Experts in Solid Wall Insulation

Around 30% of the energy used to heat a typical building is lost through the external walls. external wall insulation systems significantly reduce this energy loss by wrapping the building in a thermally resistant envelope, maximising the internal space, and maintaining comfortable internal temperatures all year round.

The External wall insulation systems we specify provide outstanding performance without compromising on aesthetics or the appearance of your property.

What sort of wall have I got?

The first question you should ask yourself, before thinking about wall insulation, is ‘what type of wall have I got?’

  • Solid walls were built up until the 1930s in most parts of the UK. By ‘solid’, it means that there is no cavity inside them. A solid wall’s brick pattern is recognisable by having lots of end bricks, which look like half-length bricks, in the middle of walls (i.e. not near ends of walls and not near windows and doors). These are in fact mainly cross bricks, which run from the front to the back of a wall. Therefore the depth of a wall – ignoring any plaster on the interior surface – is a brick’s length, about nine niches.
  • Cavity walls consist of an inner leaf an outer leaf, and a gap in between. Ties, which depending on the era are made of metal or plastic, hold what is effectively two walls together. The brick pattern shows many more full length bricks. Obviously the depth of the wall is greater, as most cavities measure at least two inches.

There are some other types of construction, such as timber frame and no fines, but these are comparatively rare. ‘No fines’ homes were more often built by local authorities in the 1940s and 1950s for council housing, and can be treated as solid wall for insulation purposes, although (uninsulated) they perform a lot better than older solid wall properties.

Solid wall insulation

If you have solid external walls, you have two options for insulating them:

  • Internal insulation, known as insulated dry lining, and external insulation (or insulating cladding). Insulated dry lining can be a do-it-yourself project but external insulation would not generally be a DIY option.
  • External insulation has the advantage of completely covering the facade of a home. Internal insulation is generally only installed within rooms. That leaves the opportunity for heat to seep out through other routes, e.g. via the voids between ceilings and floors, or in internal walls, and into the external walls, and then of course into the outside world. This escape of heat is known as the bridging effect.

External solid wall insulation

External wall insulation generally involves a wooden lattice being fixed to the exterior of the wall to hold some kind of solid insulation in place, and render or cladding over the top. There’s a wide variety of finishes, including brick and stone ‘slips’, so there will be one to suit most tastes or circumstances.

External wall insulation will add to the depth of your walls, so in some cases passageways and driveways will become narrower. Guttering and exterior drain pipes will probably need to be shifted outwards. There may also be the issues of the new exterior projecting over the public highway, or a home looking out of place in a terrace.

External wall insulation will usually radically alter the appearance of your home.

As a result you may need planning permission, so check with your local council. Windows will also change in appearance somewhat, as the insulation needs to wrap round into the window recess, to avoid the bridging effect.

This kind of insulation is sometimes done when there is a need to repair an existing render. It can also help greatly with protecting walls, although problems with damp should be put right first (e.g. with damp-proofing). External wall insulation prices are usually in the several thousand pounds range, depending on your home. The savings each year on heating bills will be considerable but it could still take more than twenty years to recover the cost. Therefore, the work is often best done during major refurbishments or during major repairs to the walls of a home.

Internal solid wall insulation

Internal solid wall insulation, or insulated dry lining, can also be costly but there is the opportunity to ‘do it yourself’. This brings down the ‘payback period’ by a great extent. If it’s done professionally, there will be disruption – much more than with external insulation – and it will probably take well over a decade to pay back at current wall insulation prices.

Insulated dry lining involves placing usually solid insulation against the inner side of a solid external wall, usually held in place with a wooden lattice. The lattice provides a mounting for plaster-boards, which go over the insulation.

However just behind the plasterboard there will also be a vapour membrane, to prevent condensation (interstitial condensation) occurring inside the wall and insulation structure, as a result of warm moist air in the house entering into parts of the structure which will of course be cooler, the further it gets. Sometimes special plasterboards backed with a vapour membrane are used, but this involves sealing the joins between the boards with specialist vapour impermeable adhesive tape, to prevent the warm moist air getting through at the joins.

Radiators, power and aerial sockets, shelves and other structures on the wall will need to be re-mounted on the new plasterboard.

Because of the vapour membrane, which can be punctured, you can’t put up shelves and picture hooks, etc. at a later date. Any work that might involve going through the membrane such as putting in new or extra power sockets, or mounting a new radiator, will also damage the membrane. Either the work should be avoided or the membrane re-sealed as part of the work. It is sensible to do the work as part of the fitting of the internal insulation.

Internal solid wall insulation prices are at an average around £5,500, but could cut your heating bill by almost 63.6% or up to £445 a year.