The invention relates to a knit fabric for orthopedic support material. The knit fabric comprises in the weft yarn in-lay/cross direction synthetic organic microdenier yarn of no greater than 1.5 denier per filament (dpf) and synthetic organic multi-filament yarn of greater than 2.5 denier per filament (dpf). It is impregnated with a curable resin which on activation with a curing agent forms a cast supporting the patient's limb. The knit fabric according to invention exhibits the high holding capacity of the resin over time, said capacity being sufficient to prevent resin leak from a resin-coated fabric.