"Using External Wall Insulation on new builds."
External Insulation is not just for renovations. External Insulation can be used on new homes as well as for refurbishment of existing dwellings. Admittedly the default option in Ireland is to build a cavity wall. But this is not the way forward; it is very hard to do it correctly and very easy to mess-up. Plus it takes a lot of blocklayers skill to get the insulation right. The insulation needs to be flush against the inner leaf with no air gap to avoid something called “thermal looping”. Thermal looping will overwhelm any benefit from the cavity insulation leaving you with a more expensive un-insulated wall.
Cavity walls came in to use during the 19th century and gained widespread use from the 1920s. The primary purpose was to prevent the passage of moisture into the interior of the building. Since masonry is porous to water, the cavity is there to catch the water which passes through the outer leaf and keep the inside wall dry. Since then we have discovered that a cavity can also be filled with insulation to keep the house warm. Unfortunately we now have cavities that are used for both drainage and insulation! There is a lot of info on the web about the thermal flaws with cavity wall construction, but this paper by Joseph Little BArch MRIAI explains it very clearly.
In brief building a new cavity wall house is a missed opportunity to choose a more modern building technique
Our suggestion is to go with a single leaf wall say 215mm concrete block on flat for all external walls. On the outside you can have your choice of Insulation and Finish. The cost is no more than for a traditional wall, but you will have the assurance that the insulation actually works. 
In this way you can achieve any U-Value you want to, you can order any thickness of insulation and see for yourself that it is wrapped all around the house.
The advantages you gain by using External Insulation for new construction are:
- Simplifies construction: Particularly in terms of avoiding thermal bridging and achieving airtightness.
- Saves capital and running costs: Smaller heating systems can be used.
- Achieves high levels of insulation: Without increasing the size of the structure.
- Reduces labour and materials costs: Leading to a good value construction
- Usually eliminates the need for a vapour barrier: The dew-point is transferred outside the structure.
- Eliminates risk, as you can see exactly what has been built.
See here for a paper on External Insulation and New single leaf walls
Contact us now to learn how your home can benefit from External Wall Insulation.