I find that with experience you will be able to feel as you lay tiles if they are embedded solid....it's hard to describe but you can tell as you are fixing whether the tile is well bedded......the pros will know what i mean though.....
And while you are spreading your adhesive bed, you can feel slight dips etc in the feel of the trowel so adjust the bed to suit....this feel as i call it will come with experience.....trust me....![]()
Does this apply to me,i had the supplier come out and look at the stuff and they gave me the powdered stuff as a replacement within a short time of laying the tiles they were solid
the tub stuff an impression of the back of the tile was clearly seen on the adhesive with no slack areas
Stephen