Floor Screed Moisture Level Testing
A digital hygrometer stuck to the floor for a minimum of 24 hours, confirms and accurately measures the moisture levels present in the subfloor. If the reading is below 75% RH (below 65% for wood flooring), then a resilient floor covering can be installed. (RH relative humidity, is a percentage measurement of the moisture vapour in the concrete slab).
If the reading is above this but lower than 92% RH, then it is advised that a single coat of a liquid DPM be applied. If however the subfloor reading is above 92% RH, then two coats of a liquid DPM is required for fully bonded floor coverings or an isolator membrane can be used in the same manner but also for floated materials.
Each coat of DPM would take around twenty four hours to dry under normal conditions. This can be speeded up with the use of an accelerator additive, to three hours per coat.