National Gallery Lower Galleries by Wright & Wright

Architect Wright & Wright
Location Trafalgar Square, London
Completed 2010

When Wright & Wright was appointed to refurbish the National Gallery’s 515sq m lower galleries in 2009, they hadn’t been touched since the late 1970s. The rooms, next to the red-brick- coloured espresso bar that was part of Dixon Jones’ 2005 intervention, featured tired green carpet with a postmodern detail, orange textured fabric walls and clunky track spotlights. The spaces felt oppressive because the ceiling had been lowered to accommodate the services above and the galleries tended to be overlooked by visitors.

The brief for the refurbishment had recommended minimal intervention. James Taylor, a partner at Wright & Wright, says the client had just asked the firm “to leave the walls, tidy up the ceiling and install new lighting”, but like most astute architects the practice managed to achieve a bit more.

The £1.2 million project didn’t involve any major structural changes, apart from enlarging some of the doorways and adjusting the ductwork to gain more floor-to-ceiling height. Suspended ceilings of fibrous plaster casts and stretched membranes were used in each of the rooms to conceal ductwork and spotlights.

The floors were stripped and the screed replaced. This was then laid with 21mm engineered European oak boards, sanded and finished with a polyurethane lacquer for long-term protection.

Ceiling membranes

All five gallery ceilings feature French-manufactured Barrisol membranes that diffuse the new spotlights to replicate daylight. The membranes are stretched between fibrous plaster casts to create suspended ceilings that conceal ductwork.

The central octagonal gallery has a fibrous plaster dome and circular membrane, while the membranes in the surrounding galleries are rectangular.
The membranes were stretched and fitted into an aluminium frame that abuts a perimeter light track.

The architects wanted a very precise and sharp-edged finish for the fibrous plaster casts, which could only be achieved by making the moulds in a factory-controlled environment.

An 18mm plywood cantilever was fixed to the ceiling to which the plaster casts were screwed. Owing to its extra weight, the dome in the octagon room had to be held up with steel wires dressed over mild steel joists.

The joints were then filled with a very fine casting plaster and primed, and the casts then painted white.

The Barrisol membranes were levered into a groove within the aluminium frame, stretched across and tightened. Warm air was then applied, causing the material to expand. As it cooled it gradually contracted into place and tightened further. The material doesn’t sag over time and when the lights need to be changed the membrane can be removed and then replaced without reapplying warm air.

Diffusers at either end of the rectangular suspended ceilings extract hot air, and warmed or cooled air is supplied to the galleries via low-level wall grilles. Tracks inserted into the suspended ceilings enable spotlights to be moved to illuminate particular paintings.

Sliding doors

Sliding doors are used for the four exits from the central octagon gallery, allowing rooms to be closed to the public. These replace highly varnished mahogany folding doors. The sliding doors are made from laminated spruce clad in chipboard and lined in Yorkite paper and sprayed matt black.

To accommodate the new doors, the four openings had to be enlarged and some of the load-bearing masonry removed. The doors are 54mm thick, 4m tall with 960mm-wide leaves and are supported from the top.

The inner workings to the sliding mechanism — the running track, steelwork and nylon rollers — are concealed by a bespoke brass flap designed by the architect.

When the door slides open the flap at the head of the door drops down to hide the inner workings. When the door closes a triangular-shaped kink at the end of the flap catches and ensures the flap lifts up.

The door surrounds are lined in Indian black granite and supported on mild steel framing. A 40-tonne block of granite from India was cut in Carrara, Italy, and then shipped to England. It was also used for the 450mm-tall skirting and the 600mm-wide margins on the floor.

Client: The Trustees of the National Gallery
Architect: Wright & Wright Architects
Main contractor: Fairhurst Ward Abbotts
Services engineer: Hurley Palmer Flatt
Structural engineer: Hurley Palmer Flatt
Mechanical & electrical subcontractor: Capri Mechanical Services
Granite cladding: Stone Productions
Fibrous plaster ceilings: Profibre UK and N J Milroy
Stretched fabric manufacturer: Barrisol
Stretched fabric ceiling installer: P J C Acoustics
Brass edgings to doors: Random Products
Oak flooring: Floors Truly
Floor screed: Ardex