Steel balconies

A common design feature in the UK is to connect a steel balcony to an interior concrete slab. Schöck Isokorb® type KS is the solution which thermally separates the exterior balcony from the interior slab. The main body of Schöck Isokorb® type KS consists of 80 mm thick EPS insulation. It offers high thermal resistance by using stainless bars to act as tension, shear and compression reinforcement.

A modelling study was undertaken by Oxford Brookes University to determine the effectiveness of Schöck Isokorb®. The aims of this investigation were to determine the heat loss, minimum surface temperature and hence temperature factor (fRsi) resulting from use of Schöck Isokorb® type KS14 units connecting a steel balcony support to a concrete floor slab. To simulate the real life situation for a balcony, the study included the glazing element as part of the building envelope.

Further information about the boundary conditions and the thermal conductivity of the used components can be found in reference 3.

From table 2 it can be seen that the Schöck Isokorb® type KS14 unit, with fRsi = 0.90, exceeds the minimum temperature factor value cited in IP1/06 (fRsi = 0.75) and will therefore meet the requirements of Building Regulations Approved Documents L1 and L2. The construction without a thermal break does not meet the temperature factor value required for dwellings. The heat loss by incorporating Schöck Isokorb® KS is reduced by almost 70%.