Exterior Maintenance · 9 min read · Intermediate

How to Paint Exterior Walls: Preparation, Repairs & Weather

Prepare masonry properly before painting and avoid trapping moisture or coating unstable render, brickwork or existing paint.

Key points & steps

Inspect the wall before decorating. Active leaks, failed gutters, persistent damp, blown render, significant cracks or friable masonry should be diagnosed and repaired before painting.
Check whether the existing surface is sound and compatible with the new coating. Remove loose or flaking paint rather than sealing it underneath another coat.
Clean dirt, algae and loose material using a method suitable for the substrate. Avoid excessively aggressive pressure washing on weak render, old pointing or soft masonry.
Repair local defects with materials compatible with the wall construction and allow repairs to cure or dry as required.
Mask and protect windows, doors, vents, paving and neighbouring surfaces from splashes and overspray.
Use primer, stabilising solution or a first-coat system only where the coating manufacturer recommends it; do not use stabiliser simply as a substitute for removing loose material.
Apply exterior masonry paint within the stated temperature and weather limits, avoiding rain, frost and strong direct heat where these conditions conflict with the product instructions.
Maintain safe access. Large elevations, difficult ground, work near roofs or unstable ladders are reasons to use suitable access equipment or a professional rather than stretching from a ladder.

Painting over a moisture problem can hide the symptom temporarily without solving the cause.
Older solid-wall or historic buildings may need vapour-permeable materials rather than a generic modern coating system.
Check the forecast for the full curing period, not just the hour you start painting.