Masonry Preparation: Repairs, Stabilising & Waterproofing

Perform the "Thumb Test." Rub your palm or thumb firmly across the existing painted surface. If your hand comes away white or powdery, the surface is "chalking." You must wash it down and apply a Stabilising Solution to bind the loose particles before painting.

This depends on the severity of the problem.

• Solvent-Based (High Performance): Required for very chalky, old, or highly porous surfaces. The solvent particles are smaller and penetrate deeper to lock the surface together.
• Water-Based (Eco-Friendly): Suitable for slightly dusty surfaces or newer render that just needs a light seal.

On bare, sound render, a "mist coat" (diluted paint) is often fine. However, on chalky or flaking surfaces, diluted paint is not enough. You need the specific binding resins found in a Stabilising Solution to glue the surface back together.

No. Paint is a thin coating, not a filler. Even if the paint bridges the crack initially, it will snap open as soon as the weather changes. You should fill hairline cracks with a flexible exterior acrylic filler or use a "High Build" reinforced coating designed to bridge small fissures.

"Blown" render means the render has detached from the brickwork behind it, leaving a hollow air pocket. You can find it by tapping the wall with a hammer handle; it will sound hollow compared to the solid "thud" of good render. These areas must be hacked off and patched, or they will eventually fall off.

Never use standard silicone sealant on areas you intend to paint. Paint will not stick to silicone (it repels it), leaving you with an ugly unpainted stripe. Always use a "Paintable" external filler or polyurethane sealant.

A high-quality Silane/Siloxane impregnator should dry clear and invisible (matte). It soaks into the brick rather than sitting on top like a varnish. However, cheaper "varnish-style" sealers can leave a "wet look" or sheen, so always check the label or do a patch test.

Generally, no. Water repellents are designed to repel liquids—including liquid paint. If you seal your wall now, you may not be able to paint it for 5-10 years until the sealer wears off. Decide if you want a natural look (Clear Sealer) or a coloured look (Masonry Paint) before you start.

Rising Damp comes from the ground up (usually stopping at 1 meter high) due to a failed damp proof course. Penetrating Damp can happen anywhere on the wall (even high up) and is caused by rain soaking through porous brick or cracks. Our sealers are designed to stop Penetrating Damp.