EWI – External Wall Insulation

January 12th 2015

Pennycuick Collins Building Consultancy Department are currently overseeing the installation of External Wall Insulation (EWI) to a 1960’s residential apartment block within the Birmingham area. A green deal grant has been obtained to fund this project.

External Wall Insulation is installed using sheets of insulation board fixed to the outside of a buildings walls, protected with layers of render or cladding to provide an attractive finish to benefit the overall external appearance.

The advantages of installing EWI on a property are numerous and wide-ranging. EWI insulates the walls which help to reduce heat loss in cold weather and heat gain in warm weather. The result is a much more comfortable living environment within the home with less risk of condensation and damp wall and a reduction in heating costs by up to as much as 40%.

Draft regulations which have not yet been published although widely reported and as stated on the Department of Energy & Climate Change (DECC) website, state that Section 49 (4) of the Energy Act 2011 is to prohibit the letting of property where the rating on an Energy Performance Certificate (EPC) is below band E. By installing EWI it will ensure that the building complies with the current requirements of the Building Regulation (Part L) and reduces the EPC rating and U-values.

U-value is a measurement of heat loss through the walls, floor or roof of a building. The lower the U-value, the greater the resistance to heat loss and the less it will cost to heat the building. A solid brick wall will typically have a U-value of 2.0W/m²K and installing EWI can reduce this to 0.35W/m²K or better which could cut heating costs by up to 40%.

Written by Guy Travis MSc – Building Consultancy