Why I Wrote This Guide (And Why Your Exterior Deserves Better)

Let me tell you about a house I saw in Cromwell last summer.

Beautiful 1990s weatherboard home. Great street presence. The owner had painted it himself five years earlier – watched some YouTube videos, grabbed the cheapest paint from the hardware store, and knocked it out over a long weekend.

Five years later? The north-facing wall looked like it had been through a war. Paint peeling in sheets. Bare timber showing through. The south side had mould creeping up from the foundation. And the window frames? Don't get me started on the window frames.

The fix? A complete strip back to bare timber, treatment for UV damage, new primer system, two full coats of quality paint. His "$800 DIY job" turned into a $14,000 professional restoration.

Here's the thing: New Zealand's climate doesn't forgive shortcuts on exterior painting. Our UV is brutal. Our temperature swings are mental. And depending where you are, you're dealing with salt spray, alpine frosts, or humidity that'd make a Queenslander blush.

After 14 years painting exteriors across Central Otago – from lakeside baches in Wanaka to high-country stations near Tarras – I've learned what actually works, what fails spectacularly, and what'll have you repainting in three years instead of fifteen.

This guide is everything I wish homeowners knew before they started. Whether you're DIYing or hiring a pro, this will save you thousands and years of frustration.

Part 1: Understanding New Zealand's Climate Challenge

Before we talk about paint, we need to talk about what your house is actually fighting against. Because our conditions are genuinely different from the rest of the world.

The UV Problem (It's Worse Than You Think)

New Zealand has some of the highest UV levels on the planet. In summer, our UV index regularly hits 12-13 – the same as the equator. In Central Otago, at 300-400 metres elevation, it's even more intense.

What UV does to paint:

• Breaks down the resin binders that hold paint together
• Causes chalking (that powdery surface when you rub the paint)
• Fades colours – especially reds, yellows, and blues
• Makes paint brittle and prone to cracking
• Accelerates the entire degradation process

That "15-year paint" from the hardware store? In Central Otago's UV, you might get 7-8 years if you're lucky. On a north-facing wall? Maybe 5.

The Temperature Swing Factor

Here's something that catches people off guard: the expansion and contraction cycle.

I've measured temperature swings of 45°C on a single wall in one day in Cromwell. Morning frost at -5°C, afternoon sun hitting 40°C on a dark-coloured wall. That's not unusual – that's just Tuesday in Central Otago.

What this does to paint:

• Constant expansion and contraction stresses paint films
• Creates micro-cracks that let moisture in
• Causes adhesion failure at edges and joints
• Makes flexibility crucial (cheap paint is often too rigid)

This is why paint systems designed for stable European climates often fail here. They're simply not flexible enough.

Regional Climate Variations

Coastal Areas (Auckland, Wellington, Tauranga coastline):

• Salt spray is the enemy – corrodes surfaces, undermines adhesion
• Higher humidity means slower drying and more moisture issues
• Milder temperatures but more frequent rain
• Mould and mildew thrive in these conditions

Central Otago (Queenstown, Wanaka, Alexandra, Cromwell):

• Extreme UV at altitude
• Massive temperature swings (daily and seasonal)
• Very dry air in winter (paint can cure too fast)
• Frost and ice pushing under paint edges
• Nor'westers bringing sudden hot, dry conditions

Southern Regions (Dunedin, Invercargill, Southland):

• Salt spray on coastal properties
• High rainfall and persistent dampness
• Cool temperatures slow drying times
• Moss and lichen love these conditions

North Island Interior (Hamilton, Rotorua, Taupo):

• Geothermal areas have unique sulphur issues
• High humidity in many areas
• Generally milder but still significant UV

Your approach needs to match your region. What works in Queenstown won't necessarily work in Auckland, and vice versa.

Part 2: Choosing the Right Paint System

This is where most DIYers go wrong. They think about colour and forget that paint is primarily a protective system.

Understanding Paint Types

Acrylic (Water-Based) Paints

The modern standard for exterior work. Quality acrylics have come a long way.

Pros:

• Excellent flexibility (crucial for our temperature swings)
• Good UV resistance in premium formulations
• Breathable – allows moisture to escape from timber
• Easy cleanup, low odour
• Quick drying in good conditions

Cons:

• Can't apply in cold temperatures (below 10°C)
• Sensitive to rain within first 24-48 hours
• Not all acrylics are equal – huge quality variation

Best for: Most exterior applications in NZ. Weatherboards, plaster, fibre cement, brick.

Alkyd (Oil-Based) Paints

The old-school option. Still has its place but increasingly niche.

Pros:

• Superior adhesion to difficult surfaces
• Self-levelling (fewer brush marks)
• Can apply in cooler temperatures
• Excellent for high-wear areas

Cons:

• Less flexible than modern acrylics (can crack)
• Yellows over time (especially whites)
• Longer drying times
• Harder cleanup, stronger odour
• More environmental impact

Best for: Trim work, doors, areas requiring super-hard finish, very cold application conditions.

Hybrid/Modified Acrylics

The best of both worlds. Premium products that combine acrylic flexibility with alkyd durability.

Pros:

• Excellent flexibility AND durability
• Great flow and levelling
• Good adhesion
• Faster recoat than traditional alkyds

Cons:

• More expensive
• Still can't apply in very cold conditions

Best for: High-end residential work, trims, anywhere you want the best finish.

Sheen Levels for Exteriors

Flat/Matt:

• Hides imperfections well
• Best for walls with texture or older surfaces
• Less durable, harder to clean
• Best for: Body of house on older weatherboards

Low Sheen:

• Slight sheen, good durability
• Still forgiving of surface imperfections
• Easy to clean, reasonable durability
• Best for: General house body, most residential work

Semi-Gloss:

• Noticeable sheen, very durable
• Shows surface imperfections
• Excellent cleanability
• Best for: Trims, window frames, doors, bargeboards

Gloss:

• High shine, maximum durability
• Shows every flaw
• Very easy to clean
• Best for: Front doors, feature trims, areas needing maximum protection

My recommendation for most NZ homes:

• House body: Low sheen
• Trims and bargeboards: Semi-gloss
• Front door: Semi-gloss or gloss
• Window frames: Semi-gloss

Brad's Honest Paint Recommendations

After 14 years and hundreds of exterior jobs, here's what I actually use:

For Premium Results:

• Resene Sonyx 101 – My go-to for house bodies. Excellent UV resistance, great flexibility, beautiful finish
• Dulux Weathershield – Solid performer, good all-round protection
• Resene Lumbersider – Reliable workhorse, excellent value for quality

For Trims and Details:

• Resene Lustacryl – Semi-gloss waterborne enamel, great durability
• Dulux Aquanamel – Excellent flow, hard finish

For Cedar and Natural Timber:

• Resene Woodsman – Penetrating stain, lets timber breathe
• Sikkens Cetol – Premium system, excellent UV protection
• Dryden WoodOil – My favourite for cedar in Central Otago

What I avoid:

• Anything under $80 per 10L (you get what you pay for)
• Unbranded or "contractor grade" paint
• One-coat promises (they're marketing, not reality)

Part 3: Surface Preparation (Where the Real Work Happens)

I'll say it plainly: preparation is 70-80% of a successful exterior paint job. Skip it, rush it, or do it badly, and your beautiful paint will fail – often within 2-3 years.

Assessing Your Exterior

Before you buy a single tin of paint, you need to understand what you're working with.

Walk the entire house and check for:

Structural Issues:

• Rotten timber (poke with a screwdriver – soft is bad)
• Damaged weatherboards or cladding
• Failed flashings around windows and doors
• Gaps in joints and corners
• Damaged or missing sealant

Paint Condition:

• Peeling or flaking paint
• Chalking (rub your hand on it – powder means chalking)
• Cracking (alligator pattern means paint failure)
• Blistering or bubbling
• Bare timber showing through

Surface Issues:

• Mould, mildew, or algae growth
• Lichen or moss
• Dirt and grime buildup
• Old filler failures
• Rust stains (from nails or metal)

Document everything. Take photos. Create a list. This determines your preparation approach and helps you quote materials accurately.

The Preparation Process (In Order)

Step 1: Repairs First

Before any paint prep, fix structural issues:

• Replace rotten timber sections
• Re-fix loose weatherboards
• Repair or replace damaged flashings
• Fill large gaps with appropriate exterior filler
• Replace any failed sealant

Brad's tip: In Central Otago, I use Sikaflex PRO-3 for exterior sealing. It handles our temperature extremes without cracking. The cheap stuff from the hardware store? It'll fail within two years.

Step 2: Washing

Every exterior needs washing. No exceptions.

The Right Way:

1. Start with a garden hose to remove loose dirt
2. Apply exterior house wash or sodium hypochlorite solution (1:10 for mould)
3. Let it dwell for 10-15 minutes (don't let it dry)
4. Soft wash with low-pressure water (not a high-pressure blaster on timber)
5. Rinse thoroughly from top to bottom
6. Allow 2-3 days minimum drying time (longer in cooler conditions)

The Wrong Way:

• High-pressure blasting timber (damages the surface, forces water into grain)
• Using the wrong chemicals (some damage paint)
• Not rinsing properly (residue prevents adhesion)
• Painting before fully dry (biggest cause of paint failure)

For Mould/Mildew:

• 30-Second Outdoor Cleaner works well
• Or mix sodium hypochlorite (pool chlorine) 1:10 with water
• Apply, let dwell, scrub stubborn areas, rinse thoroughly
• Treat again if mould returns before painting

For Lichen/Moss:

• Scrape off what you can
• Treat with moss and mould killer
• Allow time for complete kill before washing off

Step 3: Scraping and Sanding

This is the grunt work that separates professional results from DIY disasters.

The Tools You Need:

• Carbide scraper (Bahco or similar quality)
• Various scrapers for different profiles
• Detail scraper for window frames
• Orbital sander with extraction
• Hand sanding blocks
• Various grits: 60, 80, 120, 180

The Process:

1. Scrape all loose, peeling, or flaking paint
2. Feather edges where good paint meets bare timber (creates smooth transition)
3. Sand all surfaces to create "tooth" for new paint
4. Focus extra attention on areas with chalking
5. Vacuum or brush off all dust

Scraping Tips:

• Work with the grain on timber, never against
• Keep scrapers sharp (resharpening takes seconds)
• Don't gouge the timber – you're removing loose paint, not carving wood
• Wear safety glasses – paint chips fly

Sanding Schedule:

• Bare timber: 80 grit, then 120 grit
• Existing paint in good condition: 180 grit scuff sand
• Window frames and trims: 120 grit, then 180 grit
• Previously chalked surfaces: 120 grit thorough sand

Step 4: Filling and Caulking

Now address all the gaps, holes, and imperfections.

For Holes and Dents:

• Use exterior-grade filler (Selleys Exterior Gold or similar)
• Apply slightly proud of the surface (it shrinks)
• Allow full cure before sanding
• Sand flush with surrounding surface

For Gaps and Joints:

• Exterior sealant for moving joints (Sikaflex, Bostik)
• Paintable sealant is essential
• Tool the sealant smooth with a wetted finger
• Don't overfill – you want a slight concave profile

For Nail Holes:

• Punch any proud nails below surface
• Fill with exterior filler
• Spot prime before full coat

Central Otago Specific: Our temperature swings mean joints move more than most places. I always use flexible sealant (not rigid filler) for any joint that might move – window frames, corner boards, anywhere two surfaces meet.

Step 5: Priming

This is the step that determines whether your paint job lasts 5 years or 15 years.

When You Must Prime:

• Bare timber (always)
• Galvanised metal (specific primer required)
• Previously chalked surfaces
• Spot repairs and patches
• When changing paint systems (e.g., oil to acrylic)
• Any surface with stains or tannin bleed

Primer Types:

For Timber:

• Resene Wood Primer (excellent for our conditions)
• Dulux 1 Step Prep (good all-rounder)
• Oil-based wood primer for maximum sealing (older/weathered timber)

For Metal:

• Galvanised iron primer (for new galv – must etch first)
• Rust-converting primer for any rust spots
• Metal primer for aluminium

For Stains (Tannin, Water Marks):

• Zinsser BIN (shellac-based – seals anything)
• Resene Sureseal (good stain blocking)

Application Tips:

• Apply primer to all bare surfaces within 24 hours of sanding
• Don't thin primer unless specified (it's formulated for a reason)
• Ensure complete coverage – missed spots will fail
• Allow full cure before topcoat (check tin – usually 24 hours minimum)

Part 4: Application Techniques

Your surfaces are prepped, your primer is cured, and you're ready for the main event.

Weather Windows

Ideal Conditions:

• Temperature: 15-25°C (absolutely critical)
• Humidity: Below 85%
• Wind: Light to moderate (not dead calm, not gale force)
• Forecast: No rain for 24-48 hours minimum
• Surface: Dry and not too hot to touch

Don't Paint When:

• Temperature below 10°C (paint won't cure properly)
• Temperature above 30°C (paint dries too fast, poor film formation)
• Humidity above 85% (paint won't dry, moisture issues)
• Heavy dew expected (common in Central Otago mornings)
• Rain forecast within 24 hours
• Direct hot sun on the surface (wait for shade)

Central Otago Timing:

• Best months: October-April
• Best time of day: Follow the shade around the house
• Paint east walls in afternoon, west walls in morning
• Allow for cold mornings – don't start too early

Coastal Area Timing:

• Watch humidity levels carefully
• Morning dew burns off later
• More rain delays to factor in

Brush, Roller, or Spray?

Brushing:

• Best for: Trims, window frames, detail work, cutting in
• Pros: Maximum control, works paint into surface, best adhesion
• Cons: Slow, brush marks possible, tiring

Rolling:

• Best for: Large flat areas, weatherboard faces
• Pros: Fast coverage, consistent finish, less tiring
• Cons: Can't get into corners, texture depends on roller nap

Spraying:

• Best for: Large areas, new builds, rough textures
• Pros: Fastest, consistent finish, gets into every nook
• Cons: Overspray issues, masking required, weather sensitive, skill required

My Approach for Most NZ Weatherboard Homes:

1. Cut in all edges and details with brush
2. Roll the board faces
3. Back-brush to work paint into the surface and eliminate roller texture
4. Spray only for large, simple surfaces or rough textures

The Actual Painting Process

For Weatherboards:

1. Set up properly

   • Lay drop sheets (canvas, not plastic – plastic is slippery)
   • Have all tools ready and accessible
   • Ensure good ladder safety (level base, tied off if possible)

2. Cut in first

   • Paint all edges, corners, and details with brush
   • Work about 1-1.5 metres ahead of where you'll roll
   • Don't let the cut-in dry before rolling into it

3. Apply first coat

   • Load roller evenly (not dripping)
   • Apply in a W pattern, then spread evenly
   • Work in sections you can complete while maintaining a wet edge
   • Back-brush on timber to work paint into the grain
   • Don't overwork – lay it off and leave it

4. Check your work

   • Look for holidays (missed spots)
   • Check for runs and sags
   • Address any issues immediately while wet

5. Allow proper drying

   • Check tin for recoat time (usually 2-4 hours minimum)
   • Longer in cool or humid conditions
   • Don't rush this – proper cure between coats is essential

6. Apply second coat

   • Light sand if more than 7 days between coats
   • Apply as per first coat
   • This is your finish coat – take extra care

For Trims and Details:

1. Prepare the surface

   • Extra attention to sanding – trims show every imperfection
   • Fill all holes and dents
   • Prime any bare spots

2. Apply paint carefully

   • Use quality brush appropriate for trim work
   • Load brush properly – dip 1/3 into paint, tap off excess
   • Apply paint along the grain
   • Lay off with light strokes in one direction
   • Maintain wet edge at all times

3. Second coat

   • Light sand between coats (220 grit)
   • Apply as above
   • Check for runs before they set

How Many Coats?

The Minimum:

• Two coats over properly primed surfaces
• This is non-negotiable for durability

When You Need More:

• Changing from dark to light colour (3+ coats often needed)
• Very absorbent surfaces
• High-exposure areas (full north-facing walls)
• Premium finishes requiring perfect coverage

The False Economy of One Coat: I see "one coat" paints marketed constantly. Here's the reality: they might give reasonable coverage in one coat, but you won't get the film thickness needed for durability. That "one coat" paint job will need redoing in 5 years. Two coats of quality paint will last 10-15.

Part 5: Special Situations

Painting Weatherboards

Weatherboards are the classic NZ exterior cladding, and they have specific requirements.

Board Preparation:

• Check for loose or sprung boards (re-nail before painting)
• Look for splits and cracks (fill with flexible filler)
• Examine bottom edges (most moisture damage starts here)
• Check behind downpipes (often neglected, often rotting)

Painting Sequence:

1. Bottom edge of each board first (most critical area)
2. Face of board
3. Top edge/rebate
4. Don't forget the undersides of boards at foundation level

Common Weatherboard Mistakes:

• Not painting the bottom edges (invites moisture)
• Painting in direct sun (dries too fast)
• Thick coats that sag at the rebate
• Missing the areas behind downpipes and fixtures

Cedar and Natural Timber

Cedar is beautiful but requires a different approach than painted weatherboards.

Stain vs Paint:

• Stains penetrate the timber and let it breathe
• Paint sits on top and can trap moisture
• For cedar, I always recommend stain/oil systems

Cedar Preparation:

• Clean thoroughly (cedar releases natural oils)
• Light sand to open the grain
• Never use heavy-duty strippers on cedar (damages the surface)
• Allow to dry completely (cedar holds moisture)

Application:

• Apply liberally – cedar is thirsty
• Work stain into the grain with brush
• Don't allow to puddle
• Two coats minimum, three for exposed areas
• Maintain every 2-3 years in Central Otago (more frequently than paint)

[For more on cedar maintenance, see my Cedar Re-Staining Cost Planner.]

Painting Over Old Alkyd/Oil Paint

If your house was painted before ~2000, there's a good chance it has oil-based paint underneath.

How to Test:

• Wipe a small area with methylated spirits on a rag
• If paint softens or comes off, it's acrylic
• If nothing happens, it's alkyd/oil

The Conversion Process:

1. Wash thoroughly (oil paints can have oily residue)
2. Sand well to create mechanical adhesion
3. Apply bonding primer (Resene Sureseal or similar)
4. Topcoat with acrylic system

Why This Matters: Acrylic paint doesn't adhere well directly to oil paint. That bonding primer creates a bridge between systems. Skip it, and you'll get peeling within a year or two.

Dealing with Lead Paint

If your house was painted before 1970, assume there's lead paint somewhere.

Legal Requirements:

• Testing required before disturbance
• Specific work practices for removal
• Proper disposal of waste
• Not a DIY job if lead is present

My Recommendation: If you suspect lead paint, get it tested first. If positive, either encapsulate it (paint over without disturbing) or hire a professional with lead-safe certification. The health risks aren't worth the savings.

Exterior Plaster and Stucco

The Challenge:

• Cracks let water in
• Hollow sections indicate delamination
• Texture makes preparation tricky

Preparation:

• Fill all cracks with elastomeric filler
• Address any hollow areas (may need professional repair)
• Wash thoroughly – texture traps dirt
• Prime any repairs

Paint Selection:

• Elastomeric paints are excellent for cracked stucco
• They bridge small cracks and flex with movement
• More expensive but worth it for problem surfaces

Brick and Masonry

Important Considerations:

• New brick/concrete must cure before painting (typically 4+ weeks)
• Efflorescence (white salt deposits) must be addressed first
• Proper masonry primer is essential

Preparation:

• Remove efflorescence with stiff brush (don't wash it in)
• Treat any mould or biological growth
• Allow to dry completely
• Apply masonry sealer/primer

Paint:

• Use paints specifically designed for masonry
• They're formulated to handle alkalinity
• Allow for proper breathability

Part 6: The Real Costs (No BS Edition)

Let's talk actual numbers. These are 2025/2026 prices for Central Otago – adjust slightly for other regions.

DIY Costs

Materials for a Typical 150m² Weatherboard Home:

Total DIY Materials: $2,300-$3,400

But wait – add at least $500-$800 for the things you'll discover you need mid-project. And that's not counting your time.

Time Investment:

• Washing and drying: 2-3 days (including drying time)
• Scraping and prep: 5-7 days (the real work)
• Priming: 1-2 days
• First coat: 2-3 days
• Second coat: 2-3 days
• Trims and details: 3-4 days

Total: 16-22 working days for DIY

If you're doing weekends only, that's 2-3 months of solid work. Factor in weather delays, and you're looking at potentially an entire summer.

Professional Costs

Regional Rates (per m² of paintable surface):

For a Typical 150m² Weatherboard Home:

What's Included:

• All materials (paint, primer, sundries)
• Full preparation (washing, scraping, sanding, filling)
• Two-coat premium paint system
• Professional finish and cleanup
• Workmanship warranty (typically 5-7 years)

What's Extra:

• Scaffolding (if required): $1,500-$5,000
• Major repairs (rotten timber, etc.): Quoted separately
• Colour changes (dark to light): +15-25%
• Premium paint upgrades: +10-20%

The Real Comparison

DIY:

• Materials: $2,800-$4,200 (including forgotten items)
• Time: 16-22 days of hard work
• Quality: Variable (depends on your skill)
• Durability: 5-10 years (if done well)
• Warranty: None

Professional:

• Cost: $6,000-$13,000
• Time: 5-10 days (you're not involved)
• Quality: Consistent professional standard
• Durability: 10-15 years
• Warranty: 5-7 years workmanship

My Take: If your time is worth less than $25/hour, you have the physical fitness for the work, and you're comfortable on ladders, DIY can make sense.

If your time is valuable, you hate heights, or you want guaranteed results, hire a professional. The peace of mind and quality outcome is worth the difference.

[For a deeper dive into this question, see my DIY or Hire a Pro Cost Breakdown.]

Part 7: Hiring a Professional (What to Look For)

If you've decided to hire someone, here's how to separate the professionals from the cowboys.

What to Ask

1. "Can you show me recent work in this area?" Good painters have portfolios. Great painters can point you to houses in your neighbourhood. Drive by and look at the quality.

2. "What's your preparation process?" Listen carefully to this answer. If it doesn't include washing, scraping, sanding, and priming, walk away. "We'll just give it a light sand" is not acceptable.

3. "What paint system will you use?" Specific brands and products should be mentioned. If they say "whatever's cheapest" or can't name the products, that's a red flag.

4. "What's included in your quote?" Get everything itemised. Preparation, paint, coats, scaffolding, cleanup – it should all be there.

5. "What's your warranty?" Minimum 5 years workmanship warranty. They should be able to explain exactly what's covered.

Red Flags

• No fixed business address – Legitimate businesses have more than a mobile number
• Cash only – Tax dodging that leaves you unprotected
• Won't provide written quote – Verbal agreements are worthless
• Massively cheaper than others – There's always a reason
• Pressure to decide immediately – Good contractors are booked out
• Can't provide references – Everyone has happy customers if they do good work
• Vague about paint brands – They're probably using cheap product

The Quote Process

Get Three Quotes: Not to price shop, but to understand the scope differences. If one quote is half the price of the others, they're not quoting the same job.

Compare Like for Like:

• Same preparation steps
• Same paint quality (brand and product line)
• Same number of coats
• Same inclusions (scaffolding, repairs, etc.)

Ask Questions: Don't be afraid to query differences. A good contractor will explain their approach.

[For more on this topic, see my How to Choose a Painter guide.]

Part 8: Maintaining Your Exterior Paint

You've invested thousands in your exterior paint job. Here's how to make it last.

Annual Maintenance (Every Year)

Autumn:

• Clean gutters (overflow damages paint)
• Check for any obvious paint failures
• Clear vegetation from walls
• Check sealant around windows and doors

Spring:

• Wash the house (gentle hose or soft wash)
• Inspect for winter damage
• Touch up any minor chips or scratches
• Check north-facing walls for chalking

Regular Maintenance (Every 2-3 Years)

• Full exterior wash with appropriate cleaner
• Re-caulk any failing joints
• Touch up any damaged areas before they spread
• Inspect all edges and bottom of boards
• Check behind downpipes and fixtures

Warning Signs (Time to Act)

Early Warning (Address Now):

• Minor chalking
• Small chips or scratches
• Sealant shrinking or cracking
• Minor discolouration

Moderate Warning (Schedule Maintenance):

• Noticeable chalking
• Multiple chips or scratches
• Sealant failures
• Fading (especially reds and blues)

Urgent Warning (Repaint Needed):

• Peeling or flaking
• Bare timber exposed
• Alligator cracking
• Extensive mould or mildew
• Multiple areas failing

Extending Paint Life

The things that destroy paint fastest:

1. Water intrusion (failed gutters, splashback, poor drainage)
2. UV exposure (especially north-facing walls)
3. Vegetation against walls (traps moisture, causes physical damage)
4. Salt spray (coastal areas)
5. Deferred maintenance (small problems become big problems)

What you can do:

• Keep gutters clear and functioning
• Maintain 300mm clearance from walls to vegetation
• Wash your house annually
• Address small issues immediately
• Consider UV-protective clear coats on high-exposure areas

Part 9: Common Mistakes (And How to Avoid Them)

After 14 years, I've seen every mistake possible. Here are the ones I see most often:

Mistake 1: Painting Over Problems

"The paint will cover it" is the most expensive lie in exterior painting.

Common Offenders:

• Painting over rotten timber (rot continues underneath)
• Painting over mould (mould grows through)
• Painting over loose paint (peels within months)
• Painting over dirty surfaces (paint won't adhere)

The Fix: Address the underlying problem first. Always.

Mistake 2: Wrong Weather

Painting in wrong conditions ruins more jobs than poor technique.

Common Offenders:

• Painting when it's too cold (paint won't cure)
• Painting in direct hot sun (dries too fast)
• Painting with rain coming (moisture issues)
• Not allowing drying time between coats

The Fix: Check weather forecasts obsessively. Wait for ideal conditions. There's no such thing as "good enough" weather for exterior painting.

Mistake 3: Insufficient Preparation

The grunt work nobody wants to do. Skip it at your peril.

Common Offenders:

• Minimal scraping (leaving loose paint)
• No sanding (no adhesion)
• Skipping primer (paint fails)
• Poor washing (dirt under paint)

The Fix: Budget 60-70% of your time for preparation. If you're spending most of your time painting, you're doing it wrong.

Mistake 4: Cheap Paint

The difference between $50/10L and $100/10L paint is enormous.

What Cheap Paint Lacks:

• Quality resins (affects adhesion and durability)
• Good pigments (fading, poor coverage)
• UV stabilisers (essential in NZ)
• Flexibility (cracking in our climate)

The Fix: Budget properly for quality paint. It costs more per tin but lasts 2-3 times longer. That $400 you "saved" on cheap paint will cost $4,000 when you're repainting in 5 years instead of 15.

Mistake 5: Wrong Product for the Job

Using interior paint outside. Trim paint on walls. One product for everything.

Common Offenders:

• Interior paint on protected areas (it's still outside)
• Wall paint on trims (not durable enough)
• One sheen for everything (wrong for the application)
• Not using appropriate primer

The Fix: Different surfaces need different products. Consult with your paint supplier about the specific requirements of each surface.

Mistake 6: Inadequate Coverage

One thick coat instead of two proper coats.

The Problem:

• Thick coats sag and drip
• Thick coats don't cure properly inside
• One coat doesn't give adequate film thickness
• Coverage isn't the same as protection

The Fix: Two proper coats, minimum. No exceptions. This is non-negotiable for durability.

Part 10: The Climate-Specific Checklist

For Queenstown/Wanaka/Central Otago

Essential Considerations:

• UV-resistant paint system (premium grade minimum)
• Flexible paint formulation (handles temperature swings)
• Application in ideal temperature range only
• Extra attention to north-facing walls
• Flexible sealant on all joints
• Allow for extreme temperature cure times
• Plan around frost – no painting if overnight frost expected
• Consider altitude UV when selecting colours (fading is accelerated)

Best Timing: October-April, avoiding peak summer heat on north walls

For Coastal Areas

Essential Considerations:

• Salt-resistant paint system
• Extra preparation for salt deposits
• Mould-resistant additives if needed
• More frequent maintenance schedule
• Pay attention to wind direction (salt spray patterns)
• Corrosion-resistant primers for any metal
• Higher humidity means longer dry times

Best Timing: Settled weather periods, autumn often good

For Southern Regions

Essential Considerations:

• Mould and mildew prevention
• Longer dry times in cool/damp conditions
• Moss and lichen treatment
• Paint system suitable for lower temperatures
• Moisture barrier considerations
• Allow extra time for cure

Best Timing: December-March typically best, watch for settled weather

Final Thoughts: Is It Worth Doing Right?

Here's what I know after 14 years of exterior painting:

A properly prepared, quality paint job protects your home for 10-15 years. It prevents rot, moisture damage, and the slow degradation that turns small problems into expensive disasters.

A shortcut paint job – poor prep, cheap paint, wrong conditions – fails in 3-5 years. And when it fails, you're not just redoing the paint. You're dealing with the damage that accumulated underneath.

The maths is simple:

Quality job: $10,000 every 15 years = $667/year Cheap job: $4,000 every 5 years + $3,000 repairs = $1,400/year

Doing it right costs half as much in the long run.

So whether you're DIYing or hiring a pro, invest in preparation. Use quality materials. Follow proper technique. Your house – and your bank account – will thank you.

Need professional exterior painting in Central Otago? Little Dog Decorating in Queenstown offers quality exterior painting with proper preparation and premium paint systems. For Wanaka homeowners, Painters Wanaka specialises in weatherboard and exterior finishes designed for our local climate. Both offer free quotes and stand behind their work.

Quick Reference: Brad's Exterior Painting Cheat Sheet

Preparation Checklist:

• Repair any structural issues first
• Wash thoroughly (2-3 days drying minimum)
• Scrape all loose paint
• Sand all surfaces (120-180 grit)
• Fill holes and cracks
• Caulk all joints with flexible sealant
• Prime all bare surfaces
• Allow primer to cure fully

Weather Requirements:

• Temperature: 10-25°C
• Humidity: Below 85%
• No rain: 24-48 hours minimum
• Surface: Dry and not too hot

Paint Quantities (Rough Guide):

• Coverage: 10-12m² per litre (one coat)
• 150m² house body: ~30-40L for two coats
• Trims add 10-15L typically
• Always order 10-15% extra

Coats Required:

• Minimum: Two coats over properly primed surfaces
• Colour change (dark to light): Three or more coats
• New timber: One primer + two topcoats

Maintenance Schedule:

• Annual: Visual inspection, gutter cleaning
• 2-3 years: Wash, touch-up, re-caulk
• 10-15 years: Full repaint (quality system)
• 5-8 years: Full repaint (budget system)

Emergency Numbers:

• Leaking paint tin on carpet? Sugar soap and warm water immediately
• Paint on windows? Single-edge razor blade at 45 degrees
• Runs and sags? Catch within 15 minutes or wait until fully cured to sand

Got questions about your specific exterior project? Drop a comment below or reach out through the contact page. I'm always happy to help fellow Kiwis protect their homes properly.