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Trowbridge County Hall

The original County Hall was of traditional stone construction built circa 1935 with timber sash windows and cellular bespoke design. It contains approximately 15 000 m² of office space including committee rooms and member rooms.

The four storey County Hall has a 7 m width floor plan on the east and west wing and a 16 m width floor plan for the main section up to the second floor with a 7 m width for the main section on the third floor. The County Hall is on a main road and near a train line where acoustic issues are present. A major extension to the County Hall was completed in the 1970s and consists of a four storey office block. It is constructed from a concrete frame with aluminium windows and is mostly open plan. The extension has a deep floor plan of around 30 m².

Further details

1. What approach did you take in assessing risks and identifying adaptation measures to mitigate the risks?

Rsks were assessed using a rating of probability and impact resulting in a rating between low and extreme.

Where possible risks were quantified in terms of their impact on the building under different climate scenarios.

Some adaptation ideas were generated at the CCA focus session held with the client and design team early in the process. Additional ideas were generated as the project progressed by the CCA team.

2. How have you communicated the risks and recommendations with your client? What methods worked well?

We have provided results both in report and presentation formats, both of which have contained sketches to communicate design concepts and graphs to communicate the outcomes of design modelling.

We have found with the bulk of material generated that the presentations have been more successful than the reports owing to the length and content of the reports.

Trowbridge County Hall sketch

3. What tools have you used to assess overheating and flood risks?

We have used TAS modelling software with weather data generated by the Prometheus project at the University of Exeter to assess overheating.

Flood risks used a range of published resources including the IPCC technical paper on climate change and water, UKCP09 climate projections and Climate Southwest.

4. What has the client agreed to implement as a result of your adaptation work?

The client has agreed to the following modifications and investigations:

  • design building fabric to exposure category 4
  • assess structural strength of wall ties
  • rainwater recycling for MECH building
  • water use awareness campaign
  • relocation of some equipment from basement
  • relocation of office space from basement.

Other strategies under consideration:

  • greywater recycling for OCH building
  • more tree planting.

5. What were the major challenges so far in doing this adaptation work?

We believe to realise value for the client there needs to be an emphasis on being able to quantify the impact of climate change scenarios to understand whether immediate or delayed investment is necessary. This can be done with some certainty for risks to thermal comfort however construction and water risks require additional support to enable quantification.

There is a wide range of potential climate change impacts. The challenge is to direct the funding to areas that will yield the most benefit for the client in terms of increasing asset resilience to climate change effects.

6. What advice would you give others undertaking adaptation strategies?

Get early client engagement with a climate change adaptation focus workshop with the aim to:

  • educate the client on the range of CCA issues
  • highlight design opportunities
  • help narrow the focus of the study
  • be systematic and careful to keep the focus of the study on genuine climate change adaptation issues and not just general design issues.