PROJECTS | THE HOME FOR ALL SEASONS
The WINNING entry in the Sunday Times & British Homes Awards 'Resilient Home' Design Competition, designed in collaboration with JTP.
'The 'Home for All Seasons' is designed to take extreme weather in its stride - a place to live in comfort throughout the year. Whether torrential rain causes flooding, blazing sun causes a heatwave or it’s so cold that there’s a big freeze, the 'Home for All Seasons' will keep you safe and sound.'
This future-proof design provides protection, comfort and independence to residents through an approach of resilience, rather than resistance, to the very real issue of extreme weather conditions. It works inline with the principles of good place-making and rather than seeing 'resilience' as a compromise uses it as a feature to enhance the way in which residents live in and enjoy their homes. As a result those living in the 'Home for All Seasons' have peace of mind in the knowledge that their home can be quickly and easily adjusted to cope with the wide range of challenges the future holds.
The 10 Principles of the 'Home for All Seasons'
1. Habitable zones are positioned on the first floor level and above to ensure a future proof, high flood datum design. This strategy avoids reliance on temporary add on measures for flood protection.
2. The ground floor ‘garden room’ zone is a flood resilient, multi-use space that can be quickly adapted and cleaned post flood.
3. The elevated ‘causeway’ at first floor level provides safe access and egress during a flood event and reduces the demand on emergency services.
4. Water and power utilities are elevated to first floor level to enable continuity of services during a flood event.
5. The buildings' minimal hardstanding 'footprint’ provides space for the integration of SuDs / swales and avoids displacing water to surrounding developments.
6. House design is suited to compact plot with reduced back-to-back distances. This means a density of 60 dwellings per hectare can be achieved.
7. The building form is designed to encourage passive stack ventilation effect with air drawn in through the high thermal mass ground floor zone
8. Thick and continuous super insulated envelope – ensures comfort in extreme cold.
9. Roof orientation designed to support on-site energy generation
10. The core house plan can be adapted to suit the changing needs of the homeowner and works for a range of different house types and layouts.
RESILIENCE TO: FLOODING
One of the main strengths of the flood risk management strategy in this scheme is that it can be applied and adapted to suit the diverse range of flood risk contexts found in upper, middle and lower catchment zones. For upper catchment areas (where DEFRA's LifE project mantra of ‘Let it Slow’ is recommended), both SuDs and swales can be incorporated into the layout of the development to help slow down and buffer the movement of water through the site. Flood water storage capacity is provided by permeable paving, flood storage crates, green roofs and minimal building footprints to ensure a large porous surface area for absorption of water into the ground plane. In mid and lower catchment zones (where the mantras of ‘Let it flow’ and ‘Let it go’ are recommended), the porous ground floor configuration provides unobstructed channels for through flow of water, thereby avoiding backlogging and displacement of water to surrounding developments.
The flood risk management strategy for the scheme has been designed and configured upon the principles of flood resilience rather than resistance. There has been a deliberate avoidance of incorporating resistance based add on measures for flood protection (such as temporary door guards, which need to be deployed and fitted by occupants) or automated barriers that require regular maintenance and are not appropriate for use in all flood risk contexts. Instead, a strategy for flood resilience has been embedded in the scheme through the considered configuration of habitable zones and access/egress routes. The intention is that by positioning the living zone, utilities and walkway at first floor level the occupants of this scheme would not experience a state of emergency during a flood or extreme weather event but rather a brief but unobtrusive state-change in how they move around and inhabit their homes.
One way of understanding the value of this approach is to consider how it compares to consequences experienced when traditional development schemes flood. Current strategies for managing flood risk to homeowners during an event are often reactive and require external support from emergency services. As a result, residents may have to be rescued from their homes, displaced for months, and endure lengthy periods of loss adjusting and reconstruction processes. In contrast however, in the 'Home for all Seasons’, when a flood warning is issued, residents are encouraged to move their vehicles to designated safe zones nearby, from which they can then walk safely back to their homes. Instead of being relocated, people are encouraged to continue occupying their homes, and are safe to move around the development, perhaps checking on their neighbours to see if they need any help. Recovery or repair work to home is minimal (for example, hosing down and cleaning the ground floor garden room zone) and the elevated power and water utilities at first floor level ensure continuity of services; before, during and after a flood event. This scheme been designed to ensure long-term safety from flood risk whilst also minimising the need for loss adjusting after a flood event.
RESILIENCE TO: EXTREME HEAT
To avoid the threat of overheating, this proposal incorporates a number of strategies. Firstly, the building is configured to be mixed mode, with its form design to provide shade during the summer months and use the stack effect to pull cool air from shaded ground floor zone. Secondly, the high thermal mass of the ground floor ‘garden room’ acts as a labyrinth, pre-cooling the air before it enters the living area on the first floor and moves up through the natural ventilation chimney stack (that incorporates a heat exchanger) on the roof ridge. Finally, adjustable horizontal louvers and solar thermal tubes provide shade to the glazed side façade, thereby minimising solar gain.
RESILIENCE TO: EXTREME COLD
The design proposal embeds passive design principles and would seek to achieve Passive house standard with a space heating demand of up to 15kWh/m2 and a primary heat demand of up to 120kWh/m2a.Key to retaining a comfortable and consistent temperature inside the home during periods of extreme cold, the scheme includes:
· Air tightness of <0.6 at 50Pa through thorough design and detailing
· Super insulated closed panel timber frame construction system with U-values of 0.15W/m2K
· Triple glazed windows with insulated frames with U value of 0.8W/m2K.
· Heat recovery from exhaust air from bathrooms and kitchens.
RESILIENCE TO: SOCIETAL CHANGES
The core house plan is easy to expand and adapt so that as families grow and populations continue to increase the residents can amend the building layout to suit their needs. This loose fit approach also provides flexibility in the house type, such that homes can be split into flats or extended over time and even space for growing food on site.
RESILIENCE TO: ECONOMIC CHANGES
The scheme has been designed to be future proof and resilient to economic changes such as rising energy costs. Integrated PV on roof can be used for micro power generation with space allocated in the floor plan for a home power storage unit enabling occupants to sell back to or be off the grid. Heating demand is minimal due to passivehaus specification throughout with low energy fittings and fixtures ensuring the energy demand remains low. The future energy demand for cooling is also minimal as a result of the natural ventilation strategy throughout the home. The flood strategy in this scheme is intended to help provide homeowners with financial independence from the need to claim for flood risk insurance and instead encourage simple, safe, and efficient repair and reinstatement after a flood event.
Affordability in construction costs is achieved through a compact regular building form and simple timber frame system with regular roof trusses that can be mass produced. The system makes use of short, affordable, lower grade sections of timber that can be sourced and manufactured locally. It also includes simple fenestration and smaller glazing panels and avoids the use of moving parts, such as flexible services or hydraulic rams which are not appropriate in all flood risk contexts.
LIFECYCLE COST ANALYSIS & DURABILITY
The building design incorporates long life, durable materials that require little maintenance and on the event of failure are easily repairable. The dwellings are designed to require minimal maintenance; they will age naturally and retain their distinctive appearance over many years. Detailing and in particular the movement of water over the dwelling has been considered and integrated from the outset. The costs associated with recovery after a flood event have also been considered, with the resilient ground floor zone reducing the need for expensive insurance claims or reconstruction.
Achieving resilience does not have to come at the detriment of good design. It can instead be used as a mechanism to actively enhance the quality of placemaking in communities. The house design in the 'Home for All Seasons’ scheme not only provides resilient strategy but also creates attractive and safe public realm. Compact plot layouts are complemented by generous street dimensions, with green space used as an active ingredient in the flood risk management strategy (SuDs, swales) whilst providing both shade and cooling. This scheme looks to encourage a change in how risk is perceived, making living with uncertainty a more enriching and positive experience.