Why walls matter
Heat passes out through walls just as it does through the roof. Uninsulated walls can feel cold to the touch, make rooms harder to heat and, in some homes, contribute to cold spots where condensation and mould appear. Insulating walls can help, but the right approach depends entirely on how the walls are built.
Broadly, homes in the UK have either cavity walls, with two layers of brick or block and a gap between, or solid walls, usually found in older properties. Some have timber frames or other constructions. The first step is working out which you have.
It is also worth remembering that the loft is usually the simpler place to start. Wall insulation tends to be a larger, more involved job, so we often suggest looking at the roof space first and then deciding whether the walls are worth tackling.
The main types of wall insulation
Cavity wall insulation
Insulation is injected into the gap between the inner and outer leaf of a cavity wall. It can be a relatively quick job with little disruption inside, but suitability checks are essential. Cavities that are narrow, full of debris, bridged by mortar or already partly filled can cause problems, and very exposed walls facing driving rain need particular care.
Internal wall insulation
Insulation boards, or a battened system with insulation, are fixed to the inside face of external walls and finished with plasterboard. It suits solid walls and can be done room by room, but it reduces room size slightly and means moving radiators, sockets and skirting. Moisture control is important, so the build-up and vapour control need careful thought.
External wall insulation
Insulation is fixed to the outside of the walls and covered with render or another finish. It keeps the room sizes the same and wraps the house in insulation, but it changes the look of the building, involves scaffolding and detailing around windows, doors and roofs, and may need planning permission in some places, such as conservation areas.
Suitability checks come first
Getting wall insulation wrong can cause damp problems, so we take the checks seriously. During a survey we look at:
- the type of wall and, where possible, the cavity width and condition
- how exposed the wall is to wind-driven rain, which matters on the coast and in open, high positions
- the condition of brickwork, pointing, render, gutters and downpipes
- existing signs of damp, staining or mould inside
- whether the walls have been insulated before
If we see signs of damp, we will not guess at the cause. A qualified damp specialist or surveyor should assess it first. If a wall is not suitable for a particular type of insulation, we will tell you plainly.
Our process
- Free survey of the walls inside and out, alongside the loft if you wish.
- Plain-English explanation of the options that may suit your home, including any that do not and why.
- A written quote for the work we recommend, or a recommendation to involve a specialist.
- Installation by people suited to the job, following the product manufacturer's guidance.
Wall insulation is often worth considering alongside your loft insulation, since the roof is usually the simpler place to start. Our loft and condensation surveys can help build up a picture of where your home is losing heat.
Limitations
Wall insulation is a bigger decision than topping up a loft. It is not right for every home, results depend on construction and installation quality, and problems such as rain penetration, rising damp or structural cracking need to be dealt with by the right specialist first. External wall insulation may need permissions. We would rather recommend you do nothing, or start elsewhere, than fit something that is unsuitable.
Get honest advice on your walls
If you are wondering whether your walls could be insulated, book a free survey and we will talk you through it. Call 07835 254 241, email info@energyloftinsulation.co.uk or use our enquiry form.
Wall Insulation – your questions answered
How do I know if I have cavity walls?
Brick bond pattern, wall thickness and the age of the house can all give clues, but it is not always obvious. We check during the survey and explain what we find.
Can every cavity wall be filled?
No. Narrow, blocked or damaged cavities, very exposed walls and walls with existing damp may not be suitable. Proper suitability checks are needed before any cavity insulation is installed.
Does internal wall insulation make rooms smaller?
Slightly, as boards and plasterboard are added to the inside face of the walls. Radiators, sockets and skirting also need to be moved and refitted.
Do I need permission for external wall insulation?
Sometimes. It changes the look of the house, and in places such as conservation areas planning permission may be needed. Check with your local council before going ahead.
My walls are damp. Should I insulate them?
Not until the cause is understood. A qualified damp specialist or surveyor should assess the damp first, because insulating over an existing problem can make it worse.
