Building control: conservation
Working in complete harmony
26 January 2012
Andy Foolkes discusses the evolution of a centuries-old building
Chetham’s School of Music is a co-educational independent music school in Manchester that cultivates talented music students from around the globe. The largest music school in the UK, and located in Manchester’s medieval quarter, the original buildings date back to the early 15th century when it was built as accommodation for the warden and fellows of the Collegiate Church of Manchester, now Manchester Cathedral. It was known as Church House hundreds of years after priests left the site during the Reformation. Only a few establishments of this type have survived, and this is the best and most complete example in the country. Church House is on the site of the former manor house of the lords of the manor, with the boundaries to the North West, the River Irk and Irwell, fortifying the occupant’s ecclesiastical and political power.
The Church House building was bought in the mid-17th century by a local merchant, Sir Humphrey Chetham, who adapted it for use as a school and a public library. Towards the end of his life, Sir Humphrey accrued debts: worried that Parliament would take his money when he died, he established both this school and Chetham’s Hospital as his legacy.
This combination of 15th century building and 17th century fittings is very rare and the library collections and original furnishings are of national importance. Other important architectural additions include a schoolroom designed by Alfred Waterhouse, an architect most notably associated with Victorian Gothic Revival architecture and designer of the nearby Manchester Town Hall and London’s Natural History Museum. The public library, the oldest in the English-speaking world, has an exceptional collection of documents dating back to the 1600s. Famous students who have studied there include Celia Fiennes, Daniel Defoe and Karl Marx.
Chetham’s august reputation means it continually needs to evolve. A triangular-shaped school is being built on an adjacent site, which will incorporate music and academic teaching facilities; a 400-seat concert hall with an additional 100-seat recital hall, box office, foyer, and bar area, with a bridge linking it to the existing building.
Designing and constructing a scheme that complemented the school’s historical architecture and enhanced its international status fell to Stephenson Bell Architects as principal architect, Sir Robert McAlpine as principal contractor and Drivers Jonas Deloitte as project managers. Butler & Young’s national coverage means it can work on developments throughout England and Wales, but this scheme was project-managed and site-inspected by its North West office.
Works started in earnest in late April 2010 and from the outset constructing a building with a footprint that took up the majority of the site without impacting on the everyday operations of the existing school meant a very claustrophobic experience for the construction team. A Victorian culvert with a diameter of 4m running through the site and a major power supply for the adjacent Victoria Railway Station added to these constraints. The presence of two permanent tower cranes and a central concrete tower were invaluable.
A combination of piled and reinforced foundations was used; the structural frame is predominantly reinforced concrete with both traditional and precast brickwork panels to the perimeter. One of the most striking design features is the substantial eccentric projection and bridge link: this has been proved to work by structural engineers Price & Myers and is a cantilever, supported by substantial 1.5m deep horizontal elements. The deep horizontal components when viewed against the slender horizontal columns seem incongruous, but the columns have been designed to give minimal support and comply with Part A.
Butler & Young’s North West office’s involvement began around four years ago with initial advice relating to the imminent changes to the 2002 iteration of AD L and the implications this may have on the scheme, which has been funded privately and publicly from the Northwest Regional Development Agency and the Department for Education, meaning that any change to these variables may compromise the project’s viability. The client wanted a sustainable and iconic building: the development is set to achieve a BREEAM ‘very good’ rating, with additional provisions to achieve ‘excellent’ (budget permitting).
The building will primarily be used for music recitals, and a particular client requirement was a high degree of sound insulation between the 115 music rooms and other curriculum teaching spaces. Ably guided by Arup, each music room has an individual ‘floating floor’ cast within the structural floor slab, along with other measures such as highdensity block and individually designed studwork elements to maximise sound attenuation.
The sound reduction within the 400-seat concert hall and 100-seat recital hall has been designed on the ‘box within a box’ concept, using the airspace between and the density of the two ‘skins’: the reinforced concrete structural frame to the perimeter provides the outer box and the inner box is only supported by columns which are independent of the outer box floor slab.
It’s amazing to think that a building of some sort has been on this site since around 1421
A building crafted to be both architecturally striking and provide the necessary facilities requires innovative design and presented several fire safety challenges. As the height of the uppermost floor was greater than 18m, Building Bulletin 100 guidance wasn’t applicable, but consideration was given to the document’s ethos, for example, the protection of irreplaceable assets such as pupils’ coursework, expensive musical and ICT equipment.
The school has good links with many nearby orchestras, including the Hallé, and the concert hall will be used for public performances. The potential for various areas, and consequently escape routes, to be inaccessible meant many meetings with all stakeholders to ensure a safe design. Butler & Young has staff with particular expertise who provided advice on the Licensing Act and the Regulatory Reform (Fire Safety) Order.
The architect wanted an uncluttered, open-design philosophy throughout, resulting in occupants having to travel within 4.5m of the edge of the balconies within the five-storey central atrium. No cross-corridor doors have been provided to certain areas and a deterministic approach was employed by fire engineers, Norman Disney & Young, to demonstrate compliance with AD B. The rationale for the design was based on reducing concentration of smoke to ensure tenable conditions for occupants as they move to a place of safety.
Fire safety engineering techniques have been employed when looking at access and facilities for the fire service. A comparative study was carried out and the review demonstrated that the removal of a firefighting shaft, based on the realistic deployment of the attending fire crew, would be comparable to the B5 requirements.
The school’s work in the wider community has been reflected by an outreach centre at the corner of the site, which has been designed to ensure maximum inclusivity. A major challenge has been negotiation with the design team regarding access to the facility: the ‘infill’ nature of the building and the extreme change in level between the Hunts Bank and Station Approach have necessitated a balance between acceptable levels of accessibility and existing site constraints. Butler & Young North West was able to offer advice concerning The Equality Act and its resident access consultant has been instrumental in minimising compliance risk.
Inside the building, serious consideration has been given to achieving a balance between providing big, heavy doors, to minimise sound transference, while ensuring pupils can navigate their way around while carrying a tuba.
It’s amazing to think that a building of some sort has been on this site since around 1421 and fascinating to think of the various uses to which it has been put. I feel very privileged to be involved in just a small part of the school’s latest evolution and hope that such a culturally important building is here in 600 years’ time for future generations. I also hope, from a regulatory sense, we’ve done it justice.
The project has been on site for the last 12 months, with an estimated completion date of February 2012. The second phase of the project will be the internal fitting out of the concert hall. Chetham’s is continuing its fundraising with its ‘Raise The Roof’ campaign.
Andy Foolkes is a Project Manager in the North West Office of Butler & Young
- All images by Daniel Hopkinson, reproduced by permission of Justin Risley, Stephenson Bell Architects
- For RICS members, related e-books include Understanding historic building conservation and Materials & skills for historic building conservation. Go to www.rics.org/ebooks to open, temporarily download or print sections
- BCIS Online can provide early cost advice for building schools. For a free demonstration visit www.bcis.co.uk/demo
- Related competencies include: T033, T013