Keep Sheffield Warm

Cavity Wall Insulation - FAQs

Q Why should I have Cavity Wall Insulation installed?

A CWI is a proven technology giving benefits of a warmer, more comfortable home, significantly reduced heating costs compared to an uninsulated home (annual savings of around £115 and a payback period of little over a year with our "Snug-as-a-Bug" insulation grants, for a typical house) as well as reduced carbon emissions and an improved Energy Performance Certificate rating when you come to sell.

Q I am due to have CWI installed, but am concerned that it may damage my property, should I cancel?

A No - absolutely not, problems post installation are extremely rare. All systems are subject to technical approvals and in the context of the half a million installations carried out in the UK each year, very few have reported any concerns at all to CIGA who provide the independent 25 year guarantee.

Q I have booked to have CWI installed. How do I know that it will be done properly and I won't have any problems after?

A If your property has been deemed suitable then it has been assessed and passed as being suitable for CWI. All work is completed according to strict technical guidance issued by CIGA and all of our installations are covered by the Cavity Insulation Guarantee Agency (CIGA) for 25 years after installation. Therefore in the unlikely event of any problems with the materials or workmanship you have the comfort of knowing that CIGA is there to investigate and ensure that they are resolved.

Q What does the Assessment Cover?

A The majority of houses are suitable for CWI, and the assessment is designed to identify those that are not suitable. This involves a combination of visual checks, questioning and investigation that considers:

- Form of construction, age of building & structural condition
- Site conditions and Health & Safety considerations
- Extent of cavity to be filled and measurement of cavity wall area
- Outer and inner leaf
- Services through the cavity
- Ventilation and flues
- Means of space and water heating
- Modification to external walls since original build
- Extensions and additions.

Q How can I tell whether an assessment has been completed correctly and that it's safe to insulate my home?

A An experienced assessor can assimilate a lot of information based on knowledge of the locality, the construction practice at the time of build and inspecting similar properties in the locality. However, every building is different and the level of investigation required will vary, depending on many factors. It is also important that you answer any questions that the assessor asks about the property or its history as accurately and fully as you can.

Q Will I see the assessment?

A It is not usually necessary for a copy of the assessment to be provided. However, we would be pleased to answer any questions that you may have. For example:

- What is the minimum cavity width (the minimum that can be filled is 50mm)?
- Are there any areas that will not be insulated?
- How will the installing team deal with home improvements such as conservatories, car ports and air bricks etc?

Q How do I know that your company operates to the required standards?

A Keep Sheffield Warm is registered with the Cavity Insulation Guarantee Agency and as such we must abide by their guidance for the assessment of properties using the CIGA Best Practice Guide. [We are also members of the National Insulation Association and are similarly bound by their Code of Professional Practice]

Our company also undergoes regular inspection of the work we carry out on site and our office systems by the BBA. The BBA is an independent, non-profit distributing, product and installer certification body and certifies both the fitness for purpose of cavity wall systems and the adherence of installers to the requirements for installing such systems correctly. Details of BBA certified cavity wall installers can be found on the BBA website (www.bbacerts.co.uk)

Q Does Cavity Wall Insulation cause damp?

A No - definitely not.

Q Why doesn't Cavity Wall Insulation Cause Damp?

A All CWI systems are manufactured for the purpose and are water repellant. This is substantiated by independent water penetration tests carried out by the British Board of Agrément (BBA) which all systems must.

Q The cavity is there for a reason so why fill it?

A Cavity wall construction was introduced because it is impossible to build solid walls that do not allow a small amount of water through the mortar. With a cavity wall this water drains down the inner face of the outer leaf into the foundations. After CWI the same happens, with the water draining down the interface between the insulation and outer brickwork.

Q Can CWI cause a fire hazard?

A No.
- In traditional cavity walls the insulation is behind a masonry wall, having a fire resistance of 1-2 hours duration.
- The Blown Mineral Wools that we use are non - combustible. Tested to BS 476 : Part 4 : 1970.

Q What happens to a CWI installing company if they are found to have broken industry guidelines and codes of practice?

A If CIGA registered installers are found to be not adhering to the CIGA Best Practice Guides this would constitute a breach of CIGA rules. The company could then be required to rectify matters and could have their registration revoked.

The National Insulation Association (NIA) takes customer service and consumer protection very seriously and has a strict Code of Professional Practice that its members are required to comply with. The NIA takes any alleged breach of the Code of Professional Practice very seriously and has a formal process to fully investigate any claims and associated disciplinary powers which in the extreme case can involve termination of membership.

Under the BBA Cavity Wall Insulation Installer Scheme regular site and office inspections monitor whether the installer is following correct practice for the system being installed. Where best practice is not being followed corrective and preventative actions must be taken. Persistent failure to follow correct practice will result in the installer's certification being suspended or withdrawn. .

Q Can water penetrate mineral wool insulation?

A The material will not transmit water across the cavity by capillary action or from below damp proof course level. Any rainwater penetrating the outer leaf will drain harmlessly to the footings. The product is not designed to be a water vapour barrier.