Silicon water cures as does Silane based sealer so they would give a falsely low reading whereas decorators filler is water based so can lead to a false high. I've known people use plumbers mate or glaziers putty before both of which should be fine. As long as it does not use or give out water it should be ok. also bear in mind that digital hygrometers are affected by temperature. If its warm itll give a higher reading than if its is cold despite the screed having the same moisture content. this is to do with the way the hygrometer works. Carbide Bomb is not affected by temperature.
Yes indeed. The test is designed to be carried out at 20degrees C. I have generally found between about 18 and 22 sufficiently accurate. One of the issues I see with this test all the timeline people try and test with the underfloor heating switched on or the room is unheated and o oh 8 degrees especially this time of year. I prefer carbide bomb for speed and accuracy but of course it costs about 600 quid to buy one
