Why install external wall insulation?

External wall insulationInsulating your home could cut your heating costs considerably. About a third of all the heat lost in an uninsulated home escapes through the walls. Heat will always flow from a warm area to a cold one. In winter, the colder it is outside, the faster heat from your home will escape into the surrounding air.

Most modern houses these days are built with cavity walls. Cavity walls consist of two “skins,” separated by a hollow space (cavity). The skins are commonly masonry such as brick or concrete block. Cavity walls can be filled with insulating foam and this is known as cavity wall insulation.

However, if your house was built before the 1920s, it is likely to have solid walls, instead of cavity walls. Solid walls are notorious for letting through twice as much heat as cavity walls.

Solid wall insulation

If your home has solid walls, you can still insulate it using external wall insulation. External wall insulation involves fixing a layer of insulation material to the wall, then covering it with a reinforcement and a special type of render. The finish is usually a textured render, pebble-dash or sometimes a brick slip or a brick effect render finish could be used. These finishes can be used alone, or in a combination so that considerable variety in the appearance of the treated wall can be achieved. It’s just like wrapping your property up in a blanket to save energy and refurbish your property!

Benefits of external wall insulation

The key benefits of External Wall Insulation are heat retention and reduced fuel costs, indeed you can save up to £455/year* on your energy bills,  but there are a host of other benefits:

  • It can be applied without disruption to the household
  • It does not reduce the floor area of your home
  • Renews the appearance of outer walls
  • Improves weatherproofing and sound resistance
  • Fills cracks and gaps in the brickwork, which will reduce draughts
  • Increases the life of your walls by protecting the brickwork
  • Reduces condensation on internal walls and can help prevent damp (but will not solve rising or penetration damp)
  • Is best installed at the same time as external refurbishment work to reduce the cost
  • May need planning permission – check with your local council
  • Requires good access to the outer walls
  • Is not recommended if the outer walls are structurally unsound and cannot be repaired
  • Kind to the environment by reducing carbon dioxide emissions

External wall insulation cost calculator

If you’re considering external wall insulation, you can work out how much it would cost to install – just enter the dimensions of your property into our cost calculator and get an immediate estimate.


*These independent figures supplied by the Energy Saving Trust, 2016. Saving based on a medium detached house