b'ASK THE EXPERTSAsk the Experts Q&As are culled from member inquiries to NTCAs Technical Support staff. To become a member and make use of personal, targeted answers from Technical Support staff to your installation questions, contact Jim Olson at jim@tile-assn.com.QUESTION each method it notes that they are Good morning. Im writing withappropriatelyusedinResidential aquestionthatIhopeyoucan1orCommercial1typeinstal-eitheranswerorpointmetothelations.Commercial1areasare best resource that would be able todescribedintheEnvironmental provide some insight. Exposure Classifi cation of the TCNA WeredoingarchitecturalworkHandbook as tile surfaces that will for a national chain restaurant andnot be exposed to moisture except Id like to confi rm that were usingforcleaningandgivesexamples theappropriatebackerboardforsuchas:fl inareaswithnooors tilewalls.Thequestionis:mois- directaccesstotheoutdoorsand ture-resistant gyp-board or cementnowetutilityfunctions;hallways; board? dry area ceilings; soffi ts, decorative/Weusewalltileinfoodprepaccent walls; and corridor walls.areasandrestrooms.ThewallsCommercial2isdescribedas getwipeddownandmightgetsurfacesthataresubjecttomois-splashed with water, but they dontture but do not get soaked or satu-get hosed down or soaked. rated due to system design or time Let me know if theres a simpleexposure. Examples of Commercial rulewhencementboardshould2 installations are: fl in bath- oors be used, as opposed to moisture- roomsandlockerrooms;some resistant gyp, or if theres a referencebacksplashes and other walls such standardthatwouldshedsomeasbathroomwallsandwainscot lightonthisquestion(Ialreadywhere water exposure is limited and tried the TCNA Handbook). or water is removed. Commercial 3isdescribedasareasthatare ANSWER soaked, saturated, or regularly and Thankyouforcontactingfrequently subjected to moisture or theNationalTileContractorsliquids. It also lists some commer-Association.Industry-recognizedcial kitchen walls.wall tile installations are found inMethodW244usescement the TCNA Handbook.backerboardintheinstallation Twomethodsthatusegyp- and is suitable for Commercial 1,2, sumboardaremethodW242and 5 installation. andW243.IntheEnvironmental Robb Roderick, ExposureClassifi cationsectionofNTCA Technical Trainer26 TileLetter | April 2020'