Self-leveling concrete (also called self-leveling underlayment or self-leveling mortar) can be purchased at most hardware and home center stores. Unlike the concrete used for sidewalks and other outdoor features, self-leveling concrete comes in the form of a fine powder and contains no aggregates such as sand or pebbles. There are self-leveling products that come “pre-mixed,” but these are not compatible with radiant floor products. Only use self-leveling concrete that is mixed onsite.
There are many high-quality brands available that can be used with radiant heat products. We do not recommend any one over the others.