Specification focus: Drywall: Seeing is believing

Drywall systems are now an integral part of most modern buildings, and at the Manchester Civil Justice Centre traditional gypsum products have been blended with steel and glass to bring a fascinating building design to life.

T his is one of the largest and most challenging drylining contracts we have ever undertaken, in fact I've not seen a project of this complexity before," says Gavin Colclough, operations director of Horbury Building Systems, the drywall contractor appointed by Bovis Lend Lease, the main contractor on the Manchester Civil Justice Centre.

The £113m building was opened officially in October 2007 and serves as the headquarters of the Department for Constitutional Affairs in the north west, consolidating all its office and court functions in the region. The Civil Justice Centre is unlike any other building in the city and is said to be the largest court project of its type since the Royal Courts of Justice were built in The Strand, London, in 1870.

The cubic-styled 16-storey building provides 27,870m² of accommodation, consisting of 47 court rooms, four tribunal courts and 75 consulting rooms. The extent of the drylining and partitions throughout the building was considerable and an intrinsic part of the design concept.

Horbury began work on the £14m contract in May 2005 and had in excess of 150 men install more than 250,000m² of plasterboard and 500,000m of metal. Roughly 10,000m² of wall linings, 41,000m² of drylined partitions and 12,000m of deflection head were also necessary.

Sustainability issues

Sustainability and environmental impact over the life of the project were prominent issues and Horbury's drylining was key to the implementation of natural daylight and ventilation throughout the building.

Suspended within the ceiling void, Horbury constructed the light air duct, a system never used before in the UK, and used only once before worldwide, in Australia.

Colclough continues: "This project is a prime example of a successful partnership between a specialist drylining company, the main contractor and the design team. All too often we get forgotten about and have to play catch-up, but Bovis Lend Lease, the main contractor, gave us an opportunity to contribute perhaps more than we would normally do.

"Perhaps the sheer scale of the contract made more of an impact, but we were able to debate the design, how we co-ordinated with other trades and the sequencing of our work.

"Attention to detail and effective co-ordination was very important. Take the light air duct. It was a massive 7m-wide fire rated, load bearing, airtight and light reflective structure that was entirely constructed on site. No mean feat I can assure you.

"The high performance ducts carry natural light and air into the building. A high degree of workmanship was required to limit the air loss. And as this was a new concept, the manner in which our supervisors briefed our installation teams effectively was critical. We set up a series of tool-box talks that focused on working with the different materials, such as glass, and we had to strengthen our inspection regime.

"What was good was that we were able to get involved in reviewing the design concept. We took on responsibility for the structural design of the LAD frame and proposed some programming changes to help make the installation process more efficient."

The wind scoops were constructed at the north and south ends of each floor, facing the direction of the wind the outside air enters at the sides of the atrium and travels along its airtight structure entering the public areas through air slots within the partition and ceilings. Attention to detail was therefore critical.

The eastern façade of the building not only establishes the building as a court, but provides an environmental curtain that maximises natural daylight, while controlling solar gain.

The natural daylight enters the light air duct through its glass sides and, due to the high reflectivity of the inner surfaces, the light is transmitted along the length of the building with the duct. Further glass panels incorporated within the heads of the partitions allow the light to diffuse throughout the public spaces of the building.

A further design development challenge was the requirement for the partition heads to be made from glass. The partition walls were effectively free-standing, as they could not take any support from the glass, but also the deflection, fire rating, acoustic performance and air-tightness of the partitions had to be maintained at this intersection.

Gavin describes how they came up with a solution: "Structural performance of the partitions was achieved by incorporating structural steel posts within the width of the partition, which were spanned by lintel sections formed by boxing together traditional lightweight stud and channel sections.

"Further steelwork was incorporated within the partitions to support the large judges' bookcases, which are held off the partitions and above the floor," he added.

And why was this project so challenging? Gavin concludes: "There were large open spaces with smooth sharp lines. Instead of incorporating traditional architraves and skirting boards, the design here uses flush-fitting doors and recessed vinyl skirts, all of which are formed against recessed trims. We installed these with a tolerance of 2mm specified for certain finishes."