Peter Rich investigates masonry vault structures for the Prince of Wales’ sustainability garden party. Photography by Michael Ramage
Where we are different,’ explains South African architect Peter Rich, ‘is that we’re actively trying to create the weakest tile possible, not the strongest.’ He’s describing the processes involved in the creation of his latest masonry vault structure, the Earth Pavilion, designed with engineer Michael Ramage and recently built in the grounds of London government mansion Lancaster House.
Conveniently coinciding with his opening lecture as part of this year’s Royal Academy Autumn Architecture Programme, Rich was invited by the Prince of Wales to deliver this full-size mock-up after the prince saw the 2009 World Architecture Festival (WAF) Building of the Year, Mapungubwe Interpretation Centre (AR February 2010), and wanted to see this technology enacted as part of his sustainability initiative Start Festival, for which Lancaster House is one of the venues. Since winning WAF Mapungubwe has been widely published, bringing a hitherto unknown building comprising three different types of handmade earth cement vaults to world attention.
Yet despite this, the challenge that remains frustratingly out of the architect’s reach is how to attain similar recognition in Africa, where such technology has a more important contribution to make. As Rich explains, all too often people overlook this method of construction, seeing it as too indigenous to be progressive.
The architect’s particular focus is Rwanda, where he says traditional thatched huts are being replaced by inefficient and inappropriate steel structures, imported in the name of progress. Recalling a similar condition to one previously described by the AR in Malawi (AR June 2003), what is desperately needed is a form of construction that does not rely on foreign materials. Mapungubwe exemplified this ambition - using local materials shaped by local hands - and the earth pavilion was intended to explore those possibilities in London. Unfortunately, however, the architect was not permitted to dig up the nearby Royal Park, so the main contractor John Perkins jumped on his motorbike and headed to Barking, east London, where he found an ample supply of clay-rich mud.
Built in 14 days, with only a few weeks’ lead-in, the whole process relied on every contributor sharing this can-do spirit, a spirit that project architect Tim Hall likens more closely to that of adventure sport than construction management. ‘We designed it over a three-day period,’ Hall recalls, ‘while Michael was in Mexico and Peter and I were in South Africa.’ Then came the less predictable process of construction, when each day a new challenge placed the feasibility of the project in jeopardy.
Soon, it became clear the client’s project manager had to go. ‘He wanted to begin by doing a full cost appraisal,’ says Rich, ‘but we simply didn’t have time. We said to him: “Step aside and we’ll make it happen”.’ So Hall, who had previously worked in the UK, called on his old friends for recommendations and before long the team was assembled, including set designer Scena Productions to build the plywood formwork, and stone mason Sarah Pennal, who pulled out of another job to construct the vaults using the hand-pressed mud tiles.
The tiles are of course the key component, assembled here in a two-layer 40mm thick sandwich. Made with as little cement as possible, and hence being as weak as possible, the composite arrangement of the tiles required detailed structural modelling by Ramage in order to predict the form’s composite strength, reinforced in this instance with a light gauge interstitial geotextile membrane.
It’s this sort of technical innovation that Ramage and Rich intend to pursue further, forming a joint venture which will look into options such as a composite cavity that will significantly improve thermal mass. On this occasion, however, one of the more surprising outcomes of this project relates to taste and aesthetic, as Pennal brought a level of finesse to the process that was previously less important to Rich. ‘She was so English about it. So refined. And in the end I asked if we could tell the story of the process by exposing a range of finishes from rough to refined,’ he says.
Recognising that such refinement could help overcome the stigma that this form of architecture is too indigenous, Rich acknowledges the need to appeal to the vanity of the rich first, describing some potential luxury housing jobs in which he hopes to be able to use this technology. ‘Once we’ve shown how it can satisfy an aspirational market, it will hopefully feed down more directly to influence the architecture of the villages.’ If this strategy works, Rich will then be able to roll out this technique in collaboration with the sorts of communities he is committed to serving which, in his own words, will be ‘so much more rewarding that dealing with some plutocrat and their bloody bathroom tiles’.