Ms Sarah Neary:

The National Standards Authority of Ireland, NSAI, recently revised standard recommendation No. 21 which deals with underground granular fill used beneath concrete floors in houses. That recommendation provides a great deal of detail on the physical and chemical performances of hard core and a grading structure for it. The material is well specified. An example specification is provided in Annex E of that standard recommendation, which is available to all designers and builders, in regard to the procurement and use of underground floor bearing slabs.