Brighton, East Sussex
Project: Eco refurbishment of office block
Architect & Principle Designer: BBM Sustainable Design Ltd
Project Manager / Quantity Surveyor : MacConvilles
Structural Engineer: HOP Engineers
Contractor: Facade Concepts
Contract Sum: £1.1 Million
In 2017 BBM completed a major eco-refurbishment of an iconic 1960’s six storey concrete frame office building in central Brighton.
This project known as Community Base houses over 35 community and charitable organisations. Sited along Queen’s Road, one of Brighton’s busiest streets just South from the mainline station, this project presented the team with a number of major challenges, not least that of how to find an economic way of re-cladding the building which had severe concrete cancer within the 1960’s pre-cast concrete panels of the main elevations. Our clients also wanted the works to be completed without tenants having to leave the property. Brighton & hove City Planners were also looking for the architectural handling to be kept broadly the same as the original in terms of the modelling the bays. However, the site is on the edge of a conservation area so it was important to present a proposal with high aesthetic ambitions.
Working in conjunction with specialist contractors Facade, BBM developed an innovative over-cladding solution that addressed the immediate problem of the failing concrete structure and added value by improving both the thermal performance of the building and the tenant’s internal environment. This was achieved while creating a beautiful facade which was inspired by the elegant curtain wall of William Crabtree’s Peter Jones Building off Sloane Square. Crucially the detailing needed to allow the pre-fabricated aluminium cladding panels and vertical spandrels to accommodate a new layer of external wall insulation isolating the remaining concrete frame from the extremities of the external environment. All this has been achieved with minimal interruption to the tenant’s operations, at a very low cost to the clients, while extending the life of the building ensuring the long-term future of the organisation which in turn allows the charitable sector tenants to continue their work for the vulnerable. It is also the first phase of a longer term environmental strategy for the building that will in future see the replacement of the inefficient outdated night storage heating system, the insulation and replacement of the roof covering, the installation of renewable energy including PV panels.
– How to refurbish the elevations
– How to deliver best value to a charity with limited financial resources.
– How to ensure the continued operation of the building with some tenants more sensitive to noise and disruption (eg Translation services) than others.
– Reviewing the proposed solution in the context of other priority maintenance issues.
– Exploit any potential for reducing heating bills and improve internal comfort conditions.
– Overcladding the building with alternative materials which closely matched the original architectural landscape which was a requirement of the planning department. Our clients are a charitable organisation and the rents they charge are affordable. Cost-effective and efficient design solutions were a priority.
With limited financial resources it was necessary to find a long-term solution that was both cost effective and allowed the building to continue to operate. The solution was to commission an energy analysis and a thermal model of the whole building to establish suitable options and priorities. This allowed the Design Team to run a number of different design models demonstrating the benefits of external wall insulation, double glazing, roof insulation, solar thermal and solar pv. This was all supported by cost benefit analysis.
The outcome recommended two options be considered both incorporating roof insulation, PV panels and triple glazed windows and one recommending all the above plus external wall insulation. The recommendations were broken down into affordable phases, the first phase addressing the immediate concern with the façade.
An insulation and single skin aluminium cladding system including replacement windows (Phase 1) was designed incoperating the thermal model. Subsequent phases will address roof insulation and PV panels (Phase 2) and heating system (Phase 3). To maximise value for money and ensure the scheme was affordable the unusual decision was taken to tender the works direct to cladding sub-contractors rather than through a main contractor.
Care was needed to ensure cladding sub-contractors understood their responsibilities and had allowed for suitable supervision, welfare, coordination etc. The result was tenders that were approximately 15% lower and an affordable scheme.
The outcome has ensured:
– Extended building lifespan
– Improved U values
– Improved Internal environment both thermally and acoustically
– Lower heating bills
– Happy tenants = Happy client
– Hugely improved aesthetic appearance of this significant Brighton landmark.
BBM have undertaken an initial post occupancy evaluation which was timed to reflect on the experience of the site works as well as the first period of use through the late summer of 2017 through to late spring 2018. We have obtained one quarter’s worth of energy bills from the client and calculated a net reduction in energy usage of 20%.
BBM issued a primer with a series of questions ahead of a workshop session held at Community Base where the Client team and tenants were invited to attend. The discussions covered aspects of the tenants’ experiences with the build phase and what issues arose for the Contractor. The overall comments on the completed works and the improvements effected has all been extremely positive. We also gained a number of illuminating testimonials:
“It is a huge relief not to need to have a hot water bottle and blanket while trying to work”
“Spring/Autumn – The building performs well, the temperature is consistent in conjection with the heating system despite changes in temperature externally”
“Summer – As with spring/autumn the air flow is much better. Before the works the offices were far too hot compounded by the fact that many windows could not open”
“Winter – Previously the offices were very cold during the winter and extra oil heaters were needed to even keep a low temperature and the windows were draughty. We have not needed to use oil heaters as much (mainly due to our own system of storage heaters not being fit for purpose), there are now no draughts and the new windows are robust”