How to Lower Heating Bills in Older & Solid-Wall Homes in North Devon
A plain-English guide from Julian Smith of Red Sky Plastering & Damp Solutions – City & Guilds NVQ qualified, with over 30 years’ experience on North Devon homes.
In short: older homes with solid stone, cob or brick walls lose a lot of heat through the walls – the Energy Saving Trust puts it at around a third of all heat lost from an uninsulated home. To lower your heating bills and get a warmer home: fix any damp first, then insulate the walls (usually from the inside), use breathable materials such as lime and cork on period, cob and stone homes, and seal draughts around window reveals. We do this work across Barnstaple, Bideford, South Molton, Ilfracombe and North Devon.
Why do old and solid-wall homes lose so much heat?
Most houses built before the 1920s have solid walls – one thick layer of stone, cob or brick, with no cavity in the middle. Newer homes have cavity walls, which are usually filled with insulation. A solid wall has nothing to slow the heat down, so warmth from your radiators passes straight through it and out of the house.
That is why rooms in older North Devon homes can feel cold even with the heating on, and why the walls feel chilly to the touch. The Energy Saving Trust says homes built before 1920 are the most likely to have solid walls, and that a thin single-brick wall loses heat faster than a thick stone or cob one.
Is internal wall insulation the answer?
For many solid-wall homes, yes. Internal wall insulation means fixing insulation to the inside face of the external walls, then boarding and skimming over it so the room is ready to decorate. It cuts heat loss through the wall, so the room warms up faster and stays warm for longer.
It can be done one room at a time, it doesn’t change the outside of the house, and it is usually cheaper than external insulation. The trade-off is that the room loses a little floor space. You can see every stage of a recent job on our internal wall insulation project in South Molton – from the adhesive dabs on the bare wall to the finished skim.
What about period, cob and stone homes?
Traditional walls need to breathe. Stone, cob, old brick and lime all absorb moisture and let it dry out again. If you cover them with the wrong insulation or a cement-based finish, moisture can get trapped in the wall and cause damp.
We’ve been lime rendering for over 25 years, and on these homes we often use breathable materials. Cork insulation keeps heat in without trapping moisture, and lime render, plaster and mortar let the wall dry out naturally. On a five-month renovation in Welcombe we used eco-cork external insulation on some parts of a traditional cottage and lime mortar inside and out on the rest. Read more about our lime and heritage work.
Can dry lining make a room warmer?
Yes, if insulated plasterboard is used. Dry lining means fixing plasterboard to the inside of a wall – often with the dot-and-dab method – instead of plastering the masonry directly. Using insulated plasterboard adds a layer of insulation at the same time, and the boards are then skimmed smooth.
Why should damp be fixed first?
A damp wall is a cold wall. Water conducts heat much better than dry masonry, so a wet wall pulls warmth out of the room – and insulation fitted over a damp wall can trap the moisture and fail. The Energy Saving Trust is clear that damp problems must be solved before any wall insulation goes in.
We find the cause first, whether that’s failed render, leaking gutters, high ground levels or rising damp, and fix it. On an internal wall in Bideford, for example, we treated rising damp with silicone cream injection and replastered with a salt inhibitor and waterproofer. More on our damp proofing.
What about draughts around windows?
Window reveals – the short walls around the sides and top of a window – are a common weak spot. Gaps between the frame and the wall let cold air in, and thin or cracked plaster in the reveal lets heat out. When we insulate or dry line a wall we finish the reveals properly as well, so the window opening isn’t left as a cold spot. Keep any trickle vents and airbricks clear, though: a home still needs some fresh air to stay dry.
When should I call a professional?
The Energy Saving Trust advises that internal solid wall insulation should be fitted by a professional. Call someone in if:
- you have damp patches, mould or crumbling plaster
- your home is old, listed or built of cob or stone
- you’re not sure what your walls are made of
- you want to insulate more than a small area, or around windows and doors
A good installer will check the wall, deal with any damp, and recommend materials that suit how your home was built.
Frequently asked questions
Does internal wall insulation reduce heating bills?
Yes. Insulating the inside of a solid external wall cuts the heat lost through that wall, so the room warms up faster, stays warm for longer and needs less heating.
The Energy Saving Trust lists lower energy bills, less heat loss and fewer draughts among the benefits of solid wall insulation. How much you save depends on the house, how much of it you insulate and how you heat it.
How much heat is lost through solid walls?
A lot. The Energy Saving Trust says around a third (33%) of all the heat lost from an uninsulated home escapes through the walls.
Solid walls have no cavity to fill, so the only ways to insulate them are on the inside or the outside. Thin single-brick walls usually lose heat faster than thick stone or cob walls.
Will insulating an old house cause damp?
It can if the wrong materials are used or existing damp isn’t fixed first. Done properly – damp problems solved first, with breathable materials where the wall needs them – it shouldn’t.
Older solid walls made of stone, cob, brick and lime manage moisture by absorbing it and letting it dry out. Non-breathable insulation can trap that moisture. That is why we check the wall first and, on period, cob and stone homes, often use breathable systems such as lime and cork.
Is internal or external wall insulation better?
Neither is better for every house. Internal wall insulation is usually cheaper, can be done room by room and doesn’t change the outside of the house; external insulation doesn’t take any floor space but changes how the outside looks.
External insulation often needs planning permission and suits houses that are being re-rendered anyway. Internal insulation suits terraces, homes in conservation areas and anyone who wants to keep the outside as it is. We’ll talk you through what suits your home.
Do I need planning permission for internal wall insulation?
Usually not for an ordinary house, because it doesn’t change the outside. Listed buildings are different: internal changes to a listed building may need listed building consent.
Building regulations can also apply to some insulation work. If your home is listed or in a conservation area, check with your local council (North Devon Council or Torridge District Council) before work starts. We’re happy to talk through what is likely to be involved.
Who installs internal wall insulation in Barnstaple and North Devon?
Red Sky Plastering & Damp Solutions, based in Sticklepath, Barnstaple, installs internal wall insulation, dry lining and breathable lime and cork systems across North Devon. The owner, Julian Smith, is a City & Guilds NVQ qualified plasterer with over 30 years’ experience.
We cover Barnstaple, Bideford, South Molton, Ilfracombe and the surrounding towns and villages. Call 07881 688372 or 01271 314623 for a free survey and quote.
Book a free survey and quote
Want a warmer home and lower heating bills? Julian will look at your walls, tell you honestly what will work and give you a free quote.
Red Sky Plastering & Damp Solutions
16 Old Torrington Rd, Sticklepath, Barnstaple EX31 2DD
Call 07881 688372 or 01271 314623