Dirt, weathering, rainwater. These are the three most common problems that arise in building conservation, so to work with the legacy of an architect who recognised the threat of these elements as a key part of his design practice was particularly fascinating.
Denys Lasdun was ‘one of the first British architects to recognise the role of dirt-laden rainwater’ in the design and longevity of British buildings and sought to reduce damage from these sources through clever drainage systems hidden throughout his facades.
Such systems were most effectively utilised in Lasdun’s ‘strata’ design for the National Theatre in London, comprising a ‘horizontal ‘stacking’ of accommodation and activity levels’, and finished in 1976.There was no public commission nor competition for the design of the National Theatre. Rather, Lasdun began a long process of collaboration with his partner Peter Softley in 1964, working with the National Theatre Committee – chaired at the time by Laurence Olivier – to understand their needs and desires for the building. Given the nature of our project, which was to carry out a trial restoration in the foyer and restaurant of the space, it was interesting to find that despite usually beginning his plans for the exteriors of buildings, Lasdun and his collaborators were intent on working from the inside - out. He recalled this process - ‘we reacted as architects with spatial responses’. In this he recognised the importance of spatial planning for different genres of theatre – ‘the open situation which the Greeks and Elizabethans knew, and the confrontation situation which is realist theatre with a proscenium, which everyone has been writing for during the last 300 years.’
While Lasdun catered for all types of theatre, designing a series of auditoriums, his most emphasised type was ‘the fourth theatre’. This was a gestalt approach to the architecture of the National Theatre which saw the entire contents of it – the auditoriums, the restaurants, the social gathering spaces, kitchens, toilets, balconies, gardens bars, staff rooms, lecture rooms, function rooms – as one coherent, communicating space. This was achieved not only in the ‘strata’ facade but the approach to thoroughfares and walkways within – ‘streets, squares, gardens, cul-de-sacs, where I hope life – just as it crosses Waterloo Bridge – will cross the building’.
To conservators, these design plans aid understanding of the kinds of wear and tear the building would have undergone through the years as a public space intended for bringing the outside landscape into the theatrical space. Yet more intriguing for us was the way in which Lasdun went about this concept of interiority – through his use of materials.
Lasdun decided to match the colour of Waterloo Bridge to the Theatre’s exterior by adding whitening to the concrete used to construct the building. He intended the building itself to ‘weather like stone…it is a permanent building which will take on the marks of time and look better for that’. Here, Lasdun touched on a common conservation conundrum — to clean or not to clean.
From a conservation perspective, it is important to propose a treatment scheme that is in-line with the client’s request, which usually involves the object looking like new. But the extent to which restoration is carried out, and the approach taken, is the next obstacle. The holistic, community-led approach that Denys Lasdun prioritised for the Theatre meant that the building should reflect its urbanity and be bedded into the city. It was never intended to be a ‘temple of culture’, but instead ‘an extension of the lifeblood of the city…[drawing] its strength from Waterloo Bridge… the decorations will be people, carpet, concrete and light, with views of the Thames and London beyond.’. The lack of emphasis on structural supremacy and material/decorative domination informed our own approach to the public spaces we tackled, which were primarily in the restaurant and foyer.
The concrete cladding that covers the interior and exterior of the Theatre is textured with ‘board-marks’, created by imprinting planks of wood into the drying concrete as long planks, creating a woodgrain texture on the surface. As the interior schemes of the restaurant developed and changed over time, losses to this façade were inevitable – holes and damage from the installation and removal of various fixings, modernising lighting systems, decorative fixings and structural reinforcements all altered the original wall profile. As well as losses identified in the wall profile, numerous accretions were found. Black and white paint accretions and adhesive residue were found at the entrance to the area. Pencil scribbles and markings were found on the walls and ceilings.
Previous conservation attempts to fill these losses and match the original scheme had, for the most part, failed and discoloured. The result was a jarring contrast between the historic scheme and later fills where a satisfactory colour match had not been achieved. Although it was possible to mask some of this disparity using raking light, it was decided that these failed historic fills were tackled alongside the new losses to the concrete scheme.
As is typical in historic interiors conservation, the priority was to seamlessly integrate modern fills into the original wood-grain composition. This proved quite tricky in the context of the building, as unlike in more complex decorative schemes, Brutalism is characterised by ‘its apparent lack of decoration and detail…an austere, minimalist aesthetic’ that does not draw the eye to any particular detail or design quirk. Camouflaging the new fills was therefore the priority.
In establishing a treatment plan, we first tested the wall materials to find a suitable fill material. It was decided that the reversible conservation grade resin Paraloid B72 would be bulked with a combination of calcium carbonate (an inert filler), sand, and pigments. This material is pliable, so it could be textured using surface tools to match the surrounding wood grained concrete. It was a practical solution in that Paraloid B72 does not yellow under exposure to UV light and can be easily removed using Acetone.
Once the fill material was established, the next step was testing to find a conservation paint system that would match the requirements of the base and the wall. We needed a system that could be applied over both the new fill material and the extant mismatched historic fills to develop a coherent colour and tone scheme across the entire wall area. We chose paints with a low molecular weight, made up of aldehyde resin and solubilised with isopropanol, to increase the potential of matching the matte finish to the wall itself. Using these combined materials, which are stable and lightfast – resistant to light and sunlight – ensures there will be no change in colour or sheen over time.
The actual restoration process was a great experience. As can only be expected with the National Theatre, we worked amidst a hubbub of theatregoers, walkers, tourists, families, and other construction and conservation workers onsite. Although this project required minimal intervention, it was really satisfying to be able to restore the Brutalist spirit of the interior, and in doing so consider the edifying social politics of Lasdun’s architectural scheme.
