We prefer terms that say what they mean: low energy, built to last, built with less concrete, designed to capture the sun. Ecological design encourages decisions that will mitigate harm to the environment, and indicates a relationship between human occupation and the planet. Instead of seeing it as a constraint, we see it as an opportunity. We take these issues as an incentive to embrace the natural world and make buildings that celebrate life: the cycle of the seasons, the warmth of the sun, or the passage of time. For us, a good low energy heating and ventilation strategy and feeling cool on a hot day are two sides of the same coin.
How many times are our memories infused with the qualities of a particular place? If we conjure up places we know and have loved, what springs to mind? Often the qualities of a place are hard to describe, and yet assert a powerful presence. Talking about architecture is often difficult, as our emotional response to place is often not pinned down by describing what it looked like. I can conjure the feeling of a room in a house that begins with the feeling of the sun on my face on a winter’s day, and includes the lofty timber ceiling, with the faint smell of the wood. It ends with the sound of my parents’ friends talking into the night as I lay listening to their laughter, with the sweet smell of pipe tobacco rising up the stairs.
Each memory of a place we’ve loved- often from childhood or holidays- is affected by a sensory experience; the feel of the floor underfoot, the squeak of a gate when someone arrives, the warm sunlight on a cold afternoon.
The essential qualities of a place are determined as much by geology as people. Mole is based in East Anglia, where towns are made out of timber rather stone, as in the Cotswolds, or Sussex clay and brick. Lime-rendered oak frames give buildings and streets their own special character, with the largest ancient structures using timber inventively to span greater distances- the largest tithe barns using up to 400 trees. At Mole we have long seen timber as the perfect constructional material; low in embodied energy, easy to transport, forgiving to work with, and suited to quick and clean construction. We have worked with most forms of ‘modern methods of construction’ (MMC), from our first building using prefabricated panelised cassettes to recent buildings made from cross laminated timber (CLT) sheets. Timber absorbs CO2 during its growth, and as long as this is locked up in a building is of environmental benefit. The development of structural timber from using individual oak trees into engineered products has meant a great leap in what is possible; more or less anything that can be done in steel can be done in timber, and at a fraction of the cost to the planet. There’s a beauty in natural materials that is hard to replicate, and we love the fact that for all the technical advances in timber production, we still simply love the smell of cedar, the figured beauty of douglas fir, or the richness of a piece of cherry.
Passivhaus is the new buzzword when it comes to low energy, sustainable design. It’s a set of complex design rules that are designed using PHPP software to produce a building that uses minimal energy to keep it warm. Devised by building physicist Wolfgang Feist, the system reinforces many of the technical solutions that Mole has arrived at through empirical research. Essential aspects are that the building only requires minimal energy for heating/cooling (15kWhr/m2yr), and that air leakage is very low (0.6 air changes/hr at 50 Pa pressure). A passivhaus dwelling will always use the heat from solar gain, minimise windows to the north, use a mechanical ventilation system with heat recovery, and employ highly insulated windows and doors. The standard of construction is also measured, as the certified building is tested to ensure that the maximum air leakage is achieved. We have measured the energy use of a number of our houses, all of which achieve this stringent level of energy use, despite being designed before the Passivhaus system was ‘available’ throughout the UK Passivhaus Trust. Since then we have gone on to adopt the system; our first certified building was shortlisted in the UK Passivhaus Awards in 2014.