Grass-roofed extension to conference venue wins Godalming Trust award

Citation

(2001), "Grass-roofed extension to conference venue wins Godalming Trust award", Facilities, Vol. 19 No. 5/6. https://doi.org/10.1108/f.2001.06919eaf.004

Grass-roofed extension to conference venue wins Godalming Trust award

Grass-roofed extension to conference venue wins Godalming Trust awardKeywords: Awards, Architecture, Building services

Carving out a building underground, and using waterproof concrete for its retaining wall sounds expensive. But architect John Onken's design and management of the extension to the headquarters of Quest Worldwide has proved that ecologically sensitive developments do not have to be costly in terms of resources or of time.

John Onken's extension to the Manor House, an imposing Victorian building set high on Farncombe Hill, near Godalming, has won the Godalming Trust Civic Awards 2000 category of extension to an existing building.

The Manor House, which overlooks protected woodlands, is the headquarters of international management consultancy Quest Worldwide, and a leading conference venue for managers in major companies. Quest needed to provide 18 new bedrooms plus a conservatory, gym and saunas.

The extension had to have minimum impact on the sensitive national environment and acknowledge the historic original building, formerly home to a master at Charterhouse School and war hospital.

Connected to the woodland

Quest commissioned John Onken, an architect based in Wimbledon, to design and manage the project after several draft schemes had been discouraged by the local planning authority. John proposed that the new accommodation should be built into the hillside at a subterranean level, fronting the Manor House. Each bedroom has a large window wall which provides each guest with their own view over the surrounding woodland and of its wildlife.

"The positioning of the extension created an opportunity to break with the traditional design of the Manor House, but in a sympathetic manner", comments John.

The new "green" roof became a lawn and garden for the use of conference delegates in front of the Manor House's existing meeting rooms.

One worry was that accommodating guests at below ground level could be perceived as "sending them to the cellar". By designing the building as spacious and light, definitely not damp, and connected to the woodlands outside, the extension became an integral part of the conference venue.

The inherently high cost and complexity of carving out a building underground was kept within budget and to time by the close co-operation between John Onken and the contractor, Bowmer and Kirkland Building Services of Derby. This strong team proved critical in saving money and time for their client. Quest had conference bookings well in advance of the project, so downtime had to be kept to a minimum.

For the rear retaining wall below the lawn, waterproof concrete was used instead of traditional tanking methods in the retaining wall waterproof concrete. Caltite seemed an expensive alternative to the standard concrete. But by investing in this technology the entire operation waterproofing in situ concrete was cut short. Two weeks were therefore cut from the notorious "groundworks" phase.

As with any building underground, the waterproofing can make or break the project. This project's green roof feature was built as a sloping concrete roof deck with a topping of polymer-modified asphalt, chosen for its high elasticity and long life. The "sandwich" of insulation, drainage layers, topsoil and turf was then added while work carried on below undisturbed.

Amanda Cartridge, Director of the Manor House comments: "John worked closely with us from the beginning to make sure that disruption was kept to a minimum. The new extension has fundamentally changed the way that we host our clients.

"Since the extension opened a year ago, at least 15,000 clients have visited the Manor House and walked in our landscaped gardens, I would say that the majority of them did not notice the bedrooms underneath the gardens, which is a feat in itself.

"Everyone who uses the bedrooms enjoys them. Our housekeeping staff like them; and at the moment the clients can sit at their desks and look out of the big windows over the autumn woodlands. The Surrey countryside seems to surround them as they work."

Further information is available from Jenny Peterson, RIBA South East Region. Tel: +44 (0) 1892 515878. Or contact John Onken, John Onken Architecture. Tel: +44 (0) 208 946 1382.