Insulating your solid walls will make your home warmer and more comfortable, and greatly reduce your heating bills at the same time. Solid walls can be insulated in two different ways: with internal insulation or external insulation).
If you live in a house built before the 1920s, its walls are likely to be solid, with no cavity. Twice as much heat can be lost through an un-insulated solid wall as through an un-insulated cavity wall.
The most cost-effective way to insulate your solid walls is to do it when you are carrying out other repair or refurbishment work to your walls.
If you are re-plastering your internal walls, or changing major fittings in your bathroom or kitchen, these are perfect opportunities to consider installing internal wall insulation. Internal wall insulation can be carried out a room at a time, will not change the outside appearance of your home and can be installed by very experienced DIYers. It will however slightly reduce the size of the room and the installation process may disrupt room use – remember also that skirting boards and electrical fittings will need to be removed and reattached to the new wall surface.
If you are repairing or renovating external walls, especially if you have scaffolding, this is an ideal time to consider installing external wall insulation. External wall insulation can be installed without disrupting the household, increases the life expectancy of a property by protecting brickwork and provides extensive insulation without reducing living space. You may however need planning permission as it will change the outside appearance of your home.
There are two main ways to insulate a solid wall internally: with rigid insulation boards (plasterboard backed with polystyrene, polyurethane or foam), a stud wall (a metal or wooden frame filled with mineral wool fibre).
A layer of insulation material is fixed to the walls with mechanical fixings and adhesive, and then covered with a special type of render (plasterwork) or cladding – depending on the finish you prefer.
As they will cover the whole of the outside of your property, any of these finishes are likely to change its appearance – and will cover existing brickwork. So, you must ask your local council whether you need planning permission.
Solid wall insulation is not recommended for homes with structurally unsound outer walls that can not be repaired.
By reducing heat loss, solid wall insulation could save you around £500 and 2.6 tonnes of CO2 a year on your energy bills.
External solid wall insulation is NOT a job you can do yourself, and must always be carried out by a registered installer. Internal solid wall insulation is also usually installed professionally, and should not be attempted by the average DIY-er; only the very experienced should install it themselves.