The Laboratory of Molecular Biology in Cambridge had nowhere for its Nobel Prize-winning scientists to present their research. So architect Feilden + Mawson and quantity surveyor Keegans created an auditorium extension on stilts – and here they reveal the details of how it was done

<B><font size=”+2”>Client’s brief</font></b> The Medical Research Council’s Laboratory of Molecular Biology, established in 1947, has played a leading role in a prolific half-century of discoveries in molecular biology, with 12 of its staff winning Nobel Prizes.
The Laboratory of Molecular Biology building on the Addenbrooke’s Hospital site in Cambridge was first occupied with 100 staff in 1962; since then its occupants have increased to 400 scientists, post-doctoral fellows, research students and support staff. The building’s original seminar room was absorbed into laboratory space, leaving nowhere to stage the research presentations that have always been among the institution’s most exciting events.
In 1999, the Laboratory of Molecular Biology decided to create a new lecture theatre attached to its main building, named after its founding director, Max Perutz. The brief was for a 188-seat auditorium for internal seminars and lectures, along with an exhibition and gathering space. The idea was that these facilities should be directly accessible from the existing laboratory and by external visitors, especially the disabled.
Backed by the Addenbrookes NHS Trust, which owns the whole site, and Cambridge council planning department, the Laboratory of Molecular Biology wanted its extension to reflect the prestige of the institution and to enhance the architectural quality of its existing buildings. The client also wanted a low-energy building that would accord with Medical Research Council policy and would not place significant additional load on the energy supply in this area, which was already operating at the limits of the available supplies.
The Medical Research Council sought design ideas from three practices before appointing Feilden + Mawson.
<B><font size=”+2”>Architectural design features</font></b>Feilden + Mawson agreed with the client that the only suitable site for the extension was a courtyard on the eastern side of the existing laboratory building. Although it was neatly enclosed by buildings on three sides, the courtyard came with two tricky problems. First, the site covered two large underground water tanks that supplied the laboratory building. Second, it conflicted with the existing main entrance on the lower ground floor on the same side.
The architect placed the new lecture theatre level with the upper ground floor, parallel to the existing main laboratory block and connected to it by a link wing at right angles. The client was concerned that the entrance to the building should be a significant one. Feilden + Mawson’s solution was to provide a main entrance, with lobby and reception desk, in the link wing, where it would give direct access to the auditorium and the existing laboratories on either side.
What is more, by placing the auditorium at upper ground-floor level, sheltered space was available underneath for bicycle parking; two electron microscopes, along with their related environmental control equipment, could be tucked beneath the reception wing.
David Julian, the MRC’s estates project manager, regards the impressive entrance and sheltered bicycle parking as bonuses that have exceeded his expectations.
The foundations were severely constrained by underground water tanks. However, the design team turned this structural adversity to architectural advantage by supporting the raised lecture theatre on two dramatically raking legs. The legs were carefully positioned so that their foundations fitted into the available space between water tanks and avoided increasing the pressure on them.
The entrance is reached from the pavement by a sweeping external staircase. Housed beneath the staircase are the access to the water tanks and a plant room serving the electron microscopes.
An auditorium foyer alongside the entrance lobby serves as an exhibition space, and a crush bar for use before and after lectures. Disabled car parking bays are located below the auditorium foyer, giving direct access to it by lift.
The auditorium contains 188 tiered seats including wheelchair spaces, arranged in a central bank served by two gangways, beside which are a row of single seats for latecomers or early leavers. A note shelf and computer link is provided for each of the seats in the main area. The lecture area is provided with a three-position lectern, which controls all the audio-visual equipment housed in a rear control room.
During building works, a temporary entrance was needed to allow the existing laboratory building to continue functioning. This was provided in the form of a new extension on the upper ground floor on the south side of the building. On completion of the works, this space was converted into office accommodation.
<B><font size=”+2”>Fabric, structure and services</font></b>The exterior of the new wing was designed to complement the two neighbouring laboratory buildings designed by Feilden + Mawson – the Wellcome Trust/MRC Building and the Hutchinson/MRC Research Centre. Metal rain-screen cladding was shaped to the curvilinear form of the lecture theatre, and curtain wall facades were used for the entrance and foyer.
The curved-metal, raised-seam roof is supported by a structure of reinforced concrete columns, beams and soffits, with the raised tiers of the auditorium formed by precast concrete floor slabs. This arrangement created ventilation plenums in the voids and allowed excess heat to be absorbed by the concrete structure. The walls of the lecture theatre are made of solid blockwork, with concrete columns carrying the steel roof structure. An external render coat was applied over the blockwork to seal any minor voids, then faced with insulation and the rain-screen cladding.
The soffit of the lecture theatre is also finished with insulation and render, and the roof is built up in soundproof layers of decking insulation and a welded membrane roofing layer.
The environment of the lecture theatre is controlled by a low-energy passive system. This provides a gentle movement of air at the correct temperature that enters the auditorium through the cooling void in the structure and the slots at each seating tier. After being extracted at high level, the return air is utilised to heat the foyer by means of a heat exchanger.
<B><font size=”+2”>Procurement</font></b>The Medical Research Council was keen to obtain best value from the selected contractor rather than merely work with the lowest tenderer. The reasons for this decision were twofold.
First, the council had adopted a general policy of moving away from traditional “first past the post” procurement towards setting up framework and partnering agreements. Second, a co-operative approach was required from contractors owing to the congested nature of the site and the close interface between the construction of the new lecture theatre and the Medical Research Council’s existing research and construction activities on the site.
Quantity surveyor Keegans, with the Medical Research Council’s estates management section, devised a best-value performance matrix that took into account, in addition to tender price and programme considerations, contractors’ site management proposals, their health and safety policies and records, together with their specific proposals for the project. Also considered were their performances on similar projects. These factors were weighted to reflect their importance to the client.
Tenders along with written best-value submissions were initially invited from seven contractors based on bills of quantities. Four of these contractors submitted tenders within Keegans’ scheme design estimate. The written submissions of these four were circulated to the client and design team for evaluation, and their bills of quantities were checked for errors.
These four contractors were then interviewed by a panel comprising representatives from the Medical Research Council’s estates management section, the users of the building, the architect, the quantity surveyor and the planning supervisor. After this process was completed, the four contractors were marked using the best-value performance matrix, and on the basis of this evaluation Haymills Contractors was appointed.
Haymills submitted the third lowest tender price.
<B><font size=”+2”>Cost control</font></b>The form of contract used was GC/Works/1/1998 With Quantities. This form of contract places emphasis on the contemporaneous or prior agreement of the costs of variations, and tight cost control was maintained throughout.
During the contract, the client added two further elements to the project – the installation of a fume cupboard stack and the refurbishment of an existing laboratory. The value of both these items of work together with their programme implications were agreed by Keegans and Haymills prior to client authorisation, and both were successfully incorporated within the contract works. Because neither of these items physically form part of the lecture theatre extension, they have both been excluded from the following cost plan.

Vital statistics

Lecture theatre extension to the Laboratory of Molecular Biology

Addenbrookes Hospital, Cambridge

Eastern Region RIBA Spirit of Ingenuity award 2002

Low-energy design features
Displacement ventilation through a plenum and infiltration system

Architectural design features

  • Dramatic sculptural form generated by the function of the building and site constraints
  • New entrance adds visible focus and identity to the whole laboratory complex

    Cost features

  • £1,597,525 for 558 m2 gross internal floor area.
  • Unit construction cost £2863/m2.
  • Cost per seat £8589

    Construction period
    101 weeks

    Procurement features

  • Contractors’ tenders assessed according to a best practice performance matrix: the third lowest tenderer was appointed
  • GC/Works/1/1998 With Quantities contract enabled tight cost control