It’s touted as an affordable home insulation method, but is external wall insulation worth the outlay and what are the lifetime costs? We look at the figures…

TIM PHILLIPS Is a quantity surveyor and runs Quantiv.uk, with over 30 years of experience across the commercial and residential sector. @timphillips71

In recent years, external wall insulation (EWI) has drawn a lot of attention as a practical and affordable way to increase a building’s energy efficiency. EWI has gained popularity for both residential and commercial structures because of the growing emphasis on sustainability and lowering carbon footprints.

EWI involves mechanically applying an insulation layer to a building’s exterior walls before covering them with a waterproof mesh and then finishing in cladding or render for protection. By preventing heat leakage through the walls, this layer of insulation helps to save energy use and heating costs. EWI can also improve a building’s visual appeal and offer more defence against deterioration and weathering.

However, a number of factors, such as the building’s size and type, the installation’s complexity, the material of choice for the insulation, and the desired finish, might affect the price of EWI. Generally speaking, EWI may require a larger initial expenditure than typical insulation techniques, but over time, the energy savings and increased comfort can frequently offset the additional costs In this article, we’ll examine all the factors that go into the final cost of an EWI project, examine various possibilities for finishing and insulation materials, and offer advice on how to set a budget. This will help readers to decide whether this energy-efficient solution is appropriate for their project.

TYPES OF EXTERNAL WALL INSULATION

There are a variety of EWI systems, each with their own unique benefits, drawbacks and features available. The following are a few of the more popular systems and an estimate of their costs. Expanded polystyrene (EPS) insulation is affordable, lightweight and simple to install. It is suitable for most types of homes, is very popular and is available in different thicknesses. When materials and installation are included, the price per square metre is usually £60–£80. Extruded polystyrene (XPS) insulation — compared to expanded polystyrene (EPS), extruded polystyrene (XPS) insulation has a greater compressive strength and moisture resistance and is normally used below your DPC. The average cost per square metre is between £80 and £100, making it more costly, but essential in protecting your damp-proof course.