AS 2455.2:2019 Textile foor coverings — Installation practice
Refer to the written instructions of the manufacturer of the textile floor covering and other components of the total floor covering assembly (e.g. screed topping/levelling compound, underlay, installation adhesive) to fill out the allowable moisture content (RH %) and alkalinity (pH) limits for their products. Where manufacturer’s instructions are not available, the mandatory default RH and pH limits contained in Clause B.5 should be used.
As part of a risk minimization approach, testing subfloor moisture content (RH %) and alkalinity (pH) as a survey of the floor area, is recommended. The results of this survey will provide an indicative measure of the RH % and pH content of the subfloor at the time of testing. It cannot be taken that a concrete moisture or alkalinity issue may not occur at a later date due to unforeseen circumstances.
For indicative results, a minimum of four moisture content (RH %) and alkalinity (pH) tests for any project and not less than one test per 500 m 2 of floor area is advisable.
If following this indicative testing there are still concerns about the subfloor conditions, or the results are close to the manufacturer’s specified moisture content (RH %) and alkalinity (pH) limit, then for a more definitive survey the number of tests should be increased to one moisture content (RH %) and alkalinity (pH) test point for each 100 m 2 .
NOTE 1  Moisture content (RH %) and alkalinity (pH) testing is generally not required when conventionally backed textile floor coverings in roll form that allows water vapour to pass through the carpet structure and vent into the atmosphere, is installed on a concrete subfloor using the carpet gripper method. Refer to textile floor covering and other floor materials manufacturer’s instructions.
NOTE 2  For other types of textile floor covering installations, including direct stick, dual bond and low adhesive carpet tile “connectors” (e.g. polyester/plastic squares with adhesive on one side and double-sided adhesive squares and pressure sensitive adhesive dots), it is the responsibility of the building owner or head contractor to have the slab tested by a competent person and give the results in the form of a written report to the flooring contractor.