Navigating non-pigmented options and moisture concerns

QUESTION

I am working on a fireplace surround and am using cement tiles. The thorough instructions ask for a nonpigmented grout. I have spoken to the clients and impressed upon them the need for a mockup for the grout. They agreed. 

 I was wondering if the technical team has any recommendations, insights or referrals for an unpigmented grout. The instructions are very careful to not make recommendations, and put the responsibility on the installer and the grout manufacturer. I have already boxed all the colors and sealed the tiles once. 

ANSWER

Thank you for reaching out to the NTCA Technical Team with your question about cement tile and non-pigmented grout.

As you probably know, although cement tiles provide a very distinct and desirable look to some, they have their challenges during the installation and grouting process. After talking with a few people this morning about your question it sounds like a single-component grout from your manufacturer of choice is going to be the best option. I would reach out to your preferred grout manufacturer and confirm this with them. 

I am thrilled to hear you are providing the homeowner with a mock-up prior to installation. This is always a best practice for any tile installation. 

Talking with several people this morning about your question, the same concern continued to come up over and over again: “moisture in the cement tile.”  Because of how cement tiles are made – and the fact that there is no industry standard for the manufacturing of cement tile – there can be a high moisture content in the cement tile at the time of installation. This can affect the thinset curing process. It could cause the sealer to appear cloudy, it could also affect the grout drying/curing properly, and may cause different shading in the grout
to appear. 

It would be a best practice to contact the sealer and grout manufacturer and find out their recommendation for moisture content percentage before applying the next coat of sealer. You may need to lay out the tile in a room with airflow for a period of time to reach this recommended moisture percentage.