The BBA Certifies a number of materials for a variety of applications and a properly designed and specified job, correctly executed, should not be a problem. However we cannot comment on individual cases, and it is recognised that quality of workmanship is an important aspect of a successful installation, as well as design and product selection. If the householder in question wants an assessment of their property, they should contact a Building Surveyor with expertise in the subject; suitable Building Surveyors can be recommended by RICS. Click here to visit their site.