Solid wall insulation

Insulating your solid walls could cut your heating costs considerably, because solid walls let through twice as much heat as cavity walls do. The good news is they can be insulated – from the outside.

If your home was built before 1920, its external walls are probably solid rather than cavity walls. Cavity walls are made of two layers with a small gap or ‘cavity’ between them. Solid walls have no such gap, so they let more heat through. Solid walls can be insulated from the outside. This will cost more than insulating a standard cavity wall, but the savings on your heating bills will be bigger too – Call DHR to enquire about grants that maybe available to cover the whole cost of the works!

How much could you save?

Type of solid wall insulation
Saving per year
Around £445
Around £475
Total cost including installation
£5,500 to £8,500
£9,400 to £13,000
Carbon dioxide saved per year
1.8 tonnes
1.9 tonnes

Estimates based on insulating a gas-heated, semi-detached home with three bedrooms.

External wall insulation involves fixing a layer of insulation material to the wall, then covering it with a special type of render (plasterwork).

External wall insulation:

  • ESWI does not reduce the floor area of your home
  • ESWI renews the appearance of outer walls
  • ESWI improves weatherproofing and sound resistance.
  • ESWI fills cracks and gaps in the brickwork, which will reduce draughts
  • ESWI increases the life of your walls by protecting the brickwork
  • ESWI may require planning permission - check with your local council
  • ESWI requires good access to the outer walls
  • ESWI is not recommended if the outer walls are structurally unsound and cannot be repaired