The type of primer depends on the type of substrate. Brittle substrates need to be reinforced with ALPOL AG 700 deep-penetrating primer. In case of plasters applied on concrete substrates, it is recommended to use ALPOL AG 702 primer that forms a bonding coat for gypsum plaster, whereas for absorptive substrates (walls made of silicates, cellular concrete, bricks and ceramic blocks), the primer of choice is ALPOL AG 703. The substrate should be treated with primer at least 24 hours before plastering.
Such surface is to be primed with ALPOL AG 703 primer for absorbing substrates. Before plastering, it is essential that the substrate be primed first. Concrete substrates are covered with ALPOL AG702 primer applied 24 hours before plastering.