Bonding Primer has been specially designed to be used on uncoated surfaces or previously painted exterior masonry surfaces so that Silicate Masonry paint can be applied over the top. Unlike the original Silicate Primer which cannot form a bond with pre-painted surfaces, Bonding Primer provides a bond between a ‘sealed’ wall and the paint, allowing Silicate Masonry Paint to ‘stick’ to the pre painted surface. It is a extremely durable primer, helping the top coat of Silicate Masonry to last around 5- 6 years much like their other masonry paints. Bonding Primer by Earthborn dries to a White finish.