Cavity Assessment Surveillance Scheme (CASS®)


For many years the British Board of Agrément has issued Agrément Certificates for cavity wall insulation and these, together with the related BBA Approved Installer Scheme, have provided high levels of assurance in respect of the some six million cavity wall insulation installations carried out over the past 20 years.

The BBA is continually looking to learn from experience and use those lessons to improve outcomes for the industry and consumers. With regards to the retrofitting of cavity wall insulation it is clear that, in some cases, consumer confidence is being undermined by the perception that insulation is being installed into properties which are unsuitable.

To seek improvement in this area and to increase consumer confidence, the BBA has developed a Cavity Assessor Surveillance Scheme (CASS®) covering Property Assessors. CASS® will check at the beginning of the process the suitability of properties proposed by Property Assessors for cavity wall insulation and it will provide independent third party validation of suitability.

The costs of providing this additional level of consumer reassurance will be borne by the industry, not by the consumer, with the BBA ensuring a seamless process. Having liaised with the industry, DECC and the Guarantee Providers, we know that the major stakeholders are fully supportive of CASS® and we are confident that, in many cases, a successful CASS® check will become a requirement for the issuing of guarantees.

For further information on CASS® and related matters, please telephone 01923 665321 or email

Lodging assessments on the CASS® platform

The videos below show how to lodge your cavity assessments onto the CASS® platform.

For Assessors

Disputes and Appeals

For company administrators

To look for an approved installer, use our search tool at the bottom of this page.

If you have any questions about our installer approval and inspection services, please get in touch with a member of the BBA team using the details on the Contact Us page.

We’ll help you find what you’re looking for…