Paul Barham is an architect and associate of John Gilbert Architects when he's not tending his allotment, working with the Camcorder Guerillas, or riding a horse in Spain.

28/110/2009 An in-depth exploration of Ecohomes as an assessment tool for new housing and it’s relevance to Scotland.

Why Ecohomes?

Rationale

As architects we need credible assessment tools to help us meet the challenges of designing sustainability into our projects. Clients and funders need standards to establish benchmarks and designers need to be able to assess and compare the environmental impact of design decisions across a wide range of sustainability indicators.

BREEAM Ecohomes provides one such tool, encompassing energy use, CO2 emissions, transport, pollution, flood prevention, the procurement of materials, water use, site ecology, the health of the occupants and the management of both construction site and the building itself.

Ecohomes and BREEAM

The Ecohomes assessment scheme for houses and flats was the first of the ever-expanding BREEAM family of assessment and certification schemes for the environmental performance of buildings. Ecohomes was conceived as a voluntary scheme which would achieve popularity by establishing a series of benchmarks for overall environmental performance across a wide range of indicators.

The scoring process is complex but leads to a simple and straightforward environmental credit awarding the successful scheme either a ‘Pass’, ‘Good’, ‘Very Good’ or ‘Excellent’. Successive revisions to construction regulations and improvements to environmental legislation mean that in 2009 it is unlikely that any housing project would achieve less than a ‘Good’ rating.

BREEAM market Ecohomes as an independent and credible scheme, based on an holistic and customer-focused approach. As an Ecohomes assessor I have an obligation to issue completed assessments to BREEAM for Ecohomes certification and for BREEAM to audit a representative cross section of the work submitted to them.

Other voluntary certification schemes exist alongside Ecohomes in comparison to which the BREEAM scheme might be seen as less “deep-green” or more developer-friendly. However Ecohomes covers wider range of assessment criteria than the other schemes, is more immediately accessible and as part of the BREEAM family is aimed at a broader cross-section of the built environment.

The Scottish Context

In England and Wales, Ecohomes has now been superseded by the Code for Sustainable Homes (CSH), which has become a mandatory standard for housing south of the border. In Scotland, Ecohomes remains as a voluntary standard, although one which is increasingly being made a condition of funding.

While Scotland is tied into UK strategy on matters of energy, the environment remains within the remit of Holyrood, and the Sullivan Report outlines the strategic context for reducing Scotland’s CO2 emissions from the built environment in a series of steps leading up to zero carbon by 2030.

Scottish planning policy in the shape of SPP6 requires all large developments to incorporate on-site zero and low carbon equipment contributing to reduce CO2 emissions at least 15% below those required by the 2007 building regulations. The 2010 building regulations will demand further reductions in emissions and energy use.

Different local authorities have implemented different methodologies for implementing these targets, including Ecohomes. In Glasgow, all publicly funded housing now needs to achieve an Ecohomes rating of “Very Good”.

Ecohomes in Practice

John Gilbert Architects has completed projects where achieving Ecohomes Very Good has been a voluntary commitment on the part of the client. This experience is useful in my work as an assessor where the need to meet this standard is now being stipulated through the planning and funding parameters laid down by central and local government agencies.

And as a practising architect, my work as an assessor continues to give me an insight into how assessment schemes such as Ecohomes can be used as a helpful aid to sustainable design.

Relevance to Scotland

There has been a reluctance in Scotland to follow the route of England and Wales in adopting the Code for Sustainable Homes. This would still appear to be the case with the Scottish government looking to achieve improved energy and emissions standards through an increasingly strict regulatory framework.

What will be the future of Ecohomes in this system?

Ecohomes has to some extent become the poor relation of the Code, with few recent reviews or revisions in comparison with CSH. At times I have had a strong sense that BREEAM in Watford does not see it as having a long term future.

However, Scotland has different needs from England and Wales, a different topography, climate and building typology. These give rise to different priorities relating to travel distances, the procurement of materials, emissions and the sustainability of isolated communities. And is water use such an issue in a wet climate?

The inclusivity and adaptability of Ecohomes should continue to provide us with a robust system for the evaluation of housing in Scotland, embracing both building performance and the wider issues of site ecology, and developing in response to client feedback, technological developments and to changing strategic priorities. As such the Ecohomes model could be used to establish a recognised over-arching design and procurement standard referenced to both Scottish building regulations and Scottish planning policy.

How it Works

The Assessment Process:

BREEAM recommend that assessment appointments include an element of pre-assessment advice. Although this is not an essential requirement, if good advice and useful feedback can be provided at an early stage it is likely to help the project achieve its target.

As an assessor my main tool is the Ecohomes Guidance, which sets out reasonably clearly how the scores should be calculated. Some of the credits are more readily understood than others – both in terms of how they are calculated and why they are there in the first place.

I find the pre-assessment consultation particularly useful in this respect, since it give me the chance to explain the more byzantine calculation methods used in determining some of the credits. The pre-assessment stage also helps to make sure that the designer/ developer is able to achieve those credits which are more easily achievable and establishing a benchmark rating for the project at an early stage. This should help the design team make the value judgements necessary to introduce any changes that may be required to bring the design up to the target standard (most often “Very Good”).

It is important then to know the options which will be available for getting additional credits and what the implications will be for the client and building user, in terms of cost, maintenance and general usability etc.

To carry out the assessment I need to see the drawings and specification for the project – I find it easiest to ask for the full tender issue as many of the Ecohomes criteria cannot be confirmed until this level of information is available. There will also be additional information, such as mapping details showing access to local amenities and public transport, information on site ecology and management issues. I always ask for the Ecohomes Developer Sheets to be completed – these 200-odd pages may seem daunting but they are an assessment requirement: I generally suggest that the developer treat them as a checklist; all I really need to know is whether each particular credit is being sought and to use the Developer Sheets to identify where the information in support of that credit is provided.

Post-Construction Review

The Post-Construction Review (PCR) is an integral part of the Ecohomes methodology but stands alone as a separate entity from the Ecohomes assessment. This may be for practical reasons, since design and completion may be separated by an interval of several years, however, without some sort of check at completion the design stage Ecohomes rating could be rendered meaningless, or worse, misleading.

Without PCR a loophole exists which is obvious to anyone who has been involved in a savings or value engineering exercise to allow a project to progress onto site within budget – especially where Ecohomes credits have been achieved through add-on rather than integral elements to the design.

As an assessor I have found that until recently there has been little interest expressed by clients in PCR. Also, its methodology is less clearly defined than that of the design stage assessment, making it more difficult to price as an assessor. However, we have been advised that where Ecohomes standards have been defined as a funding parameter there is now more emphasis being put on the PCR by funders – as should be the case.

Assessment Criteria and Weightings

Ecohomes assessment criteria are loosely assembled under eight headings, each of which is ascribed a percentage weighting in the scoring process:

• Energy - 22%
• Transport - 8%
• Pollution - 10%
• Materials - 14%
• Water - 10%
• Ecology - 12%
• Health - 14%
• Management - 10%

BREEAM state that these headings and weightings are subject to periodic re-assessment by a review panel drawn from a wide range of organisations encompassing policy makers, academics, industry representatives and environmentalists.

Assessment Criteria

There are 33 different assessment criteria each with its own scoring method. These are given weightings according to the percentages given above. The Ecohomes Pre-Assessment Estimator, available as a free download from the BREEAM website, provides a useful checklist for the assessment process, including weighted percentages against each credit.

The following paragraphs give a brief overview of each of the assessment criteria and the percentage points available, along with some key issues to address if maximum credits are to be achieved.

Energy

Ene 1 (13.75%) depends on the average Dwelling Emission Rate (DER) for all dwellings taken directly from the SAP2005 calculation worksheets.

Ene 2 (1.83%) is a measure of the building envelope performance and depends on the average Heat Loss Parameter (HLP) for all dwellings, also taken directly from the SAP2005 worksheets.

Ene 3 (0.92%) is awarded for providing a secure drying space, which can be inside or out but requires the installation of fixed equipment.

Ene 4 (1.83%) is awarded for the provision of eco-labelled white goods; or half of the total credits available for providing information and advice on eco-labelling.

Ene 5 (1.83%) is awarded for the provision of dedicated low energy lights within the dwelling, full credits for 75% of all fittings, half credits for 40%. Fluorescent fittings will meet the requirement but issues of personal choice and affordability should also be considered.

Ene 6 (1.83%) is awarded for the provision of dedicated low energy lights externally and covers both space lighting and light sensor and PIR operated security lighting. The security credit can be awarded by default if compliant space lighting only is provided.

Transport

Tra 1 (2.00%) depends on proximity to public transport and is more onerous for urban than rural areas. Information should be provided on local bus and/ or train services and safe pedestrian routes to these services shown on a scale plan.

Tra 2 (2.00%) is awarded for providing cycle storage. This would seem easy but the terms of this credit are onerous: storage is to be outside the dwelling, secure, enclosed on 3 sides and roofed. Provision for 95% of dwellings achieves full credits; half credits for 50% provision.

Tra 3 (3.00%) depends on proximity to local amenities and again is more onerous for urban than rural areas. Information should be provided on distance on foot to a range of amenities and safe pedestrian routes to these services shown on a scale plan. The same plan can be used to show information for both Tra 1 and Tra 3.

Tra 4 (1.00%) can be awarded for the provision of a home office giving the opportunity to work from home. Where dwellings have been designed to Housing For Varying Needs (HFVN) standards there is likely to be space to achieve this – however this must apply to all dwellings which may be problematic for small flats.

Pollution

Pol 1 (0.91%) is dependent on the avoidance of insulating materials with a high ozone depleting potential (ODP) or high global warming potential (GWP). This relates to foamed and extruded plastics. Relevant information should be obtained from manufacturers and referenced to both details and specification.

Pol 2 (2.73%) can be awarded in full where average NOx emissions are no higher than 40 mg/kWh for 95% of the dwellings. Class 5 boilers will achieve two-thirds of the credit; Class 4 boilers one third. NOx data are not included on the SEDBUK database and manufacturers’ literature is not always clear in this respect.

Pol 3 (1.82%) is awarded for reduction of surface run-off from roofs and hard surfaces by sustainable drainage techniques, depending on the susceptibility to flooding of the site. Drainage drawings, DIA and confirmation of percentage attenuation will be required from the Structural Engineer. Often the requirements of the water authority may already exceed those required for full credits.

Pol 4 (2.73%) can be awarded where proposals include the provision of renewable and/ or low emission energy sources. It is important that the chosen technology is appropriate to the site – i.e. not “eco-bling”! – and therefore the credit can only be awarded where a feasibility study has been carried out and its results implemented. Maximum credits are achieved for a 15% reduction in projected energy demand; two-thirds for a 10% reduction.

Pol 5 (1.82%) is awarded where the site is in an area of low flood risk. Half credits can be awarded for keeping ground floors and parking above the flood risk level in areas of medium flood risk. In Scotland, the on-line SEPA flood maps are a useful source of information but flood risk should be confirmed by the Structural Engineer.

Materials

Mat 1 (7.23%) represents an assessment of the environmental impact of materials. Building and site are divided into seven basic elements and each construction type compared to the elemental constructions listed in the BRE Green Guide – the on-line version which contains some significant changes can now also be used. Green Guide ratings are given in a range from A+ to E; to achieve Ecohomes credits will require a majority of A or A+ ratings for each basic element.

Mat 2 (2.71%) examines the responsible sourcing of primary building elements under 8 headings. Only the four most frequently occurring materials are taken into consideration, or those making up 80% of volume of each element. Materials constituting less than 10% of each element are ignored. Sourcing is assessed on the basis of certification and environmental managements schemes (EMS) and the availability and probity of chain-of-custody (CoC) information. This has always been problematic but now, at least in the case of timber, FSC and PEFC schemes are sufficiently well known and adopted by the construction industry for some of the available credits to be obtainable.

Mat 3 (1.35%) examines the responsible sourcing of building finishes under 8 headings. The methodology is identical to that used for Mat 2 and the same issues apply. Since many finishing elements are made of timber, these credits ought to be obtainable, however there are also many composite finishing materials whose origin will be difficult to ascertain.

Mat 4 (2.71%) awards credits for recycling provision within the finished development. Full credits can be awarded if both dedicated internal storage and either external storage or a local authority collection scheme are in place.

Water Use

Wat 1 (8.33%) assesses the water use of the household on the basis of the appliances installed. A higher score will be obtained where dual flush toilets are installed, low volume showers over baths, and flow restrictors on taps.

Wat 2 (1.67%) is awarded for the provision of rainwater collection for watering gardens and landscaped areas. This does not form part of the drainage attenuation but water butts may be worth considering for the credits to be gained here.

Ecology

Eco 1 (1.33%) is awarded for building on land which is of intrinsically low value. Almost any brownfield site will achieve this credit.

Eco 2 (1.33%) depends on the appointment of a suitably qualified ecologist and the adoption of their recommendations for the site.

Eco 3 (1.33%) is awarded for the protection of any existing ecological site features. This should be shown on the site landscaping layout. The credit is awarded by default for brownfield sites or where a credit has been awarded under Eco 1.

Eco 4 (5.33%) measures the change of ecological value of the site in terms of the net increase or decrease of species of wild flora and fauna assessed to be present. Where an ecologist is appointed this should form part of their report; otherwise existing and proposed land use are compared across the site. A credit may still be awarded where there is no net increase or even a small reduction in species.

Eco 5 (2.67%) is awarded for maintaining a small building footprint: full credits if the average floor area to footprint ratio across the development is greater than 3.5; half credits if the ratio is greater than 2.5 for houses and greater than 3.5 for flats – i.e. at least 50% of flats need to be 4-storey and 50% of houses 3-storey.

Health and Well-being

Hea 1 (5.25%) is an assessment of adequate daylighting. Credits are awarded for the lighting of kitchens and living rooms and for there being a view of the sky in all rooms. The assessment involves looking at the geometry of all rooms in the development – internal kitchens and small kitchen windows will lose credits.

Hea 2 (7.00%) awards credits for sound insulation between dwellings, with additional credits for exceeding insulation standards by 3dB and 5dB. Achieving any credits is likely to involve more sound tests than compliance with Scottish regulations. The testing also has to be carried out to the standards laid down in the English and Welsh building regulations.

Hea 3 (1.75%) is awarded for the provision of a private or semi-private outdoor space. This will be met by a private or communal garden; balconies and roof terraces also acceptable.

Management

Man 1 (3.00%) is awarded for the provision of a home user guide, with maximum credits for covering information relating to both the environmental performance of the dwelling and the site and its surroundings. The tenant’s handbook is the obvious place to put this information for public sector housing projects.

Man 2 (2.00%) depends on the contractor demonstrating a commitment to comply with or, for the full credits to go significantly beyond, best practice site management principles. The most common scheme is Considerate Constructors, which can be made a prequalification requirement in the procurement process.

Man 3 (3.00%) requires the contractor to monitor and manage construction site impacts. Full credits require the implementation of 4 out of 6 best practice site management policies covering CO2 emissions, water consumption, dust, water pollution and timber sourcing and reclamation on site.

Man 4 (2.00%) is awarded for meeting Secured by Design security standards. Full credits will be achieved for a commitment to working with the police architectural liaison officer through to achieving a Secured by Design award and if doors and windows themselves meet the Secured by Design requirements.

Assessment Feedback

Common Assessment Issues

When the assessor is appointed too late in the design process there is relatively little opportunity to for the client and design team respond to the assessor’s advice. Issues such as orientation and house layout will have a bearing on building envelope performance, daylighting and adaptability. However it may be too late to change the design. If the assessor is able to provide advice at an early stage it will also be useful in terms of establishing the cost parameters for the specification.

Repeat clients such as housing associations and developers may be more or less familiar with the Ecohomes assessment process. In these instances there may be a case for appointing the assessor in a more limited advisory role, although I would argue against omitting this part of the appointment altogether – since I always find myself needing to give advice anyway.

Another issue is the late issue of information, so that the assessment cannot be completed until after the building has started on site. This clearly involves a risk to the client where achieving a specific Ecohomes standard has been made a funding requirement.

I have been asked whether a Post-Construction Review (PCR) can be carried out instead of a design stage assessment in cases where works have already started. BREEAM is clear on this point: a design stage Ecohomes assessment must be carried out before any Post-Construction Review (PCR) is undertaken – not least since the design stage assessment forms the basis for the PCR.

Monitoring and Post-Occupancy Evaluation (POE)

In some instances I have been advised that the funding body requires an assessment to be carried out but with no requirement to meet any particular standard. In these cases the only benefit I can see is that it helps provide a benchmark for our housing stock but I can only see it a missed opportunity for achieving higher standards.

The separate and stand-alone Ecohomes XB system has been developed as a benchmarking tool for existing housing stock. It has been devised for use by housing management organisations and the intention is that it should not require the appointment of a specialist Ecohomes assessor – although I am at present providing assistance to one housing association in setting up such a system.

I welcome the increased emphasis on the Post-Construction Review and believe that a PCR should be carried out at all projects where an Ecohomes certificate has been issued. I can see that various parties to the development may have their reasons to be less than enthusiastic about a PCR being carried out, however, it will be in the long-term interest of all concerned to obtain feedback, to see where the finished development has met or exceeded expectations and where it has fallen short.

I would also advocate that PCR should form part of a more over-arching Post-Occupancy Evaluation (POE) of the dwelling. POE should be aimed at providing useful feedback and lessons for the future, involving year-round monitoring, and should be built into contractual relationships to encourage problem solving rather than the apportionment of blame as their goal.