IS:465

IS:465 is the Irish Standard used to evaluate homes impacted by defective blocks. However, the underlying cause and testing methods have been shown to be flawed. The standard is based on the mica freeze-thaw theory, which has been proven incorrect; the actual issue is Internal Sulphate Attack (ISA) caused by the presence of pyrrhotite. As a result, the testing and proposed remediation options are inadequate for repairing affected properties. IS:465 is currently under review, and this review must incorporate the latest research, necessitating updates to the remediation strategies. Consequently, a comprehensive revision of the Enhanced Defective Concrete Block Scheme will also be required.