Concrete Surface Moisture Levels

Concrete Moisture Levels
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Things have just become much easier for contractors installing carpet tiles on new concrete floors. Godfrey Hirst’s carpet backing technology has raised the bar, with our tiles now performing at higher surface Rh and pH levels without the use of a moisture barrier. Following stringent testing with the CSIRO, we will now fully guarantee our tiles at a surface moisture level above that currently prescribed by Australian Standard AS/NZS 2455:2007, being 70% Rh. This testing confirmed that our tiles, with Enviro Bac® backing technology, have a Moisture Vapour Emission Rate (MVER) similar to concrete. This allows the concrete to dry naturally unlike PVC and other backing types which have an MVER of 0 (totally impervious). Subject to the guidelines below, Godfrey Hirst now guarantees its tiles at up to 80% Rh and a pH level of 12. Across the industry there has been a lot of confusion in regard to the moisture level thresholds required for carpet tile installation. In order to help builders and contractors clarify these thresholds please refer to the following guidelines:

  • When installing any of Godfrey Hirst carpet tile, testing for subfloor moisture levels need only be carried out in accordance with the current Australian Standard AS/NZ 2455.2007 parts 1 and 2.
  • Godfrey Hirst recommends the use of the ‘hood method’ for RH testing in accordance with AS/NZ 2455.2007 parts 1 and 2 (Note: The ASTM F 2170 ‘in situ probe method’ is a US test method and is not in accordance with the current Australian Standard).
  • The current Australian Standard states 70% Rh as the highest surface moisture level recommended, however Godfrey Hirst will fully guarantee the performance of our carpet tiles when tested as up to an RH level of 80% and a pH level of 12 without the use of a moisture barrier provided Green Solutions GS - 444 pressure sensitive adhesive (manufactured and distributed by RLA Polymers) or Holdfast 410 solvent free pressure sensitive adhesive are used at surface moisture levels above 70%Rh.
  • If the RH level exceeds 80% or the pH level exceeds 12 please contact your local Godfrey Hirst commercial representative prior to commencement of the installation.

For further information about sub floor moisture levels or any of your carpet needs please contact us.

  Subfloor Moisture Testing of Godfrey Hirst Tiles by CSIRO