The ELC is part of the Hallam City Learning Centre, Sheffield. It is based in the grounds of Notre Dame High School.

The ELC was designed to provide an airy, flexible and enjoyable learning environment within a very energy efficient building constructed of sustainable materials. The building has a structural oak frame, combining this sustainable and very traditional building material with modern jointing details. Onto this are attached wall panels insulated with sheep’s wool and woodfibre boards rendered in environmentally-friendly non-cement lime render. The roof uses very similar insulating products and is tiled with traditional Cedar roof tiles. These are fire-proofed with products chosen for their ability not to leech out of the timber during rainfall and pollute the surroundings. A solar thermal water heater is installed on the roof and the building has been painted internally with a range of very low and non-VOC paints.

The building is naturally ventilated, through the use of remotely-controllable roof windows, and was designed to maximise the amount of natural light to provide a pleasant area to work. The large glass doors lead into the garden, an area which in the future we plan to develop into a wildlife garden and allotment area. Behind the garden is a concealed pathway leading into the woodlands and towards the pond.

The Construction Process

The Construction Process

The oak frame sits on steel piled foundations, allowing the building to sit comparatively lightly within its woodland environment. Once the oak frame was erected, timber panels were attached to the outside. Each panel comprised a sheet of OSB and a grid of timber studs. The space between the studs was filled with sheep’s wool and onto the studs was fixed a continuous outer layer of Pavatex Diffutherm woodfibre boards rendered with Baumit lime render.

Inside the classroom, rendered woodfibre boards infill the space between each exposed structural oak post and in the changing/wash room there are timber studs, sheep’s wool and plywood beneath the tiles between each post.

The roof has a similar woodfibre material beneath the shingles, albeit manufactured to be a bit denser (to give some extra strength to the roof). The woodfibre panels are made primarily out of waste material from sawmills. The space between the rafters, which form the roof’s structure, are filled with sheep’s wool insulation.

For pictures of the construction process click here.

About the Materials

Natural Building Technologies’ Pavatex Diffutherm (rendered wall) and Isolair (roof) woodfibre boards provide excellent thermal insulation. The product is carbon positive (locks up more than is used) and non toxic. It is relatively dense, giving a level of thermal mass usually absent from lightweight construction products. This limits summer overheating by delaying heat hitting the walls from the outside during the day from reaching the inside until night-time. Over 95% of the woodfibre boards are made from waste wood and from FSC Certified Sources. Waste material is recyclable, compostable and can be re-used for thermal energy production.

OBS (Oriented Strand Board) is an engineered wood product formed by layering and compressing recycled strands of wood and bonding them together with wax and resin adhesives. The fibre grown is from sustainable forests and tree farms, and is recyclable into other products.

Baumit lime render is mineral based and in conjunction with the woodfibre boards allows for a non-toxic, breathing wall system. Any moisture that gets into the wall (or roof) construction does not condense within the insulation but is instead expelled harmlessly to the external atmosphere. By comparison, vapour-closed constructions under such circumstances trap moisture within the building’s construction, leading to mould growth, a proven health hazard, and degradation of the building fabric.

Sheep’s wool insulation provides a safe and natural alternative to synthetic insulation. There are many benefits to using natural sheep’s wool, such as its ability to absorb moisture and still retain superior insulation properties. It has a naturally long lifespan and will extinguish itself in the event of a fire.

Thermal insulation prevents heat loss from the buildings by creating a barrier between the warm air inside and the cold outside and vice versa. The better the barrier the less energy is needed to heat or cool the building. The ELC has very high levels of thermal insulation, greatly exceeding current Building Control requirements and in places exceeding the extremely stringent thermal insulation requirements being considered for the 2016 edition of the Building Regulations Part L.

Burnell Briercliffe Architects: http://www.burnell-briercliffe.com/  

Natural Building Technologies: http://www.natural-building.co.uk/