We are delighted to say that ‘The Warren’ was awarded a runners-up position in the Sustainable Project of the Year at this weeks Graphisoft Awards.

Overview & Project Brief

The primary objective for the ‘Warren’ was to achieve exemplar design quality for a new dwelling located in open countryside. 

The Client’s brief defined clear targets for both design quality and a lifestyle, fully integrated within a highly sustainable building fabric with an overarching requirement for the dwelling to demonstrate and utilise low-carbon technologies.

Being located outside of the formal village boundary of Bitteswell, the Planning System would ordinarily refuse residential applications except in exceptional circumstances. In order to be successful, the project would therefore have to demonstrate outstanding design, innovation and technical performance to be considered favourably under the more onerous policies underpinning the Paragraph 55 Approval route that sets a clear requirement for high-quality innovative design and sustainable development and all criteria must be met.

After a considerable amount of design development and technical advancement, Planning Approval was ultimately granted in January 2017.

Design

The Warren is a large site formed in a triangular shape, with narrowest point towards the Southern tip where a singular point of access from Ashby Lane is possible. As a former paddock, the land benefits from established boundaries on both East & West sides with tree lined hedgerows, forming the distinctive rural nature of the site. 

Given the shape of the site, the dwelling was located towards the Northern quarter of the site in order to maximise the footprint and have unencumbered solar potential. 

A two-storey dwelling emerged from the initial design sketches, with a ‘T’ shape configuration, providing a large open plan design at ground floor, with sleeping accommodation at the first floor contributing to creating an impressive family dwelling in a contemporary form.

Extensive landscape and visual studies were carried out as part of the design development to carefully position the dwelling to maximise important long-range views out of the site and similarly mitigate views into the site and of the dwelling itself so as not to distract from the landscaped setting. 

The design incorporates a combination of flat and pitched roof areas enabling an array of solar thermal panels, designed as a fundamental part of the heating and energy to be integrated as part of an innovative inter-seasonal solar thermal energy store, located below the foundations / floor slab of the dwelling. 

High quality design and use of materials is evident throughout. 

The final build was successful in achieving an EPC rating of A+ 97% with potential to increase to 104% efficiency. This was primarily achieved by a “fabric first” approach to the building envelope and renewable heating and energy storage integrated into the design.

Challenges

The overarching challenge for this project was achieving Planning Approval, due to the restrictive planning policies protecting development in a rural setting. As such the design team worked closely to undertake extensive consultation with the Local Authority’s Planning Department, plus their appointed external Design Review Panel, who provided independent design advice.

After an extensive cyclical process of design development and review surrounding the architectural, sustainability and landscape designs, the Design Review Panel finally gave a positive recommendation to the Local Authority, enabling Planning Approval to be granted.

The subsequent technical challenges of delivering the project were significant and complex. The bespoke nature of the design meant that all construction details were non-standard and required considerable design & co-ordination. From the outset the scheme incorporated innovative design and technical solutions to meet the targets set in the early stages for a low-carbon, functional family dwelling. 

brp architects worked closely with Caplin Homes, a local firm specialising in low to zero carbon construction to develop the technical aspects of the design, incorporating solar thermal heating and energy storage. 

During the early stages of construction in October 2019, adverse weather and the global Covid-19 pandemic led to a number of construction challenges particularly using a lightweight foundation solution (see next section) in a groundwater flooded site. These were well-managed by close collaboration and high levels of communication to resolve issues as they arose.

Materials & Technologies

The Warren incorporates technically advanced construction processes and materials to ensure the sustainability targets are met. 

The substructures for the house are a Swedish system incorporating a combined foundation, floor slab and underfloor heating system within a single polystyrene-based product. This time-saving construction is highly innovative and quick, providing programme benefits. 

The superstructure is a highly insulated, airtight, timber frame construction. This was manufactured off site, enabling speed of construction and rapid weatherproofing of the shell, completed with high performance window and doors providing stunning design and considerable natural light to the interiors. 

Space heating for the dwelling is provided using summertime energy captured via solar thermal panels that is stored in an earth energy bank below the foundations for use in use in the winter months for space heating and hot water via heat pumps.

Solar energy is also converted via photovoltaics reducing electrical reliance on the consumption from the national grid. 

Internally the dwelling incorporates new technologies, such as energy efficient demand Mechanical ventilation heating and recovery system and contains features such as centrally controlled lighting, heating, security, fire and entertainment systems. 

Computer modelling – ARCHICAD features

Due to the pandemic the client was in the Middle East for much of the project so we relied heavily on the BIMx application to communicate and interrogate the design with the client, which proved an invaluable resource. We utilised the latest Archicad package to fully model the scheme to present, test and challenge all aspects of the design.