The substrate must be ready for installation, dry, clean and structurally load bearing. If installation occurs on shrinking substrates frequent expansion joints should be included in the layout. Prime absorbent substrates in interior areas with Okatmos® DSG, Okamul GG or Okatmos® UG 30. Allow a drying time of at least 24 hours over calcium sulfate screed. For layers thicker than 5 mm on calcium sulfate screed, prime with Okatmos® DSG, Okapox GF and level indents with Servoflex-Trio-SuperTec. The maximum layer thickness on mastic screed is 1/4" (5 mm). Prime non-absorbent substrates with Okatmos UG 30. In exterior areas apply a contact layer of adhesive mortar and let it set.