Ian McKay Dip Arch RIBA
Do you find yourself wondering how you are going to afford to keep your home warm in the years to come? Are you thinking about moving or investigating an energy efficiency refurbishment? It begs the question, how much existing building stock is suitable for our energy and resource starved future? That question is particularly relevant with the arrival of the Government’s Green Deal programme and for a town like Lewes where so much of the building stock is old, solid brick or stone constructed and characterised by small windows that afford little useful solar heat gain.
As an architect working on low carbon new build and refurbishment projects for some twenty years, I have grown increasingly convinced that to make super efficient and healthy buildings, that will save us from unaffordable heating bills in the future, we are better off either with a rebuild or a radical over cladding of the original. This will challenge our preconceptions of what our homes and our cherished townscape should look like. The alternative is that our historically important areas will be inhabited by those who are hardy enough to get through cold winters with minimal heating and those who can afford exorbitant heating bills.
Many people think that old buildings can be made more thermally efficient by insulating them from the inside. Apart from Lewes’ fine collection of old timber framed and mathematically tiled buildings where this can be done relatively easily and safely, internal treatment onto old masonry walls is a risky course of action. Once insulation is installed, the old wall is going to stay colder and wetter for longer with increased incidence of frost damage to brick and lime-based mortars and renders. Any timber floor joists and lintels embedded in the wall are likewise going to decay quicker – not great when you are trying to conserve a building. Secondly, that transition between warm insulation and cold wet wall is perfect for mould growth and creating unhealthy internal environments. As well as changing the building physiology, we must remember that much of Lewes’ housing stock is already spatially challenged and many will find it unbearable to lose floor space to a layer of insulation. Put an external insulation ‘jacket’ on the old building, on the other hand will create a more thermally efficient, healthier and longer lasting building.
It is important that we conserve fine examples of traditional building techniques but I can see increasing degrees of conflict between how we value our built heritage and the need for ‘affordable warmth’. I used to live near Lauderdale House in north London which was a tudor house on the inside but looked like a Palladian villa on the outside – the Georgians did a number on it for stylistic reasons and very probably to improve its weather tightness. I think there is a lesson there about not being too transfixed about preserving what buildings look like and instead adapting buildings so they meet our current and future needs.
September Edition 2013