Design Architecture Crossway Zero Carbon Home Brings Back the Timbrel Vault By Lloyd Alter Design Editor University of Toronto Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. our editorial process Facebook Facebook Twitter Twitter Lloyd Alter Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Design Tiny Homes Architecture Interior Design Green Design Urban Design all crossway photos via architects website Architect Richard Hawkes is just finishing what he calls a zero-carbon house, using all of the latest technologies but also demonstrating "how contemporary design can celebrate local materials and crafts and integrate new technologies to produce a highly sustainable building that sits lightly on the Earth" The dramatic arched roof, in particular, is an ancient technique called timbrel vaulting, which we cover in greater detail below. The timbrel vault not only is incredibly thin and efficient, but gives the interior that lovely warm look of brick. Old timbrel photos via low-tech magazine According to Low-tech Magazine, The timbrel vault does not rely on gravity but on the adhesion of several layers of overlapping tiles which are woven together with fast-setting mortar. If just one layer of thin tiles was used, the structure would collapse, but adding two or three layers makes the resulting laminated shell almost as strong as reinforced concrete. The structural engineer, Dr. Michael Ramage, told Leo Hickman of the Guardian: "The vaulting gives the house plenty of structural strength but obviates the need for embodied-energy intensive materials such as reinforced concrete. It also provides it with great thermal mass, enabling the building to retain heat, absorb fluctuations in temperature and reducing the need for central heating or cooling systems." Hickman notes: It has often struck me when talking about how we might green up our housing stock just how often the solutions can be found by thumbing through the history books. Much of what is prescribed – insulation, insulation, and a bit more insulation – isn't exactly rocket science. Another demonstration of how to mix old and new technologies: a 3D printer study of the stair (also constructed on a Timbrel vault) and the finished stair. New Yorkers will recognize timbrels in the Oyster Bar in Grand Central Station; Bostonians can see them at the public library. But the master of the timbrel vault was Gaudi. It is a technique that uses very little material and a lot of labour, a combination that makes sense these days. Kris De Decker writes at Low Tech Magazine: Brick, stone and concrete are materials strong in compression (you can pile them up almost indefinitely), but weak in tension (if the structural breadth increases, the material has to be supported by many columns or it collapses). Nowadays, this problem is solved by steel structures or the use of steel reinforced concrete - the tensile strength of steel is significantly more than that of bricks, stone or plain concrete. Pre World War II, the weak tensile strength of brick was compensated for by superior craftsmanship. The "timbrel vault" allowed for structures that today no architect would dare to build without steel reinforcements. The technique was cheap, fast, ecological and durable. Richard Hawkes has shown that they still have a role to play; let's hope we see more of this.