Case Studies

Project Overview

City Hall, Bristol is a Grade II* building commissioned by Bristol City Council as its corporate HQ in the 1930‟s. It has been comprehensively remodelled internally to create a contemporary and agile working environment for staff and partner organisations with increased public access.

Public access to the building is increased with refurbishment to the council chamber, conference hall and committee rooms. The heritage status of the building has been respected by the designers: sensitively used as a back-drop to create a vibrant working environment with enhanced public facing spaces.

The former Cash Hall has been restored to its original volume and is now the heart of the working environment containing a coffee bar, auditorium and spaces for informal and formal meetings between both council employees and visitors. Originally serving approx 600 employees it now serves approx 2000, a 300% increase in utilisation.

The Council were not only able to remain in their original building, but the upgrade was completed on time and on budget to reflect the requirements of delivering services to the City of Bristol in the 21st Century.

Best Practice

Careful project planning and good regular communications by the team from start to finish has resulted in a project that was completed on time and to budget with the highest quality possible. The Client was as able to occupy some areas in advance. A regular review of programme and progress was carried out throughout the project to ensure that all project changes were smoothly incorporated into the programme by Contractor driven decision dates, to allow for adequate lead times for designs, procurement and installations.

Team work: was a key driver in the success of the project which is fundamental to a project of this size, complexity and heritage status. Regular commercial meetings and cost review allowed for the budget to be controlled and client informed on decisions. The project was successfully completed on time, achieving the Contractor‟s ethos of „Perfect Delivery‟ with “snag free” at handover as result of a positive team work approach to allow for careful planning to ensure adequate time was allowed for the safe completion of the works for the agreed completion date.

Environmental Impact: A new LED lighting raft incorporating intelligent dimming controls was installed to drastically reduce the lighting energy consumption. Further works included new air handling units incorporating heat recovery replacing existing inefficient belt-driven fans. Electric resistive heating replaced with low temp, hot water radiators. Gas boilers were replaced with high efficiency condensing modules. Additional temperature and C02 sensors were installed for monitoring and control purposes and where applicable control logic was reprogrammed to react to temperature/C02 levels. It was possible to retain the existing natural ventilation strategy in the office spaces thanks to detailed thermal modelling. External windows were refurbished to improve airtightness but because of the heritage listing of the building significant thermal improvement of the external envelope was not practical. As part of the strip-out over 3,100 items were handled, of which 82% were redistributed to good causes, 17% recycled, 0 waste to landfill. Current modelling indicates that annual savings in energy costs will in the region of £73k per annum and carbon savings of 405tC02/year. The building will connect to a proposed district heating system planned in the city centre.

Heritage

The biggest challenge architecturally was to balance the requirements to respect the heritage significance of the building reflected in its Grade II* listing with the requirements of a 21st century working environment. In particular the fire strategy was an engineered solution given the increased populations involved and the heritage constraints in remodelling stair cores. City Hall is a building of significant heritage value, largely complete in terms of layout, fabric and original fittings. The design solution involved close engagement with the council’s Conservation Officer, Historic England and the 20th Century Society to develop a solution that satisfied all stakeholders. The solution involves a combination of restoration of key heritage items principally on the First Floor and new construction that respects the principles and quality of the original design whilst clearly being a modern intervention. A number of the new additions are reversible.