This project investigates the effects of future climate change on a large social housing development in Liverpool. The development itself involves the design of over 100 houses on a brownfield site within a masterplan of around 240 new houses.
The study explores the opportunities and constraints of using industrialised timber building systems in the context of climate change and the client’s aim to deliver high quality, affordable housing. It considers innovative volumetric modular systems with best practice timber frame and will seek to develop both concepts in designing for climate change adaptation.
Assessment was made not only of the performance of the building systems, but also of the effect of siting, shading and external envelope design on thermal performance. Alternative Masterplan studies also consider the effects of the urban layout on flood risk, and wind patterns.
Further project details
1. What approach did you take in assessing risks and identifying adaptation measures to mitigate the risks?
The study is approximately 95 per cent complete subject only to submission of final report. Initial research stages focussed on:
- Analysis of projected future weather data.
- Psychrometric charts to assess cooling strategies.
- Comparative thermal modelling of a baseline scheme.
- Future energy modelling (including potential air conditioning loads).
- Review of performance and risks of baseline masterplan for ground stability, flooding and wind.
- Assessment of superstructure, foundations and site stability issues on designs.
- Review of timber construction systems market and appraisal of selected systems.
- Climate change risk assessment for a baseline scheme with a focus on high impact risks – the ‘crash test’.
The project followed two alternative design adaptation strategies:
- Proposals for ‘near to market’ adaptations, many of which are now incorporated in the approved scheme and tender proposals.
- Proposals for a more idealised ‘future market’ solution. This has been developed into a concept design for a climate resilient industrialised housing product called ‘IDEAhaus’.
2. How have you communicated the risks and recommendations with your client? What methods worked well?
- Client involvement in preparing the competition bid and in design team meetings from the start – essential for two-way understanding.
- Client involvement in setting appraisal criteria and risk assessment.
- Clear presentation of technical data, e.g. extent of overheating modelled in baseline scheme houses using projected future weather sets.
- Meeting with the client’s government funding body, the HCA to win political support for the study.
- Summary presentation to whole client development team on this study and a previous D4FC study.
3. What tools have you used to assess overheating and flood risks?
- University of Exeter ‘Prometheus’ database of future climate models.
- IES software – thermal modelling.
- Climate Consultant 5.0 – weather modelling including Psychrometric charts.
- Sefaira Concept – energy modelling with projected weather files (including potential air conditioning loads).
- Sketch Up – masterplan modelling.
4. What has the client agreed to implement as a result of your adaptation work?
A longlist of 118 specific recommendations were made to adapt the existing pre-planning design. Of these, a total shortlist of 37 items have been accepted by the client for inclusion in the approved planning scheme and tender stage designs and specifications.
Examples of passive cooling measures adopted include:
- adding rooflights over stairwells for improved ventilation
- higher bedroom ceilings to increase stratification of air
- blockwork construction for thermal mass
- appropriate tree planting for shade to houses and external spaces.
Examples of flood resistant measures adopted include:
- use of green space, site levels and swales to attenuate and relocate flood risk
- raise internal services to 750 mm AFFL
- flood resistant construction and materials
- no return valves to sewers
- increased gutter and drain sizes.
A further shortlist of 20 potential future adaptations has been identified which largely involve retrofit or replacement of features due to current financial constraints.
The client is very interested in the study and how it could be applied to this project and at a policy level it will inform their strategy for future construction and setting design performance requirements they are interested in possible long-term relationships with building system manufacturers to increase the efficiency of their housing delivery.
There are recognised budgetary constraints in this sector and clear benefits would normally be demonstrated within a 30 year financial ‘horizon’ for the project and set against risks within that period or otherwise be no or low cost solutions. However, there have also been some discussions around the way both energy/carbon saving measures and climate resilient features are funded and whether new business cases could be developed to increase their viability.
As anticipated, adaptations accepted on this development are from the ‘near to market’ solutions offered.
The IDEAhaus design concept developed for the ‘future market’ options was presented at the influential Passive Low Energy Architecture (PLEA2013) conference in Munich which awarded it Best Paper for research. This concept has now been awarded a TSB Smart Fund grant to carry out proof of market research by new business, Green Triangle Studio, in 2014.
5. What were the major challenges so far in doing this adaptation work?
The ‘Prometheus’ weather files are very useful but still project a smoothed picture of the future weather and do not describe more extreme events such as storms with maximum gust speeds and a future 1:100 year flood which are important design criteria. The team have had to invest in additional research and supposition to explore these risks further.
The housing sector has little experience of thermal modelling or rainfall analysis and its view of climate change risk assessment is as varied as that of the public at large. There would be greater likelihood of more fundamental design recommendations being implemented if the research and option appraisal stages were more in advance of the client’s delivery programme, or if local ‘rules of thumb’ could be developed to establish new baseline assumptions about building performance.
6. What advice would you give others undertaking adaptation strategies?
- Start research and option appraisal as early as possible in order to be ahead of the development timetable and influence the project briefing.
- Engage the client fully in the risk assessment process.
- Present risk and performance appraisals clearly to raise client awareness.
- Relate performance evaluation to the client’s economic ‘horizon’.
- Understand that the building must perform in response to ‘weather’ not ‘climate’.
- Understand that weather projections offer a range of possibilities and try to allow for future adaptability – ‘long life, loose fit’.