Green Deal FAQs

Can the different materials used for CWI cause a fire hazard?
  • In traditional cavity walls the insulation is behind a masonry wall, having a fire resistance of 1-2 hours duration.
  • Blown Mineral Wools are non – combustible. Tested to BS 476 : Part 4 : 1970.
  • The use of expanded polystyrene beads (EPS beads) for CWI does not prejudice the fire resistance properties of the wall. The beads will shrivel in the face of heat, returning to their original unexpanded form.
Does Cavity Wall Insulation cause damp?
No, definitely not
Why doesnt Cavity Wall Insulation Cause Damp?
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 Agrement (BBA) which all systems must undergo
The cavity is there for a reason so why fill it?
Cavity wall construction was introduced because it proved impossible to build solid walls that did 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.
I recently had CWI installed, does this mean I might suffer damp problems?
No, problems post installation are extremely rare. CWI is a proven technology giving benefits of reduced heating costs. (It can save around £145 a year and pay for itself in around two to three years) and reduces carbon emissions. All systems are subject to technical approvals and in the context of the several hundred thousand installations carried out in the UK each year very few have reported any concerns at all to CIGA. However should you experience any problems in the future, contact the installer immediately and they will arrange to investigate this for you and resolve any problems due to the CWI
I recently had my home insulated with CWI and I don´t think an assessment was done, what can I do?
Industry assessment procedures are robust and many aspects are taken into account. However, 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. Therefore, where the property is straightforward and well maintained, the assessment procedure will take less time than for a complex building which has existing structural defects.
What are the signs that your cavity wall insulation may be damp?
If a property is suffering from a damp problem it is highly unlikely to be caused by the CWI. Government research looked at 30,000 properties and concluded that the incidence of water penetration was very low, and there was no additional risk of rain penetration if the cavities are filled. The materials used are resistant to water penetration and is subject to testing to ensure that it 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.
How do I know that your company operates to the required standards?
Our company 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 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)