Snickers Workwear Magazine 1
Women’s Special I Hanna Nilsson We’re in an old l
imestone house in the village of Kastlösa on the island of Öland, the second largest Swedish island, which is located in the Baltic Sea, just off the coast of Småland. In the attic, Hanna Nilsson is smacking clay onto a brick. This is going to be incorporated into a type of fireplace invented more than 30 years ago, but that never really took off. Hanna, what’s the deal with this oven you’re building? This is a type of oven that was invented in Finland in the 1990s. It’s made exclusively from natural materials – clay, brick and a little mineral wool. There’s probably no other fireplace that utilises the energy in the wood so efficiently. If it’s designed properly, it only needs wood to be added once or twice a day. The energy released during combustion is stored in the mass of the oven and chimney and is emitted over 24 hours in the form of radiant heat. It does sound a bit odd for a recently graduated architect to change career so drastically. What happened? I’ve always dreamt of being able to do my bit for a more sustainable construction sector, ideally in a profession somewhere on the boundary between art and construction. And building “Creating the perfect clay is a complex task. The colour and consistency are governed by the climate and clay type in the area. Clay can be anything from white and yellow to red, blue, grey, brown and black. It’s more or less plastic and more or less water-absorbent, and its fire resistance varies. This turns every new project into a challenge,” says Hanna. CLAY AS A CONSTRUCTION MATERIAL Clay is one of the oldest construction materials in the world. It’s been used throughout the ages, at the four corners of the globe, to build everything from cottages to castles and mansions. A significant proportion of the Earth’s population still lives in houses made from clay or soil in some way. Plastering walls with a claybased mortar to provide insulation against draughts has been traditional in the Nordic countries since the Viking age. The smooth clay surface provides a fine basis for distemper and a smooth surface for wallpapers. Clay mortar differs from other mortars such as lime or cement mortars in that it does not burn. So in other words, there are no chemical reactions during the drying time. This makes the clay water-soluble, but also very elastic. This makes it easy for it to follow movements that can occur at high temperatures in an oven. Clay can be mixed in advance and stored over a long period. 24 autumn/winter 2018 I Snickers Workwear