Manchester Building & Testing Laboratories can determine moisture content of the screed and sub floor on site by testing the relative humidity in an insulated isolated pocket of air directly above the screed to BS 8203:2001+A1:2009. The Moisture content can also be determined by sealed samples which are then taken back to our laboratories.
Sub floor construction moisture , is a common problem which can affect the final floor finish , the rule of thumb is that it takes one month for each 25 mm of sub floor thickness.
Failure to ascertain the moisture content can adversely affect the final floor finish such as vinyl or Amtico etc., it can also adversely affect the application of a damp proof membrane ( DPM ) at very high readings.
According to BS 8203:2001+A1:2009 Experimental evidence has shown that when the measured relative humidity falls to 80 % the water has evaporated from the coarse pores and the screed is sufficiently dry to allow installation of resilient floor coverings. If some allowance is made for errors in determining the relative humidity, it is reasonable to recommend that the concrete be considered dry when the relative humidity falls to 75 % or less.