Frequently asked questions

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What are the benefits of installing loft and cavity wall insulation?

There are many benefits including cheaper energy bills, warmer homes and reducing the effects of climate change. Rooms will warm up more quickly and the risk of mould forming condensation will also be reduced, benefiting some allergy sufferers and some chest complaints. Having cavity wall insulation may also increase the resale value of the property as you will get a better Energy Performance Certificate score than a similar house without loft and cavity wall insulation.

How can I be assured the installer is reputable?

All installers on this scheme are approved by your local authority in Greater Manchester and are subject to regular monitoring for the quality of their work as well as customer service standards. They are also members of the National Insulation Association. Should you have any problems, you should first approach the installer as it's their responsibility to resolve any issues, but if they do not meet your expectations, please do call the free phone advice line number 0800 009 3363 and let us know - we value your feedback.

What is a cavity wall?

A cavity wall means that the wall itself is constructed from two layers of brick (or one layer of brick and one of blocks) with an air gap or 'cavity' between them. The inner and outer walls are held together with ‘wall ties’ which bridge the air gap and hold the outer and inner skins together. To reduce the heat lost through the wall it is now common practice to blow insulating material into the cavity between the inner and outer walls.

What is cavity wall insulation made of?

The two most commonly used types of cavity wall insulation are:

Mineral Wool Fibre: water repellent and made from either molten rock spun out like candy floss or glass fibre, similar to that used for insulating lofts, chopped up and blown into to the cavity. Both of these types of mineral wool are know by different trade names but for insulation purposes they behave in the same way and have very similar insulating qualities.
Polystyrene Beads: similar to the beans found in bean bags but these have an adhesive applied when installed into the cavity to stop them being disturbed if any later work is carried out on the property, such as replacing doors and windows.

A qualified cavity wall insulation installer will be able to advise which type is suitable for your home.

Does cavity wall insulation deteriorate over time?

Modern cavity wall insulation is estimated to have a lifetime of around 40 years and comes with a 25-year independent (CIGA) guarantee.

Can all cavity walls be insulated?

Generally all traditionally built masonry (brick and/or block) cavity walls can be insulated but the width of the cavity must be at least 50mm (2in). Mortar or any other material blocking must be removed and any defects on the outer skin must be repaired before the cavity is filled. The height of the wall, and its exposure to the elements, will determine the type of insulation that should be used.
In some cases, if the walls have been treated with a chemical to eliminate ‘rising damp’ it may not be possible to insulate the cavity because of a possible chemical reaction. In addition, timber frame walls cannot be insulated even if they have a cavity. This is due to the slight risk of condensation or other moisture within the cavity affecting the timber frame.

How will I know if the walls of my house have cavities?

For the most part, houses built before the 1920s have solid walls constructed of brick or stone. After that time most houses were built with cavity walls. It is not always easy to recognise what kind of walls a house has. A qualified cavity wall insulation installer will be happy to check the suitability of the walls with no obligation.

Do I have to do anything before the installation of cavity wall insulation?

The drilling process can cause some vibration so it would be wise to remove ornaments for their safety and your peace of mind. Also, the insulation is only really effective if all walls are done – the installer will need access to all walls and need to get inside attached garages, lean-to sheds, conservatories etc. In some cases, the installer may need to access neighbouring property, so ask your neighbour in advance if this is okay.

Isn’t cavity wall insulation messy and inconvenient?

Cavity wall insulation takes half a day to install and you won’t have to leave the house. As the work takes place on external walls only, there should be no disruption or mess inside the house. A number of 18mm-25mm holes are drilled into the wall about 1.5 metres apart and the insulation is inserted into the cavity. The installer should ensure that all air vents and flues remain clear and, once the cavities are full, the holes will be filled so that they match the original finish as closely as possible.

What is loft insulation made of?

Loft insulation is mainly made of blown mineral fibre, also known as mineral wool, which has been treated with an adhesive. It is then formed into rolls of material for convenient handling. Where access is limited loose fill materials in a granular form can be blown into the loft space. These days there are a number of more environmentally friendly materials available, such as cellulose fibre, which is recycled paper treated to make it fire and vermin proof. Natural fibre insulation, such as hemp and treated sheep's wool are also now available.

How long will it take to install loft insulation?

It can take as little as an hour or two, but it will depend on the area of the loft to be insulated, its access and any other work required, such as pipe or tank insulation. Your installer will be able to give you a better estimate of how long it will take depending on your home.

I want to insulate my loft but I want to still be able to use it for storage – will this be possible?

Once the loft has been insulated to a minimum 270mm thickness the ceiling joists will no longer be visible, making the roof space hazardous to anyone attempting to enter. You could ask a local joiner to fit additional joists and floor boarding to help maintain your storage area. If you already have a boarded area of no more than a third of the loft area the installers can work around it and leave it uncovered.
An alternative method would be to place normal insulation between the joists up to their current height (100mm), and then lay a type of rigid, insulating board on top of the joists, followed by chipboard to give the storage surface. Insulating board can be purchased from major DIY chains.

My loft roof space is not big enough for an installer to stand up in. Will this be a problem?

It is fairly common that loft roof spaces are not big enough for people to stand up in. Most installers carrying out the work are in a kneeling position on walkboards and the industry usually work to a 1.4m height minimum.

I have quite a draught coming from my loft hatch. Can anything be done about this?

If you have your loft professionally insulated then upon completion of the work the installers will fit a draught excluder strip around the loft hatch (providing it is made of timber).

I am elderly and can’t empty my loft for it to be insulated. Who can help?

In general, if there are a small number of items and enough space, the installer will move them as he works. However, if there is limited space and too many items that will restrict movement they will have to be stored elsewhere during the installation. Organisations such as Care & Repair and Age UK may be able to provide the services of a handy man.

Can insulation help with condensation damp?

Yes. Insulation will not reverse any damage already done by condensation damp (for example mould growth or discoloured wallpaper), but it will reduce future damp as the insulation will help retain the heat in the wall and in the air in the house. Cavity wall insulation will ensure that the wall surface is warmer, and will therefore not encourage condensation to form. However, before cavity insulation can be installed a detailed survey should be undertaken to identify areas with damp or at risk of damp developing.

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

Cavity wall insulation must be installed for the full height of the building. In some instances it may be possible to insulate one end of a building, but not specific floors. Cavity ‘brushes’ can be used in the case of terraced and semi-detached properties to prevent the insulation material going into the cavities of adjoining properties.

What if I don't live in Greater Manchester – are there other offers available in my area?

It's probably best to call your local council – they will be able to tell you what's available locally to you.

My loft insulation only needs topping up? Can I have that done?

Of course. However, if you only need a top up then the grants are less and it may cost you between £60 and £145 (based on an average three bedroom semi-detached house). Get in touch with us for more information.

My home belongs to a housing association/local council. Am I eligible for free or discounted home insulation?

This scheme is available to homeowners and private rented tenants. Your housing provider is responsible for your home insulation. If you need further advice, you can contact us on Freephone 0800 009 3363.

Information supplied by the Energy Saving Trust. For more information on this and other energy saving advice go to www.energysavingtrust.org.uk