Pressure Washing Before Painting in Newcastle

Washing walls and render

Brick, cement render, and fibre cement walls: Use 1,500–2,000 PSI with a fan-tip nozzle, working top to bottom to avoid streaking. This pressure is strong enough to remove mould and algae from eaves and downpipe areas while remaining safe for most masonry surfaces.

For painted render: Keep the nozzle 20–30 centimetres away and use a sweeping motion rather than holding it on one spot, which chips existing coatings. This distance gives optimal cleaning power without damaging the paint layer.

Washing timber and weatherboard

Soft-wash mode (low pressure + cleaning solution): The safest approach for timber cladding. High pressure splinters fibres, forces water behind cladding, and damages putty in window frames — all of which compromise paint adhesion and cause future peeling.

Application process: Apply mould treatment solution, dwell for 10–15 minutes, then rinse with a wide fan nozzle at lowest pressure. Allow 48–72 hours drying in dry weather before sanding or priming, as timber absorbs significantly more water than masonry.

Washing concrete and driveways

High-pressure treatment for concrete: Driveways, paths, and retaining walls tolerate 3,000 PSI with a rotary nozzle for tough staining. This higher pressure effectively removes oil, grease, tyre marks, and mineral deposits that prevent paint or sealant adhesion.

Drying requirements: Concrete absorbs water deeply into the slab and requires extended drying time before painting. Test with a moisture meter (readings below 5% are safe) or tape plastic to the surface for 24 hours — moisture collection underneath indicates the slab needs more time.

Recommended wait times before painting

Painting onto a damp surface is one of the most common causes of peeling. Use these guides as minimums — add extra time in humid weather or overcast conditions.

How to check if surfaces are dry enough

A moisture meter is the most reliable check — readings below 15% for timber and below 5% for masonry are generally safe for priming. Without a meter, the palm test works as a quick check: press your palm firmly against the surface and hold for 10 seconds. If it feels cool or damp, wait longer.

For concrete, tape a clear plastic sheet (about 30 cm square) flat to the surface. Check after 24 hours — if moisture has collected underneath, the slab is still releasing water and is not ready for coating.

Local example — Merewether coastal wash

A recent Merewether project required soft-wash treatment on north and east elevations before an exterior repaint. Salt and mould had built up under eaves and in sheltered corners. After washing, we allowed 48 hours of drying before sanding and priming. The coatings bonded well, and the client noted a visible difference in finish smoothness compared to their previous repaint which had skipped the wash step.