Getting The Measure Of Floors & Walls
WITH more flooring contractors offering a floors and walls ‘package’ to customers, we are increasingly asked about the installation of hygienic PVCu wall finishes, and the maximum substrate moisture level before installing. There are many similarities between PVC floor and wall finishes, and their basic requirements are exactly the same. Walls substrates must be smooth, sound, dry and free of contamination.
As semi rigid PVCu wall cladding systems are traditionally fixed with either a two-part polyurethane adhesive or a single-part acrylic adhesive, working conditions on site should be exactly the same as for floor installations. One significant difference between the two, however, is how the substrate moisture level is measured before starting the installation. As we know, subfloors are measured in RH terms and generally should not exceed 75% RH when laying most types of floorcoverings.
For walls, the process is somewhat different. The accepted industry standard for measuring moisture in walls is with Protimeter Surveymaster equipment. The relative readings of an electrical moisture meter generally measure the free water in a material, therefore they closely indicate the relative dampness of many different materials. Although the Protimeter Surveymaster does not measure RH, its indications are a fairly close representation of it. It measures the surface moisture content in terms of % WME (wood moisture equivalent). There are several different types of wall substrate that semi rigid, hygienic PVCu wall cladding can be fixed to. These include fairfaced blockwork, brickwork, sand and cement render, plaster and most types of dry
When testing moisture content of any of these substrates on-site, the readings should not exceed 16% WME on the Protimeter. This ensures the adhesive is not compromised and the bond strength to the substrate
Mike Fielding is a member of the technical team at Altro
T: 01462 489405
This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.