Pressure Washing Before Painting in Newcastle

Washing walls and render

Brick, cement render, and fibre cement walls handle standard pressure washing well. Use a fan-tip nozzle at 1,500 to 2,000 PSI and work from top to bottom to avoid streaking. Pay extra attention to areas under eaves and around downpipes where mould and algae collect.

For painted render, avoid holding the nozzle too close to one spot — this can chip existing coatings. A consistent sweeping motion at 20 to 30 centimetres from the surface gives the best balance of cleaning power and surface safety.

Washing timber and weatherboard

Timber surfaces need a gentler approach. Soft-wash mode — which uses lower pressure combined with a cleaning solution — is the safest choice. High pressure can splinter timber fibres, force water behind cladding, and damage putty in window frames.

Apply a mould treatment if needed, let it dwell for 10 to 15 minutes, then rinse with a wide fan nozzle. Timber absorbs more water than rendered surfaces, so allow at least 48 to 72 hours of drying time in dry weather before sanding or priming.

Washing concrete and driveways

Concrete driveways, paths, and retaining walls can take higher pressure — up to 3,000 PSI with a rotary nozzle for tough staining. If you plan to paint or seal concrete, make sure all oil, grease, and tyre marks are treated with a degreaser before pressure washing.

After washing, concrete needs ample drying time because it absorbs water deep into the slab. Test with a moisture meter or tape a plastic sheet to the surface for 24 hours — if moisture collects on the underside, 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.