The project is looking at the impacts of design, services and the public realm on the resilience of new timber-framed homes to climate change. The key climate change risks that are being explored are:
- thermal comfort, internal and external
- surface water flooding
- clay soils with a high shrink-swell potential
- water availability for domestic use.
The project aims to:
- recognise the uncertainty in the severity of climate change impacts
- be sensitive to commercial realities and to give confidence in the costs and benefits of the strategy
- make use of adaptation measures that result in a wider positive benefits for the development.
The design of adaptation measures along with evidence of their costs and benefits will help the developer to take the impacts of climate change into account and will provide valuable lessons for the Government and the wider construction industry.
Further project details
1. What approach did you take in assessing risks and identifying adaptation measures to mitigate the risks?
We have used a risk-based methodology to identify the most important risks to mitigate through designs.
We recognise the uncertainty implicit in future emissions trajectories and in the climate projections. Over-adaptation as well as early adaptation should be avoided. We are aiming to incorporate the flexibility needed to respond to new information and increasing certainty over time .
At the same time several low regret measures are best designed in from day one. It is important that these are identified.
2. How have you communicated the risks and recommendations with your client? What methods worked well?
Our client has a good understanding of climate change issues and has contributed to our analysis of site specific and construction risks.
We have been keeping the client up-to-date with our emerging findings by circulating meeting minutes. We will be engaging with them in forming the strategy, and in developing guidance for the wider industry through a series of workshops.
3. What tools have you used to assess overheating and flood risks?
We are using IES with the Prometheus weather tapes produced by Exeter University to build thermal models for three house types and to assess changes to the microclimate from increased green cover. The findings are sensitive to occupancy assumptions and we will be testing these to better understand actual building performance:
- during periods of overheating, are there cooler spaces in the home that can act as a refuge?
- will the home be comfortable for families with different lifestyles?
- what do alternative metrics of thermal comfort show?
We are also using the Met Office’s projections of changes in the frequency of extreme rainfall events with Micro Drainage modeling software to evaluate the existing drainage design and the appropriateness of the Environment Agency’s current guidance on flood risk.
4. What has the client agreed to implement as a result of your adaptation work?
We have not reached this stage of the project as the options appraisal and cost assessment have not been completed.
5. What were the major challenges so far in doing this adaptation work?
The masterplan layout and other features of the development cannot be altered at this stage, limiting some types of intervention.
While there are clear adaptation (and wider) benefits to integrating additional green infrastructure into the masterplan, there are a number of legitimate concerns which we are trying to address:
- potential conflicts with Secured by Design criteria
- development density – developing street sections which include trees and other services without decreasing development density
- local authority commuted sums as a disincentive.
Ensuring that there is a plan for managing and maintaining the adaptation measures upon which the whole development is dependant:
- bringing flooding infrastructure into the public realm
- community ownership and governance issues.
Timber framed buildings have low embodied energy but they are inherently lightweight, making them more vulnerable to overheating.
6. What advice would you give others undertaking adaptation strategies?
The strategy needs to be realistic about what measures are likely to be commercially viable for the developer.
The strategy should focus on low cost, low regret measures that reduce the cost of future adaptations. Also, measures that improve the marketability of quality of the development in other ways should be prioritised.