Flooring and Carpeting/ditra underlayment


Perry, I have have never used ditra for a tile underlayment before. I read on one of your answers you use modified motar to set the tile. Which i would also like to do. I know schluter recommends unmodified because of the curing factor being so much shorter than modified mortar, but the porcelain manufactures recommend modified for good adhesion. Here is my question: How long do you generally have to wait for the mortar to cure before you grout? I've seen answers from 2 weeks to 8 weeks! And what modified mortar do you recommend? THANKS FOR YOU HELP!

Thank you for your question Eric,

    My personal installation methods have sometimes contradicted recommended methods by Manufacturers mainly to satisfy my personal confidence in something that I am going to be responsible for over a set period of time. So my employing a Latex modified thinset for both sides of a tile install, in particular a Porcelain install...is my choice knowing and experiencing the outcome that has been successful in the past. It is how all of us installers have reached the point where we are...either after a few months or a few decades like me. When the ideal scenario presents itself and I have the luxury of time I will strive for 48 hours on the Ditra install, then depending on the format of the tile installed (size) I will allow more time for the larger format, typically 72 hours for the tile "over" the Ditra to cure before grouting. On most installs there are other areas or materials involved in the overall contract that I can attend to while the areas of concern cure to the desired time...follow me? Then I can confidently return and finish the install. Certainly the larger format installs 18" or 20" and larger do indeed take longer time for an overall cure time but that would also be true with a standard thinset, and as long as we are not talking about a Commercial application there is unlikely to be any problems with the timeframe that I work with. Porcelain tile is a special material that requires the more performance oriented setting material and I only use a white modified thinset and that being Mapei products. Some people confuse the "dry rate" with the "cure rate" both being different for different reasons. In new Construction with the pace of some current Builders schedules the foundation is still curing well after the people have moved in...it's just the way it is. Ok Eric I hope this helps you with your project, feel free to return anytime...

Perry V.

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Perry Vellenga


Ceramic Tile/Marble. I can answer questions about floor preparation, tile selection, layout questions, performance of products, expectations of finish, compatabilities, questions about grout and epoxies, evaluating an installer, asking the right questions to check competence...more? 33 years this August 2012/ many years in commercial application from exterior finishes to Mall store fronts/ interior finishes like floor packages in stores inside Malls examples: The Limited, Lerner/NY, Lane Bryants, Bombay Co., Now involved in Residential new construction covering all types of interior finishes and designs.


I worked in an exclusive field of floorcovering called "Tenant Development" which is by invitational bid only, by way of a National bid list. These are large floor packages usually over 3500 sq. ft. of 18" x 18" Marble and Granite and many other types of Marble and sizes. They are specialty stores where the floor package can cost upwards of $50,000 for one store. I have also done "Structure" stores and J. Riggins stores, Lane Bryant,Express and Body Shop stores where wood flooring is used. Presently work for a National Flooring Company in the Residential new construction arena that covers most interior design elements..Granite Slab tops/wood flooring both job finished and prefinished ect..

My response's are published all across the Internet and picked up by multiple Interior Design sites and Industry related web sites where people have questions...

too many most of which don't count...

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