When working with GRP fibreglass, resin must be stippled into the matting, not brushed on like paint.
Brushing spreads resin across the surface but can trap air and leave fibres dry. Stippling uses a tapping motion to drive resin deep into the fibreglass, remove air pockets and properly consolidate the laminate — especially around trims, corners and roof details where rollers can’t reach.
Standard decorating brushes and rollers are not suitable for this process. Their softer bristles are designed for paint and quickly break down when exposed to polyester resin and acetone. They also lack the stiffness needed to properly work resin into the fibreglass.
Using proper GRP application brushes and rollers ensures full wet-out of the laminate, reduces the risk of pinholes and helps achieve a strong, long-lasting roof finish.