Your Questions Answered

WHAT IS A CAVITY WALL?
The external wall of a house is constructed to two masonry (brick or block) walls, with a cavity (gap) of at least 50mm between. Metal ties join the two walls together.

HOW IS CAVITY WALL INSULATION INSTALLED?
The cavity wall is injected with insulating material by drilling holes in the external wall through the mortar joint. Holes are generally of 22mm - 25mm diameter and are 'made good' after the injection. Each hole is injected in turn, starting at the bottom.

HOW LONG DOES IT TAKE?
Cavity wall insulation normally takes around two hours to install but the time does depend on the size of the house and other factors, such as access.

IS MY HOUSE SUITABLE?
Before the installation, the we will undertake an assessment of your property to confirm that it is suitable for insulation. This assessment may be undertaken by a surveyor or technician before installation.

DO I HAVE TO DO ANYTHING BEFORE THE INSTALLATION?
The drilling process does create some vibration - so it would be wise to remove ornaments, particularly on external walls, for their safety and your piece of mind.
The technician will need to access to all walls, so he will need to get inside attached garages, lean-to sheds, conservatories etc. The insulation can only be really effective if all walls are done. If you have wall right on the boundary you may like to mention, to you neighbour, that the technician will need to go on to their property.

IS THERE MUCH MESS?
The drilling process inevitably creates a little dust, which will be cleaned upon completion of the job. It may be wise to remove vehicles from the drive and things close to the walls. This will also give the technician better access for equipment and tools.

DOES THE TECHNICIAN HAVE TO COME INTO THE HOUSE?
The technician must undertake checks before and after installation, including any heating appliances, so it is essential that they have access inside the property. Apart from these checks, all the remaining cavity wall insulation work is carried out from the outside.

MY HOUSE IS SEMI-DETACHED. HOW DO THEY STOP THE INSULATION GOING IN TO NEXT DOOR'S CAVITY?
Assuming your neighbour's house is not already insulated, the technician will insert a cavity barrier at the party wall line. This is usually a length of bristle brush. Of course, if the neighbour's house were to be insulated at the same time, the cavity barrier would not be needed.

ARE ALL SYSTEMS OF INSULATION THE SAME?
There are several different types of insulation available. We have chosen InstaFibre White Glass Wool. All systems of CWI (Cavity Wall Insulation) have been tested, assessed and approved by the British Board of Agrément (BBA) or the British Standards Institution (BSI).

ARE THE TECHNICIANS TRAINED?
All our technicians undergo training by the system supplier to ensure they are competent in CWI and carry a training and identification card. Please feel free to ask to see this information.

HOW DO I KNOW THE WALLS ARE FULL?
Each system has a defined pattern of holes, which has been tested to verify that it results in a complete fill. Most systems have an automatic cut out, which actuates when the adjacent wall area is full. There is tolerance in the injection pattern so that the material will flow past the next injection hole.

IS THE INSULATION DENSE?
No, as the insulation is contained within a masonry wall, it doesn't need to be 'dense'. For insulation and other purposes, a light density is better. Before insulation, the technician will undertake a quality test to ensure the insulation will go into the wall at the right density. He will also note the amount of material used, to know that sufficient insulation has been installed.
Note: Drilling a hole in the outer wall and testing the cavity fill with a rod or pencil may not provide any meaningful information.

WHAT ABOUT THE VENTILATORS THAT ARE IN THE EXTERNAL WALL?
Ventilators supplying combustion air to fuel burning applications must be safeguarded. Similarly ventilators at ground level that ventilate below timber floors must be safeguarded. The technician will investigate them to check they are already sleeved. If they are not, the technician will remove them and seal around them to stop them being blocked by the insulation. Other vents, which may be redundant, such as cavity vents or vents that used to supply air to open fires in bedrooms may be closed off. The technician should discuss these with you. Redundant airbricks may be filled.

WHAT ABOUT FILLING THE HOLES?
The technician will fill all the injection holes with mortar to match the existing as closely as possible. He will use a mix that closely matches the existing colour and texture. On pebbledash finishes, he will apply pebbles to the surface to match the existing finish. After weathering, the holes are difficult to see.

BUT MY HOUSE HAS PAINTED AREAS?
Normally, we will not paint the injection holes. Unfortunately, even if the original paint is used, it may not match due to weathering. So it may be necessary for you to consider painting the area, after the mortar has dried. You should discuss and agree what will be done with the installing firm.

DO I APPLY FOR THE CIGA 25 YEAR GUARANTEE?
No, we will submit the guarantee application. The guarantee is posted to you within 6 to 8 weeks of the application being received at CIGA. Keep it safe!

WILL MY HOUSE BE WARMER?
Yes - if your heating is not controlled by a thermostat. However, if you have a thermostat, it will cut out the heating at the same temperature, so you may not notice the difference in the room with the thermostat. However, you should find that the temperature in other parts of your house improves, for example, the small bedroom in the corner.
With CWI, you should find that the house holds its temperature for longer, therefore the time between heating cycles may be longer. The result should be a more even temperature throughout the house and/or a reduced fuel bill.

ARE THERE ANY MAINTENANCE OR SERVICING REQUIREMENTS?
No, not to the cavity wall insulation, but normal building maintenance is needed.

HOW LONG WILL THE INSULATION LAST?
For the life of the building - the BBA say so!

IF I AM CONCERNED AFTER THE INSTALLATION, WHAT SHOULD I DO?
Ring us free on 0845 662 3613 to arrange for our inspector to come and carry out a free inspection of the work.