Foster House Residential Development, Hertfordshire

Foster House Residential Development, Hertfordshire

Client: Hertsmere Council
Type of works: supply of Schöck’s Isokorb® thermal-break module type KS, for concrete-to-steel connectivity.

The Schöck Isokorb® thermal break module type KS, for concrete-to-steel connectivity, has been combined to good effect with Holorib decking for the balcony construction of an extensive new residential development at Borehamwood in Hertfordshire. This is the first project in the country where the Isokorb® has been used in conjunction with Holorib, which provides permanent shuttering and is an extremely strong profile allowing the design of a thinner slab.

Foster House, in Maxwell Road, provides 114 one- and two-bedroom flats, all of which meet with level three of the Government’s Code for Sustainable homes. The Code measures the sustainability of a new home against nine categories of sustainable design, rating the whole home as a complete package.

Cllr Hannah David, portfolio holder for housing and planning, said: "Hertsmere as a council is required to build thousands of homes in its borough to meet government requirements so it is very important to us that what we provide is to a high standard and right for local communities. This particular development is to a very high standard and in a great location. We hope that people will enjoy living there."

The type KS Isokorb® from Schöck provides a structural, thermally efficient connection for the steel balcony to the composite slab. The product is simply positioned within the Holorib decking and tied to the slab reinforcement. The design and detailing of this connection is carried out, in conjunction with the project engineer, by the Schöck team of structural engineers at the design office in Kidlington. The KS is fully BBA certified, maintenance free, and once installed can be fine tuned and adjusted to optimise fitting tolerance.

Isokorb® modules meet full compliance with the relevant UK building regulations. These require that the temperature factor used to indicate condensation risk (fRSI), as described in BRE IP1/06 – a document cited in Building Regulations Approved Documents Part L1 and L2 and Section 6 in Scotland – must be greater than, or equal, to 0.75 for residential buildings. With the type KS Isokorb® the temperature factor (fRSI) is in excess of 0.91 and furthermore enables optimum compliance with the Building Regulations Approved Documents by using numerical modelling to calculate the building’s energy performance.

There is also compliance with the Government Standard Assessment Procedure, SAP 2009, concerning CO2 emissions from buildings, and respectively heat losses through non-repeating thermal bridges. Here, the lambda values of the Schöck Isokorb® enables energy loss through balconies, canopies and other cantilever parts of buildings to be reduced by as much as 84% to 91%.

In addition to its exceptional thermal performance ratings, the Schöck Isokorb® range is also unique on two counts. It is the only range to provide thermal break solutions for connections between concrete-to-concrete, concrete-to-steel and steel-to-steel – and it is also able to offer BBA Certification.

A 20 page ‘Specifiers Handbook‘ is available which provides an overview and introduction to the Schöck Isokorb®, and there is a comprehensive 236 page ‘Technical Guide’ which displays in detail the complete range of thermal break applications for all construction types – concrete-to-concrete, concrete-to-steel, steel-to-steel and concrete-to-timber.

For further information about services from Schöck, or to request a free copy of the Specifiers Guide and/or Technical Guide; contact Schöck Ltd on: tel: (0845) 241 3390; fax: (0845) 241 3391 or visit

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Schöck provides a market-leading range of load-bearing thermal break modules known as the Isokorb. It is unique in that it allows connections to be made between concrete-to-concrete, concrete-to-steel and steel-to-steel – and also provides BBA...
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