Last week some of us got away from our desks and went for bike ride with some good friends at Native Architects, something we’ve not done for a couple of years, so it was good to get out and meet people again. For some in our team it was the first time meeting our more recent recruits in person! It was great to spend time pootling the lanes between their offices and Tadcaster, where we stopped for some lunch and a dip in the River Wharfe. We have worked with Chris and Sally and their team at Native for many years, and we share a passion for award-winning architecture and sustainability.
As well as having an eye for design, Native are particularly experienced with natural building materials and historic buildings. We have worked together on a number of completed projects including William’s Den and Husthwaite Village Hall, as well as current projects with Yorspace and at Whitby Distillery.
William’s Den makes extensive use of wood fibre and lime renders, as well as Hempcrete. These materials have lower embodied carbon than alternatives such as polyurethane, mineral fibre, concrete and gypsum plasters. But just as importantly, these materials are better for existing buildings and healthier for the occupants. Natural and traditional building materials are often vapour permeable and hygroscopic (often referred to as breathable – like Goretex), which means they let moisture through and absorb it, which is the total opposite to the often seen methods that rely on polyurethane and foil backed plasterboard with vapour barriers, seen on many renovation and new build projects. These critical properties of materials help to regulate internal moisture (humidity) for occupants, and also regulate the moisture levels in the walls that can otherwise lead to condensation, mould and rot.
The predominant construction and materials approach prevents condensation occurring in the wrong place and tries to manage moisture movement with barriers and weep holes. However if the systems are not used perfectly, or in the right order, then problems occur which can be difficult to resolve. For renovation projects this is harder, as not all parts of the system are always possible to install and exact build ups not easy to determine. The simplicity of traditional and natural materials is therefore appealing, although rendering in lime plaster will take longer, require skill, and extra drying time when compared with dry lining using PUR/PIR insulated plasterboard. However, the risks are more easily managed and the construction much more forgiving of variations and even mistakes. Other advantages include airtightness, as the systems usually involve wet trades that can better seal gaps in the external fabric, and also the decrement factor is increased, meaning that the building responds less quickly to external temperatures changes providing a greater degree of internal comfort and potentially lower energy use for the same U value. The moisture in the materials will evaporate during hot weather, giving an additional cooling effect. Very useful in the hot weather we have had recently… not quite as effective as a dip in the Wharfe though!