The first site of two visited on the day, was The Curly House, designed by Ecotecture Architects with consultancy from Kithurst & constructed by Kithurst Builders. The design team also included BLB engineers, all three consultants are members of the AECB. The client recognised the wealth of knowledge and experience that the AECB embodies and this would have influenced the decision to appoint said consultants.

Planning stage

The home is located on the south downs way, in an area of outstanding natural beauty, so achieving a permission for a high concept contemporary home was a tall order. Much discussion revolved around how this was achieved and what pitfalls may come up for those embarking on similar projects. Ecotecture worked along side the planning consultants DMH Stallard in interpreting the latest (at the time of 2008) planning legislation. After an initial refusal on the site for a 2 storey development timber frame Passivhaus, the design team went back to the drawing board, and focused intently on the wording of the latest planning documents. It was acknowledged that a semi subterranean building would be required to meet the accommodation requirements of the client, whilst setting the proposal down into the countryside to become more attractive to the local planning department. The quote which the tipped the balance in the projects favor was in PPS 7; “Modern designs reflecting traditional detailing or using traditional materials, or traditional designs using modern materials, can allow building design in the AONBs to continue to evolve without losing local distinctiveness and being uncomfortable in their context.” This policy statement was key in delivering the contemporary architectural style, which was such an important feature for the client.

Technical development.

The challenges of producing a very low energy building which is organic in form and affordable within a highly exposed site location, started when the detailed drawing packages where produced. The project went through many iterations before a fixed construction method was identified. Antoine from Kithurst Builders described types of construction considered including; straw bale, timber-frame, timber / steel frame hybrid, I-Joists & Metal framing / lattice joists. Each of these construction methods have there benefits and inherent weaknesses. The leading factors in the decision making process where; robustness, energy efficiency and cost. For these reasons Nudura ICF (insulated concrete formwork) and OP-Deck (thermally broken super insulated deck system) where chosen to be specified within the detailed drawing package.

In terms of the structural design, the structural engineers (BLB engineers) had to be inventive with how the reinforcement was specified within the property. Building codes in the UK are recognised to be far more stringent than that of Canada, where the majority of ICF (insulated concrete formwork) systems are in common use. The UK codes call for reinforcement levels which would considerably increase cost on the project and the level of embodied energy within the building fabric. Using approved inspectors in preference to local building control, gave the design team more flexibility to reduce the need for structural reinforcement.

The two building systems produce a practically zero thermal bridge construction, and enable the overhanging brise soleil to be installed without the detrimental cold bridge that is typically associated. There where however, a few areas where the contemporary design proved challenging to achieve the air tightness standards, whilst maintaining a thermal bridge free thermal envelope. The best example of this is how the tips of the crescent are formed in the glazed structure (see detailed drawing below).

Detailed drawing showing construction of horn

Thermal performance & embodied energy.

Initial air tests show the property achieving 0.3 air changes per hour, Antoine from Kithurst builders has intentionally surpassed the air tightness standard required for Passivhaus compliance. The front door to the property is not passivhaus compliant and is in fact an eccentric pivot door, which has inherent air tightness issues. By surpassing the Passivhaus standard Kithurst builders have made allowance for this poorer performing building element. This seems a minor detail, but this is something which should be considered when a client has a good eye for detail, and would be unhappy if the home of their dreams did not contain such an important feature.

Jake White from Ecotecture described how the concrete core within the Nudura ICF plays an important role in the balance of temperatures in the building. “When we first saw the system, we were not convinced that the product utilised its thermal mass in the most effective way. We were heavily reliant on Kithurst’s experience with the product and we are glad this is where we placed our trust. We now understand that having the core locked away from the internal environment has a positive effect on the temperature in the building. The issue with exposed thermal mass is it can quite easily cause a feedback loop, each night emitting slightly less than the amount absorbed during the daytime. Using thermal mass which is isolated in this way increases the lag between absorption and re-emission. This is great for ironing out spikes of unusually hot October weather!”

The contentious matter of embodied energy was raised a few times during the visit. This build will not sit comfortably with all involved in green building, it would seam counter-intuitive to utilise such high embodied energy products as expanded polystyrene and concrete in the delivery of an eco home. Arguments against the use of these products are obvious, discussions supporting the choices made include site appropriateness. The location of the dwelling is infamous for extreme exposure to the elements, its position on the South-downs Way can mean blisteringly cold winters and very hot summers. The choice to use a heavier construction relates to the level of site exposure. The semi subterranean nature of the design also means the use of materials which suffer from damp problems could not be considered as a viable alternative. Jake White from Ecotecture says on the subject “We consider that the investment in terms of embodied energy stacks up in this particular scenario, this home will be passed from generation to generation, with practically no running cost. This investment does makes sense to us. We cannot see what the future will hold, but I am happy that this family and it’s future generations will be unaffected by escalating fuel costs and in a healthy and comfortable environment.”

AECB South East are looking for new projects to visit, please contact (Mel Laurie) on (01444 416745) for suggestions of projects in and around the Brighton area, which would be keen for a future visit.

Green Home Exchange

When you swap homes with someone in a London Eco Home Exchange program such as the ‘The Green Theme Home Exchange’ or Gum Tree House Exchange Program, you’re not only planning a holiday, but helping to support something important: a more sustainable tourism. Haven’t you ever wanted to explore the world, but found it too expensive? If you own your own home, you can go anywhere and spend practically nothing on lodging! There are many people in many countries waiting to trade their homes with you for different lengths of time. You could trade with someone in a variety of countries like Spain, Australia, America, New Zealand, or even a different part of England.

A holiday can be stressful and exhausting. You have to pay enormous hotel fees for accommodations that don’t even make you feel at home. Along with eating out every night, a holiday can become really expensive. Well, not anymore! When you swap homes with someone, you’ll have all the luxuries of home. You can choose to be in the city, or off in some exotic new countryside. It’s up to you. It makes all the difference to have a place to heat some water for a cup of tea or to be able to stay in for a night, instead of being forced to sight-see constantly.

Naturally you should be cautious about who you open your home to. It’s ideal to meet the people that you will swap with, to get a sense of what kind of folk they are and how compatible you will be with them. In any case, since you trust them with your home, they trust you with theirs. If you want more assurance than that, there are reviews to read online, including ratings of their houses and past holiday experiences. The program makes you even more comfortable with a well written contract, for most house swap programs, where homeowners are fully protected from any unforeseen event. These safety measures make eco house exchange programs practically risk-free, and the best option for your holiday vacation or retreat.

I have just got back from a site visit in Manning’s Heath, West Sussex. The client has asked us to come and over see the works we have helped design, on an ad-hoc basis. We are happy to be involved with progress on site, particularly as our client has fully embraced the “fabric first” approach.

The Orchard is the retrofit and conversion of an existing commercial building to a new dwelling. The “fabric first” approach was identified at an early stage as a key to “being the last building in the area, to loose the winter snows from its roof”.  The project features U-values below 0.15W/m2K and all round good air tightness.

We are using an american insulation product which is a spring off from the ICF movement. The product has good thermal continuity and is extremely quick to install. The contractor is keen on this product, as there team are well known for turning projects around quickly. In the 2 weeks since the contractors have arrived on site, the existing floor screed and basic insulation levels have been lifted and the low performance windows have been removed.

Ecotecture will have a basic involvement with the project as it goes forward on site, we will be around to trouble shoot details, or help with decisions on alternative materials. We will be paying particular focus on the air-tightness of the building. We feel confident that this retro-fit could well be exemplar in its energy performance.

The building is very strong in its form, particularly as the ICF system is a very bright blue colour. The building will be finished in a self coloured render which will work well with the curves to produce a soft finish, this in conjunction with the curved lines of the deck, the additional landscaping and the brise soleil will sit the building down into the landscape and produce a building of exceptional architectural merit.

The core idea behind the building design is the pushing the envelope whilst maintaining balance between energy efficiency and high design concept. The building has been thermally modelled within IES, and shows that the curved design does not compromise the performance, in-fact it this specific design it actually enhances it.

The relationship between air-tightness in buildings and mechanical ventilation and heat recovery is an important one. This is a topic continuously & ferociously debated by members of the well respected green building forum the AECB. It is widely agreed that a minimum air tightness of 3m3/m2/hr is a necessary target before you even consider an MVHR system.

There are a few people who feel extremely strongly about MVHR only being employed below an air tightness figure of 1m3/m2/hr. Either way it is universally recognised that the more air tight the building is the more energy can be recovered and reused by the ventilation and heat recovery system.

Either way we are extremely pleased that our contractor has achieved there lowest ever air tightness figure on the Hassocks Sports Pavilion of 1.13m3/m2/hr. This will ensure that the building is healthy and energy efficient in terms of space heating for many years to come.

Achieved Ecohomes Very Good

Ecotecture Ltd are pleased to be able to offer Ecohomes and Code for Sustainable Homes assessments for designers and developers to ensure that their projects meet certain environmental credentials.

From Pre-Assessment to Post Construction we assist our clients by giving clear instructions regarding responsibilities for provision of evidence and lead them through the process of obtaining credits as quickly and cost effectively to achieve a low environmental impact building.

If you would like more information or assistance with either Ecohomes or Code for Sustainable Homes assessments, please don’t hesitate to contact the office on 01444 416745 where we can discuss further and provide a competitive quotation for this service.

In addition to Code and Ecohomes assessments we also provide services to building surveyors and architects to include vital information in there own drawing sets and specification documents, to ensure a smooth delivery of the assessment process. We specialise in taking the hassle out of the code!

The Plant Lock is seen as an experiment and is for use by the general public. It is planned to change the plants later in the year and we’ll see if it gets vandalised or not as time goes by. The idea is also to promote the idea of urban allotments, where we make better use of our built environment by growing our own food in small spaces. Part of ecotectures ethos is that sustainable buildings need to include areas that encourage sustainable lifestyles. Not always easy in a dense city environment.

The Town Council are also undertaking an audit of street furniture as part of the revised Forward plan for the town so if successful the Plant Lock could be seen in plenty of other places. The Town Council’s Mission statement aims to create a ‘Thriving Community, which will be an attractive, vibrant, sustainable and prosperous town’

In our picture here the Plant Lock is being planted up by Tom and Sam Saady-Gardiner. ‘It was fun to plant the herbs and things’ says Tom ‘We don’t have a garden here so I’m looking forward to planting vegetables in the spring’.

The local community have recently seen the formation of a Neighbourhood watch scheme so we’re hoping this will help. The Plant Lock can be seen outside the Ecotecture Offices in Sussex Road. Well we hope it can be seen still there – watch this space!

Plant Lock www.frontyardcompany.co.uk on loan from Haywards Heath Town Council
Plants donated by Urban Allotments www.urban-allotments.com
Drainage shingle and compost donated by www.King-Construction.co.uk
Planted by Ecotecture www.ecotecture.co.uk

@BanTheCavity has been set up to encourage debate over the use of typical UK construction method, the cavity wall.

We at Ecotecture will be uploading images and linking in articles which show the weak points of cavity wall construction. Some of the images will be from past projects that we have learnt from, other images will be of projects we stumble upon locally.

We have taken the pledge to never construct another building with a cavity wall construction (with the exception of repairitry works to existing properties). With the building regulations becoming more focused on energy reductions we feel that the wall holding the construction industry back, has a a cavity in it!

Please send us your images to include within our blogs and tweets, input on the topic is very much welcome.

Follow and comment on Twitter: @BanTheCavity
or discuss via Email: banthecavity@ecotecture.co.uk

The project is now up to ground floor slab level with the underfloor heating being cast in place within the structural deck that the “opdeck” system provides. This had to be installed before the exterior walls were in place to avoid the need for an additional screed, which would have impact on the programe of works and the budget of the project as a whole. This is also an opportunity to reduce the total quantity of concrete used in the construction process.

Another effect of the improved weather is the positive feedback the building is giving us during these early stages of construction. The building is a classic solar orientated design, and prior to the completion of the roof and the installation of the windows rooms in the core of the building at the lower ground floor are based on our own estimates about 2 degrees hotter than the exterior of the building. This shows clearly that the use of superior levels of insulation and locked in thermal mass are effecting the internal environment to a considerable extent. Once the building is sealed air tight and heat recovery and ventilation is introduced the positive effect on the internal environment will be amplified. Speaking with Antoine from Kithurst Builders the contractor of the project, we both feel confident that the large TV in the games room will provide most of the heat demand for the building. This is typical of passivhaus architecture, but it is unusual to see this effect before the windows have gone in! It is extremely exciting to see such an exemplar building coming together.

Particular attention will be paid over the next few days on the structure at the tips of the crescent. It is essential that the building maintains the sharp aesthetic in these locations whilst also achieving good thermal continuity. The Nudura ICF system allows the contractor to install the structure required within the depth structural concrete core of the with the interior and exterior surfaces being thermally broken with the EPS insulation / shuttering. A slimline fascia will be installed around the structural post to produce a sharp edge to the building, this fascia will be backfilled with PIR foam insulation to reduce the thermal bridging effect of the post in this location. More blogs to follow, If you would like to keep up with developments on this project and others like it, please click the subscribe via email button below.

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