CAVITY WALL INSULATION FAQ's

What is a cavity wall
The external wall of a house is constructed of 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 22-26mm diameter and are ‘made good’ after injection. Each hole is injected in turn, starting at the bottom.

Is my house suitable?
Before the installation, our company will undertake an assessment of your property to confirm that it is suitable for insulation. This assessment may be undertaken by a surveyor or the 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 peace of mind.Our Technician will need 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 a wall right on the boundary, you may like to mention to your neighbour, that the Technician will need to go onto their property.

Are all the systems of insulation the same?
There are several different types of insulation:

•Bonded bead (white polystyrene beads)
•Glass wool (Yellow or white in colour)
•Rock wool (Grey/brown in colour)
•Urea formaldehyde foam (white foam)

Note: both glass wool and rock wool are known as ‘mineral wool’.
All systems of CWI have been tested, assessed and approved by the British Board of Agrément or the British Standards Institution. All are suitable for their purpose.Except for Urea Formaldehyde foam, the systems can be used in all parts of the UK. All systems have a similar insulation value but we use ‘mineral wool’ exclusively.

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.

What about the ventilators that are in the external wall?
Ventilators supplying combustion air to fuel burning appliances 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 a 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.

Do I apply for the CIGA 25 Year Guarantee?
No, we will submit the Guarantee application. The Guarantee will be posted to you shortly after the application is received at CIGA. - Keep it safe CIGA is non-profit distributing; its only function, is to stand as guarantor for the promises set out in the Guarantee. It has the resources to meet the promises made in the Guarantee. As a professional approved installing firm we are members of CIGA and can apply for a CIGA Guarantee, for properties built with traditional cavity walls. You should insist on a CIGA Guarantee, since nothing else can give you the level of assurance to which you are entitled.

How long will the insulation last?
For the life of the building - the British Board of Agrément say so.

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 on 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.

If I am concerned after the installation – what should I do?
Talk to us and give us the opportunity to investigate your worries.We will do all that we can to help you.

LOFT INSULATION FAQ's

What is the recommended thickness for loft insulation?
The current regulations under the EEC programme states that a minimum 270mm of loft insulation is required.

How much heat is lost through the roof?
As much as 25% of heat is lost through a roof which is not adequately insulated.

I already have some insulation in the loft but it is not very thick, will this have to be removed or can it be topped up?
Any existing insulation can be left in the loft and an additional layer added to it to bring it up to the required minimum thickness. It does not matter how long the existing insulation has been in the loft it still retains its insulant value.

I use my loft for storage but need to get it insulated, can I do this?
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. However it is possible to arrange for additional joists and floor boarding to be fixed via a local joiner 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 will work around it and leave it uncovered.

I have a cold water tank and pipework in my loft. Will these need to be insulated as well?
Yes they will. Any company who carries out loft insulation is responsible for insulating any tanks and pipework that is in the roof space to ensure it does not freeze come the winter period.

I have some lights within the ceiling (downlights) that protrude into the roof space. Will these cause any problems?
No. The installers will cut the insulation away from these leaving a gap of approximately 2” around the lights to prevent overheating.

I have sloping areas and flat roof areas within my property. Can these be insulated?
It is not always possible to do these areas. The reason being is that the timbers within these areas need to breathe and if loft insulation is fitted in these areas it can block the airflow off altogether. Access to these areas is usually minimal if at all existent. However every property has to be treated on an individual basis and the surveyor will make an assessment when visiting the property and advise accordingly.

My roof space is not big enough for an installer to stand up in. Will this be a problem?
It is very common that roof spaces are not big enough for anyone to stand up in . This is not usually a problem as the installers are usually working in a kneeling position on walkboards. Many companies within the industry work to a 1.4m height minimum for installers to gain access. It is very rare that a roof space is less than this.

Will I have any problems with condensation in my loft if I have it insulated?
Providing there is sufficient ventilation existing within the roof space, condensation will not occur. The installers are responsible for leaving all areas of ventilation i.e eaves level etc clear of insulation to maintain the current airflow. However if at the time of survey it is noticed there is already signs of condensation then the surveyor will advise of appropriate measures that are available to help cure this

My hatch is very small. Will the installers be able to get the insulation into my loft?
On rare occasions where the loft hatch is not big enough to get the insulation into the loft a new loft hatch can be created by the installing company at an additional cost.

I have quite a draught coming from my loft hatch. Can anything be done about this?
Yes. Upon completion of the work the installers will fit a draught excluder strip around the loft hatch providing it is made of timber.

Will there be much mess whilst the work is carried out?
Any mess created should be very minimal, as the installers will provide dustsheets to cover the areas of carpeting/flooring around the loft access areas to the door of entry to the property

How long will the work take?
Anything between 30 minutes to an hour and half depending on the size of the property and the amount of insulation being installed.

Is there any funding available to help assist with the payment of loft insulation?
There are various grants available at the moment but they all have individual criteria’s. The installing company will advise accordingly if you are able to access any of these.

DRAUGHT PROOFING

Where are the most common draughts found?
The most common place for draughts are around the frames of external wooden doors and windows. This is usually caused by either poorly fitted doors or windows, or seasonal variation. Other areas where draughts can be found are between the frames of doors and windows and the brickwork, also under the window sills. They can also be found where services or waste pipes come through the walls of the building draughts can be found.

How can I tell if there is a draught?
The easiest way to identify a draught is by wetting the back of your hand and passing it over the area where you suspect a draught may be, there should be a noticeable difference in temperature when a draught
is felt. Alternatively draughts can be identified by a professional who may use a smoke pencil or match.

How long will draught proofing measures last that I have installed?
Providing that the draught proofing materials are installed in accordance with manufacturers instructions it would be realistic to achieve a life expectancy of between 5 – 10 years. However it would be recommended
to look for products carrying the British Standard Kite Mark BS7386 these products can last up to twenty years.

What types of draught proofing materials are there available?
There is a wide and varied selection of draught proofing materials available. It would be recommended that you first look for products manufactured to BS7386. These will take into account seasonal gap variation and give you a long life expectancy, secondly ease of installation and finally ease of maintenance. There are products available that can even be painted or stained.

Will this affect my gas fire?
Most fuel burning appliances with more than 7kw output require permanent fixed ventilation; if you are unsure consult your Corgi registered gas installer before proceeding with your draught proofing installation.

If you find that your question still remains unanswered please do not hesitate to contact us on 0800 093 9830.