Hi ATS,
This has been a recent topic, so it might be useful to read this TTA article, scroll down to
section 3:5 Moisture Sensitivity.
http://www.armatilearchitectural.com/DatabaseDocs/dwn_756473418_tilingwithresinagglomeratedtiles.pdf
hope this helps
I've just read the pertinent parts of that document and it's misleading. I'll expand. Here is the section that deals with water absorption:-
3.4 Characteristics/performanceBecause the products consist predominantly of natural materials, they haveperformance characteristics similar to natural stone.Granite and quartz agglomerated tiles are harder wearing than those made withmarble. The particular performance and suitability in locations should be confirmedwith the manufacturer. Granite and quartz agglomerated tiles are more resistant to acidic chemicals thanmarble agglomerated composite tiles.
3.5 Moisture sensitivityResin agglomerated tiles may show varying degrees of moisture sensitivity and thischaracteristic is exhibited by curling caused by differential expansion.For this reason, it is essential that any cementitious floor screeds to receive resinagglomerated tiles should be completely cured and tested to ensure that they have amoisture content of not more than 2% by weight or 75% relative humidity using theappropriate test equipment and also that an appropriate adhesive is chosen. Seeclause 4.3 Resin agglomerated tiles are not recommended for use in external areas orswimming pools or any other water retaining structures, e.g. spa baths or fountains.Resin agglomerated tiles can be used externally on facades by utilising mechanicalfixing.
The problem with the above statement is they've grouped three very different materials into one statement, granite, marble and quartz agglomerate.
Each of these products has different absorption rates determined by the material from which they are produced.
Both Granite and marble are porous, to varying degrees due to their structure, quartz crystals aren't.
The average porosity of quartz slab I was involved in manufacturing was 0.04% by weight. i.e it really didn't absorb much at all if anything. Silestone state that 0.04% is their average absorption rate.
So I don't see how a product with such a low absorption rate can be materially effected by moisture absorption.
Granite and marble agglomerates yes, that makes sense due the natural stone's content ability to absorb. But quartz? I just don't see it.