Home Insulation

Insulation can help conserve heat in cold weather, helps prevent condensation on walls and ceilings, and can reduce the amount of heat building up in your home on hot summer days.

Are there any grants available?

If you are in receipt of an income-based benefit, live in Wales, and if your home is very energy inefficent (no insulation, single-glazing, old (or no) heating system, you may qualify for the Welsh Government’s NEST scheme if you need loft or cavity wall insulation.

Cavity Wall Insulation FAQs

Does Cavity Wall Insulation cause damp?

No. Correctly installed insulation will help to combat damp. Damp manifests itself in three ways. Rising damp (found mainly in older properties) is caused because there is no damp-proof membrane built into the walls at ground floor level. Water rises through capillary action and shows as staining up to one meter high on the inside of ground floor walls. Penetrating damp is the result of water penetrating walls through various means. Condensation is the result of warm, moist air coming into contact with a colder surface.

How will Cavity Wall Insulation affect the appearance of my house?

This will depend very much on the finish of the outside walls. The installer will try to match the existing finish. In most cases it will be difficult to see where the holes have been filled. Unlike, where wall-ties are replaced, very few holes are drilled anyway and the material which is drilled out to form the holes is used to fill them again after the insulation has been installed.

How long will it take to install Cavity Wall Insulation?

About two hours but it will depend on the size of your property and the area of the walls to be insulated.

What Is Cavity Wall Insulation made of?

The most commonly used types of Cavity Wall Insulation are “Polystyrene Beads” impregnated with an adhesive or “Rock Fibre” treated with water repellant.

How is Cavity Wall Insulation installed?

Measured amounts of the insulation material are blown into the cavity through a pre-determined pattern of holes in the outer wall. The installer will check that no air vents, flues etc. have become blocked. When the cavity is full the holes are filled so that they match the original as closely as possible.

Can insulation help with condensation?

Yes. Condensation is caused when water vapour in warm air condenses on cold surfaces. Insulation helps to retain heat so there will be fewer cold surfaces to support condensation.

What percentage of heat is lost through walls?

Uninsulated walls can lose up to 35% of the home’s heat. Proper wall insulation can reduce this by as much as two thirds.

Does Cavity Wall Insulation deteriorate over time?

No, but it may settle slightly. Cavity Wall Insulation will last the life of the building. A CIGA Certificate is issued for every installation guaranteeing materials and workmanship for a period of 25 years.

Can you insulate walls that were insulated 25 years ago?

This will not be necessary except, perhaps, where Windows or Doors have been replaced without due care being taken to ensure the insulation is not unduly disturbed. In the case where Polystyrene Beads have been installed, however, it may be difficult to prevent loss and more may need to be injected.

I live in a ground floor purpose built flat with cavity walls. Is it possible to get cavity wall insulation for just my flat or would it have to be for the whole building?

No, it is not possible to install Cavity Wall Insulation in one of a block of Flats. The owners of all the flats in the block would have to give their permission, and make a financial contribution, so that all the walls in the block could be insulated.

Loft Insulation FAQs

What is the percentage heat loss from the roof?

An uninsulated loft can lose up to 25% of the heat from the home. By insulating the roof up to the recommended 270mm (10½”) this could be reduced by as much as 15%.

How long will it take to install Loft Insulation?

About an hour but it will depend on the area of the loft.

Why should the pipes and water tank be insulated when my loft is insulated?

One result of insulating the loft is that the roof space will, itself, become colder. Any pipes and tanks in the loft will be more liable to freeze in cold weather. For this reason they, too, must be insulated.

My loft insulation has been topped up from 4 inches to 10½ inches. The additional insulation has been rolled out at 90 degrees to the original so that I can’t see the joists, why?

The most benefit from the additional layer of insulation is when the joists are covered too!

What is loft insulation made of?

Loft Insulation is mainly made of “Blown Rock Fibre”, which has been treated with an adhesive then formed into rolls of material for convenient handling. Some manufacturers supply the product ‘enveloped’ in plastic which can be likened to a very long pillow. Where access is limited other products, some times specially treated loose fill materials, such as granules, can be blown into the loft space.

Can you insulate between ceilings and the roof of a dormer bedroom constructed in a bungalow?

Generally, it is difficult and it could be costly to install insulation after the construction of a dormer bedroom. If there is sufficient space in the loft the room can be insulated. It must be remembered that when insulation is applied the loft space becomes colder and ample ventilation must be maintained to avoid condensation forming which could rot the timbers. A minimum of 50mm must be left between the ceiling of the room and the rafters. Each individual case will need to be assessed by a qualified Builder, Roofer or Carpenter who should be able to advise the best course of action and the cost involved.

If the joists in our loft are only 4 inches high, is it better to fit 4 inch insulation, or to compress the recommended 12 inches of insulation?

To obtain maximum benefit the space between the joists should be filled first. The extra thickness should be laid at 90 degrees covering the original layer and the joists. Consideration should be given to the position of electrical wiring and light fittings in the bedroom ceilings.

Is it possible to insulate a flat roof?

Flat roofs are often found on new extensions to older properties or on single storey and blocks of flats. Insulating this type of roof is more complicated than insulating roofs that have lofts.The best way to insulate it is on top of the roof as this keeps the structure of the roof warm too and lessens the risk of condensation. If the existing roof is sound then the insulation can be placed on top provided that it is held firmly in place, waterproofed and installed by a professional.

External Solid Wall Insulation

If your home has solid walls, then it is likely to be losing a lot of  heat.

Without a cavity to fill, the most practical solution is to clad the outside walls with insulation.

DSC04367.JPGThe first step is to fix the phenolic foam insulation boards to the outside walls


This is followed by a mesh reinforced cement based render coat for strength



Finally the decorative stone dash is applied.

The result is a warmer home with a virtually maintenance free-finish.


The energy saving can be around £280 a year. The warmer walls can also help reduce the risk of mould growth due to condensation.

Are there any grants available for solid wall insulation?

Over the past few years we have been able to secure funding to apply external insulation to many of the solid concrete homes in Newport. Unfortunately, there is no funding available at the moment.