What is a cavity wall?
The external wall of a house is constructed of two masonry (brick or block) walls, with a cavity space of at least 50mm between, and held together by metal wall ties.
Are all houses suitable for cavity wall insulation?
No. If the house is not of traditional construction as above, it is unlikely to be suitable. The following types of property are not suitable for cavity fill: timber frame, steel frame, and random stone.
I have a Conservatory on the rear of my house. Will this affect my installation?
Any areas which prevent access to the walls such as conservatories, outhouses, garden sheds etc., may prevent that wall area from being filled. If the building area is less than 3m long then we can use tower scaffold to access the wall, but if it is too big for tower scaffold then we will exclude that area of wall and ”barrier it off” with cavity barriers.
Do I need to make any preparation for the installation?
The-drilling process can create some vibration on the external walls, so we advise that you remove any ornaments or breakables prior to drilling taking place, just to be on the safe side. If our installers need to gain access through your neighbour’s property or from their drive/garden, please ask them for permission and make sure that this is acceptable prior to installation.
Do I need to be at home for the installation?
Yes. Our installers need to check your gas appliances and make sure your walls are clear before they start installing cavity wall insulation.
My house is semi detached / terraced, will the cavity wall material go into my neighbour’s walls?
No – if the neighbour’s house is already insulated then our material will stop where it meets theirs. If it is not already insulated, our installers will fit a cavity barrier at the party wall line, usually made from bristle brush. This will prevent any trespass of material.
What type of material do you install?
We install either glass fibre or mineral wool. They allow the walls to breathe and are waterproof so no water can ”soak” through the material.
Is the cavity wall insulation guaranteed?
Yes – a Guarantee is provided by CIGA (Cavity Insulation Guarantee Agency) – this is a 25-year guarantee and applies to the property, not the person, so you need to keep it safe with other documents for your property. You will need this document if you sell your house. We will apply for the Guarantee on your behalf.
How do I know that the walls have been filled properly?
Our installers drill out a defined pattern of holes, which ensures that the insulation fills all wall areas properly. They carry out a density check on a test box, to make sure that the machine is blowing the material at the correct level.
How long does cavity wall insulation last?
For the lifetime of the building.
Will the drilling make a mess of my walls?
The installers will fill the injection holes with mortar to match the existing finish as closely as possible. He will use a mix that closely matches the existing colour and texture. On pebbledash walls the installer will texture the mortar to try and match the pebbledash. After weathering, the holes are difficult to see.
Will my gas appliances be safe after installing cavity wall insulation?
Yes. Our installers will carry out gas spillage tests on your gas appliances both before and after the installation, to make sure that they are working efficiently and safely. If there are any problems with ventilation, they will advise you. If your appliance is over 7kw, you will require a Combustion Vent to be fitted in your wall to allow sufficient ventilation. Our surveyor will advise you of this.
Will the cavity wall insulation block my under floor vents?
No – our installers will check your vents to see if they are sleeved. If not, they will remove the vents and replace them with new ones after fitting material sleeves inside the cavity. This will prevent material from blocking the vents.
How long will it take to carry out the installation?
Most properties take around 2-3 hours, but it depends on the size of your home and whether there are any access restrictions.
How will I know if my house is suitable?
We will send a surveyor to assess your property. He will carry out a full borescope survey by drilling a hole in your wall and checking it with a camera to see it is suitable.
CIGA (Cavity Insulation Guarantee Association)
Our approved installers provide a CIGA Guarantee for cavity work carried out. For the cavity wall fact sheet CIGA-Fact-Sheet.
Do I need to make any preparation for the installation?
The installers need good access to the loft so you may need to remove items stored in the loft if you have a lot of them. If you have only a few smaller objects stored then the installers can probably work around these and move them whilst fitting the material.
My loft has boarding for storage, what will happen to this?
You should remove the boarding so that we can fit the material throughout the whole of the loft. You will not be able to refit the boarding over the new loft insulation, as the material will compress onto the ceiling boards and may cause damage to your ceiling. If you are unable to remove the boarding, we may be able to lay material over the top; however you will not be able to use the area for storage afterwards.
Can I use my loft for storage after the installation?
The material is Cross-Laid; this means that you will have a layer of material between the joists, with another layer fitted at right angles to the first layer, over the tops of the joists.
I have a false ceiling, can this be insulated?
We cannot insulate a false or suspended ceiling as there is no safe access for the installers, nor is it safe to lay the material onto these.
I have down lights in my ceiling; will this prevent the insulation from being fitted?
We can still install loft insulation if you have down lights fitted through your ceiling. Our installers have to cut around the light fittings and ensure that they are not covered by our insulation material. Ensure that our surveyor notes this when he comes to see you.
My roof is very low; can the installers still fit insulation?
Our surveyor will go into your loft to check the access at the time of survey.
What happens to the tanks and pipes in the loft?
We need to ensure that your tanks and pipes are adequately insulated. Our installers will fit new insulation if your existing pipe and tank insulation is not up to the required standards. We will also fit insulation material to the back of the loft hatch; this is usually stapled to prevent it from falling off the hatch.
What material do you install?
We use glass fibre rolls which are usually opened in the loft thereby preventing any loose fibres from getting into your home. On occasion, if necessary, we may use blown fibre for difficult access areas.
Complete our 30 second short form or call our friendly UK team 24 hours, 7 days a week free on 0800 612 7878 and our grant staff will call you back within 1 hour and book your free survey at a convenient time and date.