The growth of silicalite zeolite layers by in situ crystallization on zircon porous supports has been investigated. Because of lower solubility in the mother liquor with respect to alumina substrates, zeolite weight gain with time is enhanced. Using the batch formulation 4.1 Na2O:50 SiO2:691 H2O:TPABr it was not possible to grow zeolite layers in an oriented fashion in the temperature range of 140 degrees-180 degrees C. It was observed that, unlike alumina substrates, porous zircon supports have a high affinity for oriented deposition of silicalite seeds (highly oriented 200/020 planes) by the dip-coating process. This phenomenon is a strong function of slip pH and concentration. Seed layers are prone to heavy mass losses during the hydrothermal process. A "fixation" process has been applied for the first time to fix the latter by reacting surface Zr-OH and Si-OH groups by condensation reactions between the support and the seed and among the seeds themselves. Such a fixed seed layer undergoes mostly crystal growth with minimal nucleation during the hydrothermal step, resulting in a dense highly oriented zeolite layer.