«SVITLO» - a house for the future. The interiors of this concept for a catalogue house are characterised by extensive use of wood combined with accents of clay. Together with interior plants and the greenhouse addition, the rooms become in themselves an allusion to the forests that they came from.
Wood is used for all surfaces on the inside with various treatments. Ceilings are finished with untreated wood slats, and pine wood panels on vertical walls are tinted white with lime wash. Floors are covered with oak parquet. One of the characteristic features of the house is the double-height space above the living room, which is created with an exposed gluelam wood structure. The columns are also visible where they continue up to the ridge beam. Clay walls consist of a layer of finished clay plaster on the inside of a Lemix clay panel (alternatively a Schleusner hemp light clay plate). The clay is allowed to dry such that it presents a rough, organic texture that becomes in itself an interesting element in a room.
The living room, kitchen and dining area are combined in a large common room on the ground floor with with varied ceiling heights. The kitchen cabinets and island are placed under a lower part of the ceiling and offer a sheltered space that looks out onto a sofa group and built-in bookshelf. This room also has direct contact with the open stair and an internal balcony on the second floor, where there can also be found two more bedrooms, a bathroom and a flexible room. The main bedroom lies on the other side of a sliding door behind the bookshelf, where it also has its own bathroom and washing room. Sleek lines of modern furniture offer an interesting contrast to the roughness, simplicity and distinctiveness of the wood and clay surfaces. The cloud lamps shown in these illustrations are by Studio Makhno.
All interior surface treatments are open to the diffusion of water vapour in support of one of the house’s key ecological concepts: so-called «breathing walls». A traditional passive house is constructed with an air-tight vapour barrier on the warm side (normally plastic-based foil), and excess moisture that accumulates inside is ventilated out of the house through a mechanical ventilation system. While this concept can lead to a significantly high level of energy-efficiency with impressive air-tightness and corresponding low heat losses through infiltration, it has several notable disadvantages. First there are all of the problems that one runs into with mechanical ventilation, including reduced interior area (mechanical ducts take up a lot of space), dependence on electricity for the house to function, and the environmental impact of all of the complex materials that are required to produce and maintain ventilation systems (especially important is the need to maintain and replace filters, which a lot of people do not properly do). In practice, living in such a house is like living in a plastic bag that is made inhabitable by an attached machine. The vapour barrier must be carefully installed to avoid any perforations, because in a vapour impermeable construction any water vapour that escapes through even a small hole can become trapped inside and lead to condensation problems later. In practice this level of accuracy can be difficult to achieve.
The concept house «SVITLO» is based upon user-controlled natural ventilation with vapour permeable external constructions. This means that there is no impermeable vapour barrier in the walls and roof, but rather a permeable vapour «brake» (Nor. dampbrems) which is there to maintain a beneficial pressure differential between the interior and the exterior but does not hinder vapour diffusion completely. Such a concept is durable in the sense that it allows water vapour that might permeate the external structure to diffuse out, and a plastic vapour barrier can be replaced with a paper-based product (alternatively a so-called «smart» material with a variable vapour diffusion). Natural ventilation also makes full use of the hygroscopic nature of untreated wood and clay, which together with wood-fibre insulation in the walls/roof and the vapour brake absorb and store excess moisture which then can be released into the air again when the ambient levels sink. In such a way the materials that the house is made of act themselves as a passive buffer against a poor inner climate, and they have even been shown to reduce the overall need for ventilation in some studies.
The house is otherwise heated primarily with passive solar energy. The plan solution is optimised to exploit sunlight, and the large south-facing window surfaces facilitate direct illumination of much of the interior environment. Heat can also be temporarily stored in the greenhouse. When heating is necessary, the house is heated with water-borne radiant heating installed in the floors with a low transmission temperature. The energy source can be geothermal, an air-to-water heat pump or an efficient wood-burning pellets oven, depending on the context that the house is built in. The plan organisation also facilitates the passive dispersal of radiant heat.
The characteristics and trade-offs between various energy efficiency concepts for ecological houses represent a massive topic which I intend to write more about in coming posts.
***