HomeShield Dampstop Duo is a specially formulated premium quality acrylic primer with superior alkali, damp and efflorescence resistance properties both from positive and negative sides of the wall. It consists of penetrative polymer in combination with pore blocker which blocks the surface porosities of plastered wall/putty and hardens the surface to effectively counter the dampness both from the positive and negative side. Dampstop Duo also prevents alkali leaching/ efflorescence and enhances the durability of the topcoat paint system.