SR 21 is a document listing the Irish Standard Recommendations on the use of the European Standard EN 13242. The document gives guidance on the best options to choose for specific engineering applications.

Annex E is a section of SR 21 which deals specifically with guidance on specifying aggregate properties for granular fill for use under concrete floors or footpaths.

In March of 2016 the NSAI published the revised draft of S.R. 21. From date of publication the Standard becomes the only specification that should be used for granular materials to be used under concrete floors and footpaths

SR 21: Guidance on the use of I.S. EN 13242:2013 – Aggregates for unbound and hydraulically bound materials for use in civil engineering work and road construction.

T.0 Struc

0-125mm Structural Layer for depths in excess 900mm

T.1 Struc

0/31.5mm (Crushed Rock) Structural Layer for depths less than 900mm

0/40mm (Crushed Gravel) Structural Layer for depths less than 900mm

T.2 Perm

4/40mm Gas Permeable Layer

T.3 Blind

0/4mm Blinding Layer

T.0 Struc Unbound Granular Fill material is recommended for use where the fill material will be subject to substantial loading and /or dynamic loading, or the depth of fill is greater than 900 mm to the top of the subsoil.

T.1 Struc 0/31.5 Unbound Granular Fill (Crushed Rock) or 0/40mm Gravel is recommended for use where the overall depth of fill to subsoil is less than 900mm.

T.2 Perm 4/40mm Gas Permeable Layer is recommended in any building where a Radon Sump is to be operational in the sub-floor including all occupied new build projects, i.e. anywhere a person might be for work, leisure or residence.

T.3 Blind 0/4mm Blinding Layer is used when blinding the top surface of the T.2 Permeable material to ensure the radon barrier is not punctured and there is a level surface upon which to place the insulation and pour the concrete.

Annex E materials are the only materials that should be specified for use under concrete floors and footpaths

It is the sole responsibility of the customer/site contractor to establish a system of traceability to ensure the correct material is used in the correct application.

IS 888 “Code of Practice for the procurement and use of unbound granular fill hardcore material for use under concrete floors” has also been published by the NSAI. This document covers all aspects of ordering, delivery, placement and traceability that may be required by the material user and specifier.