Sempatap A Primer is used to treat absorbent surfaces before the application of Sempatap Adhesive for Sempatap Thermal and Sempafloor. White in colour, the primer is water-based and can be applied to plywood, plasterboard, brick, wood and more. Sempatap A Primer needs to be stirred before use and then applied liberally with a brush or roller, avoiding pools of primer or uneven coats. The primer takes between 1 to 2 hours to dry and then you can continue to apply adhesive and the rest of the chosen Sempatap system. Sempatap A Primer Specification Tub Size: 5 Litres