Schöck Isokorb for Passivhaus Large Project of the Year
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Winner of the Large Projects category of the UK Passivhaus Awards 2021, Agar Grove, in Camden, is designed to tackle occupant wellbeing, climate action pledges and fuel poverty. The avoidance of thermal bridging is therefore a key element in the design detailing and to ensure optimum performance, the balconies and parapets incorporate Schöck Isokorb technology.
Claimed to be the largest Passivhaus development in the UK and certainly Camden Council’s largest community investment project, Agar Grove, in North West London, is undergoing a six-phase major regeneration. It is due for completion in 2025, with a masterplan that will provide 493 affordable homes. This is very much a community-oriented project, with the new homes planned around the the traditional concept of ‘streets and squares’, allowing mobility through and within the site. The buildings will feature predominantly brick and reconstituted stone façade materials, with natural light and open spaces that will make the homes feel welcoming and spacious. There will be one, two, three and four bedroom apartments, with maisonettes and gardens on the ground floor and those on the higher floors with full width balconies.
The highest levels of sustainability
By achieving Passivhaus standard energy performance, the development will meet the highest levels of sustainability and energy efficiency, addressing issues such as occupant wellbeing, climate action pledges and fuel poverty. A key element in meeting these standards is the avoidance of thermal bridging; and one of the most effective countermeasures has been incorporated – Isokorb technology from Schöck. Thermal bridging is not only a frequent cause of increased heat and energy loss, but condensation too. Leading to damp walls and the likelihood of mould formation, with its consequent health implications for tenants. Thermal bridges in the building envelope therefore have a measurable effect on energy efficiency and thermal comfort. Although their impact can be relatively low on buildings that are not well insulated, with buildings to the performance standard of Passivhaus the impact of thermal bridging is very significant.
Technically advanced solutions
With the Agar Grove development the risk of thermal bridging is primarily at the connectivity points involving balconies and parapets. Balconies are always likely to pose a risk when it comes to thermal bridging and it is here that the design detailing involves the first of the Schöck load-bearing structural therrmal break types used on the development – the XT type K. This transfers both negative moments and positive shear forces and has been awarded the "low thermal bridge construction" certificate by the Passivhaus Institute in Darmstadt, verifying its suitability for Passivhaus construction. A major reason for the superior performance of the product is the thickness of the insulation body, which is increased from the standard 80mm thick to 120mm. High quality stainless steel bars with improved tensile strength are an integral part of the unit. Although there is a smaller rod diameter and therefore a reduction in the thermally conducting cross-section, the same load-bearing capacity is maintained, resulting in a further increase in the heat insulation performance.
More thermally efficient than wrapped parapets
Where the parapets are concerned, the conventional method commonly used is to wrap the perimeter of the wall with an insulation barrier. However, by using the Schöck Isokorb XT type A, the solution is more cost-effective and offers a higher thermal efficiency than conventional wrapped parapets. Its 120mm insulation thickness results in low psi-values and therefore significantly reduces heat loss – and there is no wrapping required. It permits a more sophisticated construction opportunity for greater freedom of design and allows flexible distance between elements according to load requirements. An added benefit being there is no risk of any additional thermal bridging through balustrade fixings. Other key factors are durability and water impermeability, as the Isokorb solution used does not require maintenance and there is no risk of expensive restoration due to waterproofing problems.
Unquestionable environmental performance
Not only does the Isokorb range provide a number of solutions to meet Passivhaus standards, it also exceeds the requirements of the Future Homes Standard, helping the industry move towards the Governments 2050 net zero carbon targets. In addition to concrete-to concrete and maintenance free parapets, there are solutions too for concrete-to-steel, steel-to-steel – and innovative technology from Schöck even enables the retrofitting or renovation of balconies. Products meet full compliance with the relevant UK building regulations and there is also the security of independent BBA Certification, which provides NHBC approval. The requirement that the temperature factor used to indicate condensation risk (fRSI) must be greater than, or equal to, 0.75 for residential buildings, is easily met by incorporating the Isokorb.
Contact Schöck on 01865 290 890; or visit the website at www.schoeck.com for a full introduction to the extensive range of product solutions.