Service
Moss and lichen treatment for Wellington roofs
Biocide treatment that kills moss and lichen at the root, typically stretches roof life by another 5–10 years.
What's included
- Have a look at the roof first, type, age, how bad the growth is
- Initial gutter clearance
- Biocide chemistry on evenly across the roof
- Dwell, left to work over 4–12 weeks (no rinse needed)
- Optional return visit for heavy-buildup roofs
- Plant and surrounding-area protection
- Documented before-and-after photos when it's done
Why this matters in Wellington
Wellington's combination of annual rainfall (~1,200mm), prevailing southerlies, and the porous concrete-tile roofing on a lot of 1970s–80s housing stock makes moss and lichen the most common roofing problem James sees. The right treatment matters because heavy moss or lichen holds moisture against the roof coating year-round, speeds up wear, and shortens roof life by 5–10 years if it's left alone. Regular treatment (every 2–3 years for most properties) is one of the cheapest forms of roof life-extension going.
Moss and lichen on a Wellington roof are unavoidable, the wet southerly climate, the shaded valleys, and the porous concrete-tile roofing on a lot of 1970s–80s housing stock all conspire. What’s avoidable is the accelerated roof wear that comes from letting moss hold moisture against the tiles year after year.
Moss treatment is different from a roof wash. A wash physically takes off what’s there on the day; a treatment chemically kills moss and lichen at the root, so the roof stays clean for 2–3 years instead of 12–18 months. Plenty of customers do both, wash first to get rid of the visible buildup, then treat 6 weeks later to keep regrowth at bay.
Typical Wellington moss treatments run $320–850 depending on roof area, pitch and how bad the buildup is.
Recent jobs
Moss & Lichen Treatment, before and after.
during 
FAQ
Moss & Lichen Treatment, common questions
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What's the difference between moss treatment and a roof wash?
A roof wash physically takes moss and lichen off on the day. A moss treatment chemically kills it, roots and all, over the following weeks. Treatment lasts longer (often 2–3 years before any real regrowth) and stops the accelerated roof wear. Plenty of homeowners do both, wash first to get rid of the visible buildup, then treat 6 weeks later to keep it from coming back.
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How long does moss treatment last?
Typically 2–3 years before any real new growth shows up. South-facing Wellington roofs (Newlands, Brooklyn, Kelburn upper streets) get visible regrowth sooner; north-facing roofs can stretch to 4 years.
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Will it damage my roof or coating?
No. The biocide chemistry is formulated for roof coatings (concrete tile, Decramastic, Coloursteel, terracotta). It's the high-pressure water blasting that damages coatings, not the chemistry. Treatment is gentler than washing.
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Is the chemistry safe around plants and pets?
Yes when applied correctly. James uses biodegradable biocides at controlled concentrations, rinses plants down before and after, and keeps pets indoors during application and the immediate dwell (a few hours).
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Why is treatment cheaper than a full wash?
Because there's no rinse phase. Wash jobs spend hours on the physical removal and rinsing; treatment is faster on site and lets nature do the rest. The downside, the result takes weeks to look fully clean. The upside, the result lasts longer.
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Can I do it myself with Wet & Forget?
Wet & Forget and similar consumer biocides work fine on light buildup but they're dilute compared with professional treatment. For heavy moss and lichen, the consumer products take many seasons to fully work. Professional treatment uses higher-concentration chemistry, on evenly, by someone who knows how much your roof type can take.
Ready for a cleaner property?
Most quotes are back within a few hours, sometimes the same afternoon. Fill in the form, James will take a look at your address, and you'll get a straight price with no obligation.