It’s all Greek to me! What has Achilles got to do with external wall insulation?

Blog Post
Statue of Achilles

When you’re working with thermal insulation, you may have come across Lambda, Psi and Kappa values. Similar to mathematics, these values are all part of the Greek alphabet and are used to define performance levels of insulation products when they’re used on their own or in combination with other materials. 

External wall insulation (EWI) is becoming a common method of upgrading poorly insulated homes. 

As long as you have the extra space to add a “tea cosy” over the house then energy bills can be cut drastically and all your problems should be over!

Image showing areas of heat loss in a home

Achilles' heel

The famous Greek character Achilles was invincible except for one weak spot that ultimately became his downfall.

Just like Achilles, in the thermal image you can see the heat (yellow/red) escaping below the damp proof course. In fact the junction between the floor and the external wall can account for as much as 34% of overall heat loss where materials meet one another if cold bridging is not eliminated.  

Before installing an EWI system on any building, a solution should be developed that suits the age, condition and the construction material used in the building. These are all essential considerations in a thermal upgrade. If the solution isn’t tailored to your building or a specialist insulation manufacturer doesn’t have a solution to a particular point in a building, then this detail tends to be ignored.

The Achilles Heel in their methodology in turn becomes the Achilles Heel in your building, leaving it vulnerable to damp, cold and deterioration due to mould or heat loss.

InstaGroup Limited have researched and developed, a range of innovative anti-cold bridging products that provide a suite of solutions for their All Weather External Wall Insulation system, which when pieced together, achieve continuous insulation on their projects.

This system has just received an LABC Registered Detail, now known as LABC Assured (as of March 2019), which is accepted by every building control team in England & Wales. The system also has a BBA Agrément approval.

Installation using InstaGroup Thermo Trac at damp proof course level

Thermal image with InstaGroup Thermo Trac damp proof in place

During the design process InstaGroup Limited guide clients through the decision process based on factors such as budget, breathability, character, space and so on to help you decide which solutions best fits your requirements.  

Lucy Shadbolt, Director of Green Deal at InstaGroup says “It’s about the return on your investment. We all want maximum return when we invest time or money in a project don’t we? We want to provide you with a long-term safe investment that will continue for the lifetime of your building. Otherwise, like Achilles, all your good work can be undone when a vulnerability is exposed.”

Further information

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Please Note: Every care was taken to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the dutyholder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.



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