Space-age Solution to Coldbridging in External Wall Insulation
David Hilton explores a new coldbridging solution based on a material originally developed by NASA
As you read this column, hopefully you are enjoying the longer summer days. It is, however, at this time that we should be looking at the remedial actions that we can apply to our homes to make them more energy efficient in the heating season, especially if external works are required.
In generic terms there are two areas that impact on the efficiency of a home: insulation and draughtproofing. Insulation can realistically be applied either internally or externally. There can potentially be a third option, too: filling the cavity walls.
We have all probably put insulation in the loft (if you have one), as this is low hanging fruit and provides a relatively quick and cost-effective result with (usually) very little disruption. You may also have considered cavity wall insulation, but what can you do when you want an even greater improvement and a consistently better level of efficiency and comfort in your home?
Internal insulation will take up valuable room space and leaves potential cold areas (known as coldbridges) at internal partition walls, intermediate floors and at the plate levels where the wall joins the floor and roof.
The best option (which admittedly is not always possible and obviously impacts the appearance of the house) is external wall insulation (EWI). There are many different products available that can offer solutions for most construction types and ages. The wall is usually stripped back to remove any loose material and then prepared for the application of the insulation material. This commonly comprises rectangular blocks of around 600mm by 1m, with a thickness ranging from 50mm to over 200mm.
Once applied and finished, the solution will offer high levels of insulation but also improve airtightness. However, there are still potentially five areas of coldbridging to address.
Instagroup has developed a coldbridging solution that addresses these particular hard to treat areas by us- ing a very thin, high-tech insulation material, Aerogel, that was originally developed by NASA for the space programme and integrates seamlessly into its regular EWI systems. The Thermo-bead product is used around window reveals and door openings, while the Thermo-pro product is applied to soil pipes as well as eaves detail (especially where there is no soffit) and gutter boxes. Thermo-trac Base Rail is designed for use below the damp-proof membrane and Thermo-flash is specifically for use where walls and roof meet or link such as on bay windows and wall/roof junctions.
EWI is not cheap so if we are going to invest in efficiency then it is reassuring to know that all the details, including potential coldbridging can, and should be, addressed.