Timber frame specialist, Cygnum, has commenced delivery of a £5.1 million school building – designed and built to the ultra-low energy principles of Passivhaus construction. The new Oak Meadow Primary School building is part of Wolverhampton City Council’s £16.6 million Primary Capital Programme, set to transform the region’s educational facilities for primary age pupils.
Passivhaus buildings are designed and constructed to provide exceptional occupant comfort whilst using up to 90% less energy for heating and cooling than standard buildings. As a result, the completed structure requires minimal traditional heating and no air conditioning cooling systems, retaining existing heat gains in winter by using mechanical ventilation with heat recovery.
Designed by Architype Architects, the building at Oak Meadow Primary School
is a new two-storey, 2,500m2 structure being delivered by contractor Thomas Vale Construction. As a crucial element in the construction process and to achieve the required levels of insulation and air tightness for Passivhaus certification, a timber frame structure proved the perfect solution. Produced in the controlled environment of Cygnum
’s state-of-the-art manufacturing facility, the structural panels and vital components could be delivered to the finest tolerances.
The timber frame structure comprises a 340mm external wall insulation zone with a main air tight layer of 18mm OSB (oriented strand board), to the inner face of the external walls and first floor ceiling. OSB is water resistant and formaldehyde free and made of narrow strands of fibre cross-oriented in layers with a resin binder, it provides no internal gaps or voids for increased strength.
In Passivhaus construction, all components in the exterior shell are insulated to achieve a U-value that does not exceed 0.15 W/m2/K. For this, Architype specified cellulose insulation – to be installed on-site – for both the 340mm external wall and 400mm roof insulation. Made from 100% recycled newspaper and with zero ozone depletion potential, cellulose insulation has a thermal conductivity of 0.035 W/mK and exceeds BREEAM’s Green Guide rating of ‘A’, helping the building to achieve Passivhaus Standards.
’s innovative design incorporates the use of exposed glulam beams and posts in the main hall. The beams supporting the roof will be 200mm x 1000mm deep and span 11m, sitting on glulam posts of more than 6m high for an impressive aesthetic.
The new Oak Meadow Primary School building is being constructed next to the existing school, which upon completion will be demolished to make way for new playing fields. Once the project is complete, with an expected handover in April 2011, the school will officially open its doors to students for the new school year in the autumn.