Which External Wall Insulation System?

If you are considering installing external wall insulation it is important to make sure you choose the right material and system for your property as well as choosing a quality contractor. There are lots of systems available on the market and here we look at some of the differences available…

EPS, Phenolic or Mineral Wool

There are three main types of insulation board – Expanded Polystyrene (EPS), Phenolic and  mineral wool

EPS is by far the most common and cost effective method available for insulating you home. EPS is made from small spherical beads which are steamed to expand them and then moulded in to slabs. This makes them easy to use and lightweight on the building

Mineral wool is made from molten minerals and spun into fibres. These fibres are then moulded into semi rigid batts which can be attached to the building. The products are more difficult to use and crucially are not as efficient in terms of insulation value as the EPS boards. They do however offer a more breathable solution.

Phenolic Boards are a dense material which is made through heat and pressure to layers of paper or glass cloth mixed with a synthetic resin. It is often used in the construction of new build houses to achieve the high thermal building regulations set out. Its advantage over the other materials is the fact that it can achieve the same Thermal Conductivity (U-Value) but with a much thinner board. When retrofitting External Wall Insulation, this can make a difference to the appearance of a system on the outside of your home. The downsides to installing this is it will attract a much higher cost per metre 2 to install.

The most common and cost effective therefore is to install EPS boards and in addition to being the cheapest, they are the easiest to work with and manipulate for shaping to a building.

What render should you choose?

There are typically 3 types of render which will be available to you

Mineral Render

Mineral render is fast set, cement based and polymer modified through coloured mineral thin coat render that can be applied at low temperatures. It is useful during colder months as it can be applied down to 0 degree. It is a usful product if installing when conditions are humid or cold as it will set fast and reduce the risk of a ‘wash-off’

Acrylic Render

Acrylic Render is a plastic enhanced material and is the cheapest of the 3 render finishes. Its advantage over the other two is its colour retention properties but it does have a major drawback with breathability and is not as flexible as the others which may lead to cracking over time.

Silicone render

Silicone render is the most expensive, but is easier to install than and has some unique advantages. It is breathable, is good at repelling dirt which gives it an element of self cleaning and it water repellent. It also is very flexible so for old houses that have been prone to cracking it is a very good option to keep its finish for a long lifespan