems. Interpave has already recognised the need to address this issue. Straightforward guidance is available to homeowners, garden designers, contractors and others involved in domestic paving, on sustainable drainage to avoid water discharge into sewers when using concrete block and flag paving for an attractive, safe and firm surface. It is important to remember that loose materials such as gravel do not meet Building Regulations requirements for safe access of disabled people to homes.

Concrete block permeable paving can be used to allow rainwater to filter through gaps between the blocks, and eventually into the ground or to drains. The same principle applies to conventional concrete block and flag paving installed to channel water into a ‘rain garden’ where the water has time to soak into the ground. Both methods are covered in the Interpave guidance which aims to provide a straightforward, step-by-step design procedure - based on design calculations using sound engineering principles – together with advice on construction and plants.

Click Here for further information >>

The government guidance stresses the importance of using experienced contractors and refers to trade associations including Interlay to find suitable companies. Further information >>

GREEN PAVING

The recently launched BRE ‘Green Guide to Specification’ provides independent endorsement of the low environmental impact of precast concrete paving, particularly in comparison with imported materials.

The Green Guide rates a wide range of elements from ‘A+’ for best environmental performance to ‘E’ for the worst. Three different paving scenarios are considered covering: Pedestrian Areas, including communal spaces, walkways and garden paving; Lightly Trafficked Areas, such as car parking; Heavily Trafficked Areas, for heavier vehicles or repetitive car traffic.

The summary environmental ratings for a range of precast concrete paving specifications – covering blocks, flags and ‘grass concrete’ units - are generally ‘A’ or ‘A+’ across all three scenarios. These ratings reflect the on-going environmental investments and improvements made by Interpave manufacturer members, as well as by the cement industry generally. Local material sourcing and product supply is also important, and equivalent paving products shipped into the country bear a substantial CO2 emission load. Some imported stone paving products are also included in the Green Guide – generally with much poorer environmental ratings than their precast concrete equivalents and half with the worst ‘E’ rating.

  Download Interpave's new Environmental Impact of
  Paving document >>

CUTTING
In response to concerns about the impact of dust generation resulting from cutting building materials on site, Interpave has produced guidance for precast concrete paving products following discussion with the Health and Safety Executive. Click here >>

PAVING TRAINING
A programme of training courses covering all aspects of paving and hard landscaping is being run by The Hard Landscaping Training Group, an initiative funded by CITB and supported by industry. The paving programme, which runs to the end of November, includes individual courses covering setting-out and installation of paving blocks, flags, kerbs and channels. Of particular importance is the permeable paving course, with this essential sustainable drainage technique rapidly growing in popularity. For information on this latest programme of courses, the HLTG and other training visit: www.hardlandscapetraininggroup.co.uk