Texrite 31465 500 Mortar Bed 50 lbs - Mortar Bed 500 is a blend of Portland cement and graded silica aggregates developed to produce a dense substrate on which to apply ceramic tile or stone. It is a factory controlled, consistent proportioned pre-blended mortar. Simply add water or Latex Bond Admix 150 liquid additive and mix to a smooth, easy to apply 1 1/4″ – 2″ thick mortar bed.