I'm building a double storey extension, would it be better (stronger, resistant to frost, better heated) to build the external walls using Celcon solar blocks (235mm thick) only or a cavity wall of brick and Celcon solar blocks (100mm thick), with Rockwool foam insulation in the cavity.
Looking in the forums I've notice some concern about Celcon blocks being prone to frost, how serious is this?
Looking in the forums I've notice some concern about Celcon blocks being prone to frost, how serious is this?