Exterior Painting: How to Paint a House Outside in the UK
Quick Answer: Painting a house exterior in the UK typically takes 3-7 days and costs £800-£3,500 for an average semi-detached property. The process involves power washing, repairing render/masonry, priming, and applying 2 coats of quality masonry paint. Best results come from painting between May-September when temperatures stay above 10°C. Expect to pay £25-45/m² for professional work, or £300-600 for DIY materials alone. Why Exterior Painting Matters for UK Properties Your home’s exterior paintwork does far more than just look nice. It’s the first line of defence against British weather — driving rain, winter frost, summer UV, and everything in between. Most UK properties need repainting every 5-10 years depending on exposure, paint quality, and substrate type. South-facing walls and exposed coastal properties deteriorate faster due to increased UV and salt exposure. Beyond aesthetics, proper exterior painting: Protects render and masonry from water penetration Prevents freeze-thaw damage during winter months Reduces heat loss through micro-cracks (improving thermal efficiency) Increases property value by 2-5% according to estate agents Stops biological growth (algae, lichen, moss) on north-facing walls Skip maintenance too long and you’ll face render repairs costing £40-90/m² rather than a simple repaint at £25-45/m². We see this constantly — penny-wise homeowners end up needing full render replacement because they ignored peeling paint for years. Understanding UK Masonry Paint Types Not all exterior paints are created equal. UK conditions demand specific formulations that handle moisture movement and temperature fluctuations. Paint Type Coverage (m²/L) Coats Required Lifespan Cost per 10L Standard Masonry Paint 6-8 2 5-7 years £30-50 Textured/Stipple Masonry 4-6 2 7-10 years £40-70 Premium Silicone-Enhanced 7-9 2 10-15 years £80-120 Masonry Stabilising Solution 4-5 1 N/A (primer) £35-55 Smooth vs Textured Masonry Paint Smooth masonry paint provides a clean, modern finish but shows every imperfection. You’ll need pristine render underneath — any cracks, hollows, or patches will telegraph through. Textured masonry paint (also called stipple or roughcast paint) hides minor surface irregularities and provides better weather protection through its thicker film build. It’s the go-to for older properties with less-than-perfect render. Popular UK brands include Dulux Weathershield, Sandtex Ultra Smooth, Crown Breatheasy Masonry, and Johnstone’s Stormshield. We’ve had excellent results with Dulux Trade Weathershield for its durability and colour retention — it’s worth the extra £20-30 per tin over budget alternatives. Planning Your Exterior Painting Project Proper planning prevents poor performance. Here’s what you need to consider before buying a single brush. Timing and Weather Windows Exterior painting in the UK requires a precise weather window. According to Building Regulations guidance on external works, ideal conditions are: Temperature: 10-25°C during application and drying (minimum 8°C overnight) Humidity: Below 80% relative humidity Wind: Less than 15mph (stronger winds cause flash drying and poor adhesion) Rain forecast: No rain for 24 hours after application (48 hours ideally) Dew point: Wall temperature must be 3°C above dew point to prevent condensation forming on fresh paint In practice, this means May through September are your best months. April and October are borderline — you might get lucky, but equally you might waste materials on paint that washes off in an unexpected shower. ⚠️ Warning: Never paint exterior walls in direct strong sunlight or when surface temperature exceeds 30°C. The paint will skin over before properly bonding, leading to premature failure. Early morning or late afternoon application works best. Calculating Paint Quantities Most homeowners underestimate how much paint they need. Here’s the professional approach: Measure each wall (length × height in metres) Subtract windows and doors (approximate 15-20% for typical semi-detached) Add 10% wastage factor for cutting in, spillage, and absorption Divide by coverage rate (typically 6-8 m²/L for first coat, 7-9 m²/L for second coat on sealed surfaces) Example for a typical UK semi-detached house: Total wall area: 180m² (minus windows/doors = 145m²) With 10% wastage: 160m² First coat at 6m²/L: 27 litres required Second coat at 8m²/L: 20 litres required Total: 47 litres (buy five 10L tins) Budget brands from B&Q or Wickes cost £30-40 per 10L tin. Trade-quality paint from Travis Perkins or Brewers Decorator Centres runs £50-75 per 10L. Surface Preparation: The Make-or-Break Stage Professional decorators spend 60-70% of project time on preparation. It’s not glamorous, but it’s where quality work separates from cowboy jobs. Power Washing and Cleaning Start with a thorough pressure wash at 100-150 bar (1500-2200 PSI). Higher pressure damages render — we see gouged surfaces regularly from DIYers hiring commercial-grade machines. Rent a domestic pressure washer from HSS Hire or Jewson for £35-50/day. Focus on: Removing all loose paint, dirt, organic growth, and efflorescence Working from top to bottom to avoid re-soiling cleaned areas Keeping the lance 300-450mm from the surface Allowing 48-72 hours drying time before painting For biological growth (green algae, black mould, lichen), apply a fungicidal wash like Dulux Weathershield Multi-Surface Fungicidal Wash (£15-20 per 5L). Brush or spray onto dry walls, leave for 24 hours, then rinse thoroughly. Repairing Render and Masonry Any cracks wider than 2mm need filling. Hairline cracks below 2mm can usually be bridged by quality masonry paint, but wider defects will reappear within months. For sand-cement render repairs, mix 5:1 sharp sand to cement with a waterproofer added. Our detailed guide on sand and cement render mix ratios covers the specifics, but key points are: Rake out cracks to at least 20mm depth using a plugging chisel Brush out dust and debris, then dampen with water Apply PVA bonding agent (5:1 water dilution) to edges Press mortar firmly into crack, building up in layers if deep Texture to match surrounding render using a damp sponge or stipple brush Allow 7-14 days curing before painting For small patches (less than 50mm), ready-mixed exterior filler like Polyfilla Exterior Filler (£6-8 per tub) saves mixing mortar. Just ensure you get exterior-grade filler — interior products disintegrate within weeks outdoors. Pro Tip: For blown render (sounds hollow when tapped), don’t just paint over it hoping for the best. Hack off the loose section back to sound material, then patch properly. Paint won’t fix
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