| Sub-floors solid or wood need to be dry. British Standards state a
screed should be tested using Hygrometry as described in annex A in the
standards. The maximum level of relative humidity in the screed is 75%.
There are many manufacturers of moisture testing equipment such as
Tramex and Protimeter whose instruments can be used to identify areas
for further testing with a hygrometer. These instruments can also be
used to check the relative humidity to British Standards. The duration
of the test will depend on the sub-straight.|
Tiling onto a wooden floor is a big no no , because it can cause your new tiles to crack with the natural movement and expansion you get with wood, The following over boarding should be used to decouple the tiles from the movement ...
Taken from there website click here
Why HardieBacker®Only backer board with a lifetime warrantyUsed in place of regular drywall, gypsum boards, glass mesh cement boards, and "floated" walls/floorsBasic Composition: 90% Portland cement and sand with selected additives