Roof Washing Christchurch

A clean roof lasts longer. Moss and lichen hold moisture against the surface, leaves pile up in valleys and behind chimneys, and on coastal sites salt collects in the places rain never reaches. None of that fails a roof overnight, but over years it shortens the life of tiles, coatings and fixings.

We clean roofs with a method chosen for the material, not one approach for every job. Steel gets a gentle wash that protects the coating. Concrete tiles get a moss treatment first, so the growth comes away without blasting the surface. If the roof is heading for a repaint, cleaning is the first stage of our roof painting service anyway.

Pricing: every roof gets a free on-site measure and an itemised written quote, with a fixed price agreed before any work starts.

Paint worn through or rust showing once the roof is clean? Recoating is covered under roof painting.

Why roof cleaning matters

Growth on a roof is more than a cosmetic issue. On concrete tiles, moss and lichen keep the surface damp and speed up erosion of the face of the tile. On steel, they keep the coating wet for long periods. Leaves that settle in valleys and against skylights dam water where it should run freely. Near the sea, salt settles in sheltered spots such as under eaves and around gutters, and that is usually where corrosion on a steel roof begins.

• Green or black growth on shaded roof planes and tiles
• Lichen patches that show as grey, yellow or orange spots
• Leaves and debris sitting in valleys, gutters and against chimneys or skylights
• A salty crust or dull, dirty areas under the eaves of coastal homes

Washing steel roofs and your warranty

COLORSTEEL's warranty conditions depend on the environment category your house sits in. In milder environments rain is enough to wash the open roof, but sheltered areas that rain does not reach still need regular cleaning. As the environment gets harsher, the manual washing interval shortens, from yearly to six monthly to three monthly, and accessories on very severe sites need cleaning every month. Missing that washing can affect a warranty claim. The category is set for each site, so we check it rather than assume it from the suburb.

On steel we use a low-pressure wash, a soft brush and a cleaner that is safe for the coating, with extra attention on unwashed areas, laps and fixings. If we find chalking, rust spots or failed screws, we photograph them and tell you whether a repair, a repaint or new COLORSTEEL longrun would be the sensible next step.

How It Works

Moss treatment on tile roofs

Concrete tiles are porous, so moss and lichen root into the surface. Killing the growth first means it can be removed with a gentle wash instead of aggressive blasting. Biocide treatments need time to work. Resene's Moss and Mould Killer, for example, is diluted and left for up to 48 hours before washing, and heavy growth may need a second application. Lichen often takes longer to let go than moss, and some residue is better left to weather off after treatment than forced off the tile.

Heavy concrete tile roofs are common on older Christchurch houses, and many of them took a shaking in 2010 and 2011. While we are on a tile roof we look for cracked or slipped tiles and loose ridge capping. If there are more than a handful, our tile roof repairs page explains how they are put right.

Asbestos and older roofs

WorkSafe New Zealand prohibits high-pressure water spray on material that contains asbestos. Its guidance treats anything over 350 kPa, or 50 psi, as high pressure and sets out infringement fees and court fines for breaches. Super Six and other fibre cement sheet, some cement tiles and some decramastic roofs laid before asbestos was phased out can contain it. WorkSafe points to a soft wash or chemical wash instead.

If your roof could contain asbestos, we arrange testing before any cleaning and only use low-pressure methods. For roofs in poor condition, replacement can be the safer long-term choice, and we can quote both so you can compare.

Protecting drains, tanks and gardens

Stormwater drains carry water to streams, rivers and the sea without treatment, so cleaning chemicals and moss sludge must not go down them. We block or disconnect downpipes where needed, catch the runoff, protect plants and lawns, and take the debris away with us. If you collect drinking water from the roof, we disconnect the tank before cleaning and tell you when it is safe to reconnect.

Christchurch conditions and what affects the cost

Christchurch is dry by New Zealand standards, so growth tends to be heaviest on shaded faces that stay damp after frost and dew, and under trees. Homes near mature trees, such as the London plane lined streets of Beckenham, also collect leaf litter in valleys and gutters each autumn. On the coast in New Brighton, Southshore and Sumner, salt is the bigger concern for steel roofs, which makes regular washing of sheltered areas worthwhile.

Roof cleaning is priced on the area and type of roof. The amount of growth, whether a treatment and return visit are needed, the pitch, height and access, runoff control, and whether you want the gutters cleared at the same time all affect the quote. Regular cleaning usually costs less over time than a heavy clean every few years. If gutters are the main problem, our gutter cleaning service can be booked on its own.

Why Choose Cheeky's Roofers for Roof Washing

Roof Washing FAQs

Roof Washing Across Christchurch

We cover every region: Central Christchurch, North Christchurch, East and Coastal Christchurch, South Christchurch and Port Hills, West Christchurch, Selwyn and Waimakariri.

Related Roofing Services

• Roof Painting
• Roof Inspections
• Roof Ventilation
• Re-Roofing
• Roof Repairs

Roof Washing Guides

• Roofing Near the Beach: New Brighton, Southshore and Sumner
• Do Gutter Guards Work in Christchurch? Leaves, Snow and Nor'westers

See the roof replacement cost guide or every service we offer.