Roof washing in New Zealand typically costs $500 to $2,500+ GST, depending on roof size, access, and condition. It is the most intensive roof cleaning option and delivers instant results, making it suitable for roofs with heavy moss, mould, or lichen buildup.
Unlike cheaper roof treatments that work over time, roof washing removes contamination immediately using soft wash chemicals and controlled pressure cleaning.
This guide explains current roof washing costs, what’s included, and when roof washing is the right choice compared to roof treatment.
What Is Roof Washing?
Roof washing is a deep, immediate-clean method used when a roof has heavy moss, mould, lichen, or ingrained dirt that cannot be fixed with treatment alone.
What homeowners need to know first:
- Roof washing delivers instant visual results
- It combines soft wash chemicals with controlled pressure cleaning
- It physically removes contamination instead of waiting for rain to do the work
How it works:
- A soft wash solution is applied to loosen moss, mould, and lichen
- Controlled pressure is used to safely remove buildup
- The roof surface is fully cleaned, not just treated
Roof washing is typically recommended when:
- Moss or lichen is thick and established
- The roof looks dark, patchy, or heavily stained
- Immediate results are required (sale, insurance, compliance)
Because it involves more labour, water, safety equipment, and risk, roof washing costs more than roof treatment and is always assessed first.
How Much Does Roof Washing Cost in New Zealand?
Roof washing is priced higher than other roof cleaning options because it involves manual labour, safety systems, water use, and controlled pressure cleaning.
What homeowners need to know upfront is that roof washing is not a fixed-price service. It is almost always confirmed after inspection.
Typical roof washing cost range in New Zealand:
- $500 – $2,500+ GST
- Larger, steeper, or high-risk roofs can exceed this range
Below is an indicative pricing guide to help you understand how size affects cost.
| Roof Size (sqm) | Estimated Cost Range (NZD) |
|---|---|
| Up to 100 sqm | $500 – $700 + GST |
| 100–150 sqm | $700 – $1,000 + GST |
| 150–200 sqm | $1,000 – $1,400 + GST |
| 200–250 sqm | $1,400 – $1,800 + GST |
| 250–300 sqm | $1,800 – $2,200 + GST |
| 300+ sqm | $2,200 – $2,500+ + GST |
Important notes:
- These are guide prices only
- Final pricing is confirmed after inspection or photo assessment
- Roof pitch, height, material, access, and contamination level can move pricing up or down
If you are quoted a fixed price without inspection, the quote is either padded or incomplete. Roof washing should always be priced based on the actual roof risk and condition, not guesswork.
Roof Washing Cost Per Square Metre (Industry Guide)
Roof washing is rarely advertised per square metre, but when broken down, most professional roof washing jobs in New Zealand typically work out to:
$6 – $15 per sqm + GST
This range helps homeowners understand why prices vary so widely between properties.
What pushes the cost toward the higher end:
- Steep or high-pitched roofs that require extra safety measures
- Two-storey homes or roofs with difficult access
- Fragile roofing materials such as older tiles or concrete roofs
- Heavy moss, mould, or lichen buildup
- Complex roof layouts with valleys, hips, or multiple levels
Why sqm pricing is only a guide:
- Safety setup time is the same whether a roof is small or large
- Water usage and labour increase unevenly on complex roofs
- Risk level matters more than size alone
That’s why roof washing is almost always priced after inspection, even though sqm ranges give a useful benchmark for understanding overall cost.
What’s Included in a Professional Roof Wash?
A professional roof wash is more than just spraying water. It is a structured process designed to clean the roof safely and completely, while protecting the property and people below.
A proper roof washing service typically includes:
1. Full roof inspection
Assessment of roof material, pitch, height, and contamination level before any work begins.
2. Soft wash chemical application
Specialised solutions are applied to break down moss, mould, lichen, and organic buildup without damaging the roof surface.
3. Controlled pressure cleaning
Pressure is carefully adjusted to remove loosened growth without stripping coatings or damaging tiles.
4. Complete removal of moss, mould, lichen, and grime
This delivers immediate visual improvement across the entire roof.
5. Safety equipment and fall protection
Harnesses, edge protection, and access systems are used where required to manage risk.
6. Clean-up of surrounding areas
Debris washed off the roof is cleared from gutters, walls, paths, and gardens.
If a service skips inspection, safety measures, or cleanup, it is not a full roof wash. These steps are what make roof washing effective, safe, and worth the cost.
Why Roof Washing Is More Expensive Than Roof Treatment
Roof washing costs more because it is labour-intensive, higher risk, and delivers instant results. Homeowners should understand this difference before choosing between the two.
Here’s the direct comparison that matters:
| Roof Treatment | Roof Washing |
|---|---|
| Gradual results over weeks or months | Instant visible results |
| Chemical application only | Soft wash + controlled pressure cleaning |
| Minimal water use | High water use |
| Lower labour | High labour and setup time |
| Lower safety risk | Higher safety and fall-protection requirements |
| Lower cost | Higher cost |
Why roof washing costs more:
- Technicians spend more time on the roof
- Safety systems and access equipment are required
- More water and controlled pressure are used
- Risk level is significantly higher
- Cleanup is more extensive
Roof washing is not better for every roof. It is the right option only when contamination is heavy or immediate results are required. In many cases, roof treatment is the smarter and more cost-effective choice.
Why Is Roof Washing Priced “On Inspection”?
Roof washing cannot be priced accurately without seeing the roof. What homeowners need to know is that every roof carries a different level of risk, and risk drives the cost.
During an inspection, the following factors are assessed:
- Roof size
Larger roofs increase labour time and water use. - Roof pitch (steepness)
Steeper roofs require additional safety equipment and slower working speeds. - Roof height
Double-storey homes or elevated sections increase fall risk and setup time. - Roofing material
Iron, tile, concrete, and older roofs all require different pressure levels and techniques. - Level of moss and contamination
Heavy, established growth takes longer and requires more controlled cleaning. - Access and safety requirements
Limited access, surrounding obstacles, or complex roof layouts add setup and labour time.
Photos or an on-site inspection allow pricing to be fair and accurate, rather than inflated to cover unknowns. If roof washing is quoted without inspection, the price is either padded or unreliable.
Is Roof Washing Worth the Cost?
Roof washing is worth the cost only when it is the right solution for the roof’s condition. It is not a maintenance clean. It is a corrective clean.
Roof washing makes sense when:
- Moss, lichen, or mould is heavy and established
- The roof looks dark, patchy, or badly stained
- Immediate visual results are required (selling, insurance, compliance)
- Roof treatment alone will not be effective
When roof washing may not be worth it:
- Light moss or early growth is present
- The goal is long-term prevention rather than instant appearance
- Budget is a concern and time is not critical
Cost vs damage comparison:
- Ignoring heavy moss can lead to lifted tiles, coating failure, and leaks
- Repairing roof damage costs far more than a one-time wash
Roof washing is expensive, but in the right situation, it prevents bigger costs and restores the roof immediately. The key is choosing it for the right reasons, not by default.
Roof Washing vs Roof Treatment: Which Should You Choose?
The first thing to know is this: roof washing and roof treatment solve different problems. Choosing the wrong one either wastes money or delays results.
Choose roof washing if:
- Moss, lichen, or mould is thick and well established
- You need instant visual improvement
- The roof is being prepared for sale, inspection, or compliance
- Treatment alone will not break down existing growth
Choose roof treatment if:
- Growth is light or early-stage
- You want long-term prevention, not immediate appearance
- Budget matters more than speed
- The roof structure is sound and not heavily stained
Simple decision guide:
- Heavy growth + urgent results → Roof washing
- Light growth + preventative care → Roof treatment
Roof washing fixes a problem now.
Roof treatment prevents a problem later.
How Sun SoftWash Approaches Roof Washing
What homeowners need to know first is this: roof washing is not always the right solution, and Sun SoftWash does not recommend it unless it is genuinely needed.
Here’s how Sun SoftWash approaches roof washing:
- Inspection-first, not price-first
Every roof is assessed before recommending a wash. Size, pitch, material, contamination level, and safety risk are all considered. - Treatment preferred where possible
If roof treatment will solve the problem safely and at a lower cost, that option is recommended instead of washing. - Safety-led process
Roof washing is only carried out when proper access, fall protection, and surface suitability are confirmed. - Controlled methods, not aggressive cleaning
Soft wash chemicals and controlled pressure are used to clean effectively without damaging coatings or tiles. - Clear, honest pricing
Pricing is explained after inspection so homeowners understand exactly what they are paying for and why.
FAQs About Roof Washing Costs
Can roof washing damage my roof?
If done incorrectly, yes. High pressure or poor technique can damage tiles, coatings, and fixings. Professional roof washing uses controlled pressure and surface-safe methods to reduce risk.
How long does roof washing take?
Most residential roofs take half a day to a full day, depending on size, pitch, and contamination level.
Does roof washing include gutter cleaning?
Debris is usually cleared from surrounding areas, but full gutter cleaning may be a separate service. Always confirm what’s included in the quote.
How often should a roof be washed?
Roof washing is not routine maintenance. It’s typically a one-off corrective service. Ongoing protection is better handled with roof treatment.
Is roof washing safe for older roofs?
It depends on the roof’s condition and material. Older or fragile roofs require inspection first and may be better suited to treatment instead.
Why are some quotes much cheaper than others?
Lower prices often mean no safety setup, aggressive pressure, or incomplete cleaning. Roof washing should never be judged on price alone.
