So me and my dad are renovating and decided to add electric radiant heating in out living room/kitchen. We are following this video as a guide https://youtu.be/sXhT1fYVPps. They said to use latex modified thinset above the wires. My dad bought unmodified thinset by accident. We were wondering if it was alright to use the unmodified stuff. If it is not a good idea to use unmodified thinset, what would be a good brand of latex modified thinset to use because they don't recommend one in the video.
The help is much appreciated.