British Homes Awards international competition for a developer house in a New Garden City- shortlisted finalist
Growing Home explores the conflict between accommodating cars in the design of new housing and the many benefits integrated landscaping offers both locally and globally. Garden spaces are created around the house intimately connected back to the rooms which place the householder in the natural world, while the planted front gardens encourage interaction with the wider Garden City community.
Today approximately 25% of homes in Britain with front gardens are completely paved over and nearly 33% of front gardens have no plants, according to research conducted on behalf of the Royal Horticultural Society.1 One of the main causes is the significant rise in car ownership which has seen many front gardens turned into parking spaces, often using impermeable materials, which is having an impact on the environment. Simultaneously, the interest in ‘grow your own’ and pressure on allotment provision has led to increased use of, usually back, garden as productive space.
Growing Home comprises a flexible, informal family home with four double bedrooms over three floors with an integrated double garage. The plan layout has been designed to allow the house to be built as a detached, semi-detached or terraced home. The requirement for a driveway in front of the garage effectively defines the position of the house set back on its plot, so Growing House uses this as an opportunity for defined spaces which both connect back to the house and out to the surrounding community. These encourage environmental control, biodiversity and social contact from the use of the whole house plot including front gardens, drives and upper roof terraces. The Ground Floor has an open plan kitchen/diner with views onto both the front and back gardens. Wide sliding doors connect through to the living room, with a full width folding/ sliding door onto the rear garden.
The back garden is configured as an extension of the ground floor living areas; with direct access from living room and kitchen/dining room, the functions of the house extend naturally into the garden. As the back garden is private, it also provides a safe external space for children and pets.
There is a fully planted roof, directly overlooked by two of the first floor bedrooms, designed as an intensive bio-diverse garden area and the entrance pergola/canopy is also planted as a low maintenance extensive roof. Gridded timber frames attached to the elevations (front and back) allow plants to climb from the roof areas, provide solar shading, increase privacy and encourage beneficial wildlife, including pollinating insects.
The front gardens are designed as productive green spaces. With a visual connection to the kitchen, each garden allows the creation of a kitchen garden, a small orchard or ornamental courtyard. The vehicular areas are disguised by the use of permeable paving and gravel, incorporating extensive low level planting. A covered bin/recycling store has roof planting, perhaps for kitchen herbs. Each garden is separated from the pedestrian access by a linear planted swale, which attenuates rainfall from roads and gardens. Additionally, these busy front gardens give neighbours the opportunity to meet to help build community spirit. Birds and bats are encouraged and accommodated in the nesting/roosting boxes incorporated within the chimney stacks.
Growing Home is designed to optimise daylight and sunshine into all main rooms, gardens and solar panels throughout the year over the roofs of the adjacent homes, maximising the effect of passive solar gain even in the winter months by careful siting of roofs and set-backs. The dual roof pitches to provide an optimal orientation for solar panels no matter what angle the houses are laid out on.
The design aims for a zero-carbon standard, using super insulation with mechanical ventilation with heat recovery in winter and natural ventilation in summer to give a total space heating demand of under 3000 kW/yr for the 165m2 house (plus garage), with passive stack effect ventilation up the central staircase enhancing summer cooling. Integrated photovoltaics and solar hot water heating are located on the south facing sloping roof. The main 8kW photovoltaic array is capable of providing over 5500 kW/yr in southern Britain, nearly equivalent to the total electric demand, and the solar hot water heating installation can provide up to 50% of the domestic hot water requirement.
A split air source heat pump provides the main space heating via underfloor heating in all rooms, zoned to allow the top floor to be unheated if not in use. There is the option to accommodate an energy ice store under the garage. The large areas of glazing and shallow rooms give high levels of daylighting to all areas reducing electric lighting, but to prevent overheating in summer the south facing upper floors have horizontal timber louvre shading.
Ultra-low water use fittings are specified, and rainwater is captured from each roof and stored under the garage for reuse in grey water applications such as WC flushing and watering the gardens. Electric charging ports for vehicles and stacked cycle storage are accommodated in the garage. A covered bin and recycling store, framed with hedging with incorporating an additional living roof area is located conveniently in the front garden.
The beneficial impact of vegetation upon the performance of building fabric in terms of aerial cooling through shading and evapotranspiration (to counteract ‘urban heat island’) and acting as insulation in the winter by reducing air movement over building fabric can also be achieved through careful integration of suitable planting.
Construction and technology
A ‘fabric first’ approach is adopted, using simple Aircrete blocks wrapped with insulation and breather membrane and overclad to achieve a super-insulated and extremely air-tight building despite the relatively large envelope to surface area ratio in a detached house. It also gives the possibility of different cladding types for different locations – brick, render and stone, timber boarding, copper, zinc, recycled plastic etc without affecting the underlying structure. In this instance, Growing Home is shown clad with brickwork and timber boarding.
Growing Home comprises simple masonry crosswall construction with short span lightweight concrete floor slabs, suitable for underfloor heating and providing thermal mass. Extensive wireways for ‘smart home’ technologies are incorporated in the linings of the walls and partitions.
Growing Home has been designed to use the same standard construction methods as large housebuilders with a standard plot and traditional street layout. It could be built for a similar cost and be a genuine alternative to current speculative homes.
1 ‘Everything not so rosy in the Front Garden warns organiser of world famous RHS Chelsea Flower Show’, www.rhs.org, 18 May 2015