Pyrite and mica are two forms of naturally occurring minerals found in stone that can result in damage to building components when in service. We’ve investigated over 500 cases of buildings damaged by pyrite within the gravel beneath floor slabs. In recent years we’ve found its damaging effects in the block walls of houses and in roof slates. This type of damage is easily mis-diagnosed as subsidence damage. We know the difference. We are a member of the ‘Pyrite (Building Condition Assessment) Register’ of Engineers Ireland.