If you're getting your roof painted, the wash beforehand matters as much as the paint. Skip it, or rush it, and the new coat can start peeling within a couple of years. That's an expensive way to learn.
We do pre-paint roof washes across Wellington, the Hutt Valley and Porirua. Here's why the wash matters, what it involves and how to time it with your painter.
Why a roof must be washed before painting
Paint needs to grip a clean, sound surface. A Wellington roof that's due for painting usually has a few things on it that stop that happening:
- Moss and lichen. Even dead lichen leaves a residue that paint sits on top of rather than bonding to.
- Chalky old paint. Weathered roof paint goes powdery. Paint over chalk and it lifts.
- Salt. Coastal roofs, from Plimmerton to the south coast, carry a film of salt. It attracts moisture and causes paint to fail early.
- Dirt and soot. Grime from roads, chimneys and the general city air builds up on every roof.
- Loose flaking paint. Anything already lifting needs to come off.
A proper pre-paint wash removes all of that so the new paint bonds to the roof itself.
What a pre-paint roof wash involves
We start by looking over the roof: what it's made of, how much growth there is, and whether there's any damage like rust holes or loose fixings that the painter or a roofer needs to know about.
Then we wash. On long-run iron, we use pressure washing to strip off growth, chalky paint and grime. On concrete tiles we adjust the method to suit their age and condition. Where there's heavy lichen, we treat it with a cleaning solution first so it lets go properly.
We protect gardens and the area around the house while we work, and we flush the muck that comes off the roof out of the gutters and downpipes rather than leaving it there.
Find out more on our roof cleaning Wellington page.
How long to wait before painting
The roof has to be completely dry before paint goes on. In a good fine spell, that can be quick. After a run of wet weather, or on a shaded roof that doesn't get much sun, it takes longer.
Your painter's paint system will have its own requirements, so check with them. As a rule, we suggest booking the wash a few days ahead of the painters so there's a buffer if the weather turns.
Don't leave it too long either. If weeks go by, dust and new growth start to settle and you may need a quick rinse before painting.
What your painter will expect
Most painters want the roof handed over clean, dry and free of growth and loose material. Some prefer to do their own prep. Others are happy to have a specialist wash it first. Ask your painter before you book anything, and tell us who the painter is so we can line up the timing.
If you haven't picked a painter yet, it's worth asking how they want the roof prepared when you get quotes. A painter who skips the wash to save time is one to think twice about.
Do the walls too
Washing the roof sends a lot of grime down the walls and over the spouting. If the house walls are being painted too, or just need a tidy up, get them washed after the roof, not before. Our house washing Wellington service includes pre-paint washes for walls as well.
The usual order is roof wash first, then walls, then painting.
Not painting yet?
If the roof is grubby but the paint's still in decent shape, you might not need a full pre-paint wash. A roof treatment in Wellington kills the moss and lichen and lets the weather clear it over the following months. It's a good way to keep the roof in shape until it's actually due for paint.
Wellington weather and timing
Roof painting in Wellington is mostly a late spring to autumn job, when there are enough dry, calm days in a row. Painters fill up fast in that window. Book your painter early, then book the wash to fit their start date.
We need dry and reasonably calm weather to wash a roof safely. If a strong wind or heavy rain is forecast, we'll move the job and let you know.
Prices depend on the roof size, pitch and condition. Call us on 027 303 8398 for a free quote. We're open seven days, 7am to 7pm.
Pre-paint roof wash questions
Does a roof really need washing before painting?
Yes. Paint doesn't bond properly to moss, lichen, chalky old paint or salt. Skipping the wash is one of the main reasons roof paint fails early.
How long after washing can the roof be painted?
Once it's completely dry. That depends on the weather and how much sun the roof gets. Check what your painter's paint system needs.
Should the roof or the walls be washed first?
The roof. Washing it sends grime down the walls, so do the walls afterwards.
Can you wash a Decramastic or tiled roof before painting?
We adjust the method to the roof type and its condition, with gentler handling on chip-coated and older tiles.