House painting step by step
Painting a wooden house exterior is Finland's most common summer project — and the most demanding. A full house takes 3–7 days, requires careful planning, and depends on the right weather conditions. A well-done paint job lasts 8–15 years; a poorly prepared one starts peeling in two.
This guide walks you through the entire project step by step: from condition assessment to preparation, primer, topcoat, and final checks.
Project planning
Don't start painting on a whim. A successful house painting project requires planning weeks, sometimes months ahead.
Schedule
The best painting season is June–August, when overnight temperatures typically stay above the threshold. Wood requires a minimum of +5 °C, below 80% humidity, and 24 hours rain-free after application. Allow 3–7 working days depending on house size — plus 1–2 buffer days for bad weather.
Cost estimate
Professional exterior painting typically costs €20–40/m², or roughly €3,000–15,000 for a detached house. DIY material costs run around €1,000 — paint, primer, tape, protective covers, and tools. The labour portion qualifies for the household deduction (kotitalousvähennys), up to €1,600 per person or €3,200 for a couple.
Calculating paint quantity
Calculate the paintable area wall by wall, subtracting windows and doors. Common wood house paints cover 4–10 m²/l depending on surface roughness: sawn timber absorbs more (4–6 m²/l), planed panel less (8–10 m²/l). Plan for two coats plus a 10% waste margin.
Step 1: Condition assessment
Walk around the house and assess each wall separately. Look for:
- Peeling or loose paint — a sign of moisture problems or the old paint reaching end of life
- Cracks and rot — must be repaired before painting, especially below windows and at the foundation line
- Mould and algae — dark or green patches require treatment with mould wash
- Greyed wood — UV-damaged surface needs sanding but is not structural damage
Identify the old paint type: bend a paint chip — if it flexes, it's water-based; if it snaps, it's oil-based. The new paint should be the same type or a transition product (e.g. alkyd-acrylic).
Step 2: Washing
Wash all walls top to bottom with a garden hose or low-pressure washer. Don't use a high-pressure washer up close — it damages the wood. If the surface has mould or algae, treat with mould wash first and let it work per the manufacturer's instructions.
Let the surface dry for at least 1–2 days after washing. Wood moisture content should be below 15% before painting. A moisture meter is an inexpensive investment that prevents costly mistakes.
Step 3: Scraping and sanding
Remove all peeling and loose paint with a scraper. If the paint is in good condition and well-adhered, light sanding is enough to ensure adhesion for the new coat. Sand the surface to a rough finish with 80–120 grit sandpaper, by hand or machine.
Fill cracks and holes with exterior-grade wood filler. Let it dry and sand smooth.
Step 4: Masking and protection
Protect windows, doors, sills, foundations, decks, and outdoor furniture with painter's tape and plastic sheeting. Trim bushes and vegetation at least 10 cm from the wall. Lay drop cloths along the base of each wall.
Step 5: Priming
Bare wood always needs primer. Primer improves adhesion, evens out absorption, and protects the wood from moisture. Use a primer from the same product line as the topcoat. Apply with a brush following the wood grain.
Prime all bare spots and repaired areas. Intact old paint doesn't need primer — sanding alone is sufficient.
Step 6: Topcoating
Apply the topcoat in two coats. Choose a topcoat based on the surface and the existing paint system — for example, a water-based exterior wood paint (e.g. Tikkurila Vinha, Teknos NORDICA EKO, or Uula Pellavaöljymaali (linseed oil paint)). Let the first coat dry for the time specified by the manufacturer — typically 2–4 hours for water-based paints, 12–24 hours for oil-based.
Technique
- Start at the top and work downward
- Always paint in the direction of the wood grain
- Carry the paint from one end of the board to the other — don't leave wet edges mid-board
- Work in the shade: start in the morning on the wall the sun isn't hitting, and follow the shadow around the house
- Stop painting at least 2–3 hours before evening cooldown so the paint has time to dry
Around windows and trim
Paint large wall areas first with a roller or brush, then finish around windows, doors, and trim with a small detail brush. Casing and metal flashing are often different materials — check whether they need their own paint (e.g. metal paint).
Scaffolding vs. ladders
For a single-storey house, sturdy A-frame ladders are sufficient. For two storeys or more, scaffolding is always the safer and more efficient option. Scaffolding can be rented for the painting season — typically €200–600 per week depending on height.
- Scaffolding: stable working platform, efficient for large surfaces, reduces the risk of falls
- Ladders: suitable for small touch-ups and low areas, always require a second person to steady them
Most common mistakes
- Incomplete preparation — up to 60–70% of paint failures trace back to inadequate surface prep
- Painting in wrong conditions — too cold (<+5 °C), humid (>80%), or on a damp surface causes peeling within the first year
- Wrong paint type over old paint — oil over water-based or vice versa leads to poor adhesion
- Too thick a coat — causes runs, uneven drying, and wrinkling
- Second coat too soon — the previous coat must dry per the manufacturer's instructions
DIY vs. professional
Painting yourself saves 60–80% on labour costs, but demands time, physical fitness, and attention to detail. Hiring a professional makes sense when:
- The house has two storeys or more
- Walls have extensive rot or structural problems
- Old paint may contain lead (houses built before 1970)
- The schedule is tight and the weather window short
Remember that the labour cost qualifies for the household deduction — it significantly narrows the cost gap.
Weather monitoring
Wood surfaces require a minimum of +5 °C, below 80% humidity, and 24 hours rain-free after application. Wind should not exceed 8 m/s — strong wind dries the paint too quickly and creates an uneven finish.
Pay attention to overnight temperatures too: if the temperature drops below +5 °C at night, drying stalls and can cause problems. Check the forecast at least 24 hours ahead.
Checklist
- Condition assessed — rot repaired, mould treated
- Walls washed and dried 1–2 days
- Peeling paint scraped and surface sanded
- Old paint type identified
- Protection in place — windows, doors, foundations, ground
- Primer applied to bare areas
- Enough paint — area calculated, waste margin included
- Weather checked: +5 °C, <80% humidity, 24h rain-free, wind <8 m/s
- Painting started in the morning from the shaded side
- Second coat only after previous coat dried
Also read the guide Outdoor painting fundamentals — surface prep, manufacturer instructions, and weather planning are covered in detail. Painting in sunshine? See the guide Painting in sunshine.