Why are thermal breaks in structural balcony-type applications often disregarded?

“Man darf nie beim Alten stehen bleiben” (“You must never remain standing still”), a quote that visitors are greeted with when they are guided through the innovative museum of German-based thermal break solutions manufacturer, Schöck. These are the wise words of the company’s Founder, Eberhard Schöck, and this message is unmistakably the ethos behind the company’s groundbreaking thermal solutions.



ack in July, FC&A was invited to the specialist’s headquarters in the picturesque, quaint German town of Baden-Baden, where the birth of Eberhard Schöck’s thermal break creation began its life.

The company’s success in innovation and production is evident through the vast volume of thermal break solutions it produces on a daily basis for construction sites in every corner of the globe. Globally recognised amongst the most prestigious of clients from within the construction industry – having supplied solutions for projects from London to Moscow – Schöck is constantly developing its production line to ensure its products meet the ever-evolving, stringent Building Regulations in countries such as Poland, Germany, Switzerland and the UK, to name but a few.

Schöck’s main product – its thermal break solution, Isokorb – was a concept conceived by Eberhard Schöck. The notion arose whilst the German entrepreneur was on a skiing vacation in Switzerland. Eberhard encountered a Swiss hotel accommodating a number of balconies and expressed concerns over energy loss and internal mould from within the establishment. Four years after his discovery, Eberhard launched the company’s very first thermal break solution, Isokorb.

Since Eberhard’s discovery, there has been an increase in awareness around the importance of thermal breaks, however, what was apparent from FC&A’s visit is that many industry professionals – particularly within the UK – are still unclear of the importance of thermal breaks and the impact they can have on our buildings.

This disregard of thermal breaks within structural balcony connections may stem from a lack of understanding from within the UK construction industry or by using inappropriate ‘thermal break’ solutions out of ignorance.

One example of such a ‘thermal solution’ commonly being used within UK architecture was brought up by Schöck’s UK Managing Director, Chris Willett. “Architects often don’t fully understand thermal breaks,” he explained, “and, as a result, thermal ‘pads’ are commonplace in UK architecture. As the industry demands for thermal efficiency become greater, under certain conditions, pad solutions may not be sufficient to meet the Part L requirements of the UK Building Regulations in balcony construction.

“While architects may think that they are specifying a thermal break that meets the requirements, this may not be the case. Schöck’s thermal break solutions, on the other hand, are independently verified to be fit for purpose, are manufactured using insulation and do meet the relevant Building Regulations.”

It is evident from Chris’ disclosure that there is still a need to educate the architectural industry in the requirements of the Building Regulations to ensure correct specification of thermal break solutions, that are proven to meet Part L.

So, what is a thermal break?

By definition, a thermal break is a localised area with a higher thermal conductivity than the adjacent areas – in other words, a material of high conductivity, such as a balcony or any other form of a structural attachment, that penetrates an insulation layer.

The use of a thermal bridge within a structure will enable a positive heat transfer through the structure and permit cooler surface temperatures on the warm side of the structure. However, negligence when it comes to thermal breaks can lead to several repercussions, namely:

  • Higher energy use for heating and cooling, resulting in inflated utility bills
  • Cold surfaces, leading to end-user discomfort
  • Condensation, which can lead to corrosion and decay
  • Mould growth, which comes with health concerns and impacts the durability of building materials
  • Importantly, it is not compliant with UK Building Regulations. If architects and construction professionals are not considering thermal breaks, they will not meet the carbon emission targets set out in Part L.

Schöck’s solutions

By thermally separating an exterior and interior structure (such as balconies and parapets) you will be creating a thermal break between the two structural components. By including a thermal break solution, the thermal losses at the connections of a structural element will be significantly reduced.

Schöck’s thermal break solution, Isokorb, is produced using expanded polystyrene (EPS), with a minimum thickness of 80mm. EPS is used for the main body of the product, while reinforcement bars are used to conserve the integrity between the structural elements of a building.

As well as boasting heat-insulating properties, Schöck’s Isokorb range also acts as a load-bearing element for cantilever balconies meaning the Isokorb itself forms part of a building’s structure.

The range is available in 10,000 standard variations – adhering to Building Regulations in multiple countries. Comprising five main solutions, including bespoke options, the range includes:

  • Isokorb 80mm – applicable for concrete-to-concrete applications, with an 80mm-thick insulation layer
  • Isokorb XT 120mm – again, applicable for concrete-to-concrete applications, with a 120mm-thick insulation layer
  • Isokorb Type KS and QS – for concrete-to-steel and concrete-to-timber applications, with an 80mm thickness insulation layer
  • Isokorb Type KST – for retrofit applications
  • Isokorb R – for the renovation of concrete-to-concrete and concrete-to-steel applications.

Educating the industry

Schöck’s in-house-designed software, available for architects and construction professionals, is able to calculate heat loss in buildings according to the Standard Assessment Procedure (SAP) requirements and is tailored to UK weather conditions.

Industry professionals can delve deeper into the world of thermal breaks at The Institute of Structural Engineers’ (IStructE) event in November where Schöck will be hosting a workshop on thermal solutions. The event is free to attend and architects will can gain CPD points for participating.

Enhancing energy efficiency

Schöck’s aim is to improve the energy efficiency of buildings both in the UK and internationally, and its Isokorb range is backed up with British Board of Agrément (BBA) approval across the range, as well as extensive thermal modelling research from Oxford Brookes University.

An innovation that initially began its life in 1983, and took approximately 35 to 40 minutes to install, has evolved into an easy-to-handle product taking around three to five minutes to position.

It’s not often that many find a solution to construction issues, however, Eberhard Schöck has proved that innovation can lead to the most effective results.

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