Painting weatherboard and rendered walls

For weatherboard: scrape what's loose, prime what's bare

Weatherboard is a cladding made up of overlapping timber boards that expand and contract with heat. That movement is why prep matters so much. Paint that isn't bonded to something solid peels off when the boards swell.

Before any paint goes on, a licensed painter will go over the whole surface and scrape off anything that's lifting or flaking. Loose old paint can't hold a new coat: the fresh paint bonds to the old, and if the old is loose, both come off together. Once the loose paint is gone, any bare timber needs a coat of exterior primer before the top coats go on. Bare timber soaks up paint fast and unevenly, so without the primer the finish wears out early.3DuluxView source

Then two proper top coats go on, not one heavy pass.3DuluxView source Two coats gives you even colour and the life you paid for.

If your home was built before 1970, there's one more step before the scraping starts: checking the old layers for lead paint. Old weatherboard homes often have many coats built up over the years, and paint made before 1965 could hold as much as 50 per cent lead.4DCCEEWView source A licensed painter on an older home should confirm the old paint is safe before anyone disturbs it. That is not a DIY job.

If your home also has brick walls, the prep for those is a different job. See the brick painting guide: brick and mortar behave under paint in ways that don't apply to timber.

For render: wait for the cure, clean the haze, fill the cracks

Cement render is a very different surface to timber. It's dense, porous, and highly alkaline when it's new. And it needs time before paint will stick.

New render must cure before painting. The minimum is around 28 days, and a painter will test that the moisture is within a safe range before starting. Paint on wet or green render blisters as the moisture works its way out.5DuluxView source 6TaubmansView source Once the render has cured, there's often a white powdery haze on the surface. That's mineral salts drawn out as the render dried. A painter calls it efflorescence, but the key point is simple: it has to be cleaned off before paint goes on. If paint goes over those salts, it bonds to the salt rather than the render, and as the surface breathes, the salts push the new coat off from behind.

After cleaning, any fine cracks need to be filled. Open cracks let water in, and water behind a paint film always finds a way out, usually by pushing the paint off with it. On bare render that hasn't been coated before, a sealer goes on first so the top coats have something to key into rather than soaking straight in.5DuluxView source

There's one more thing about new render: the high pH. Fresh cement is very alkaline, and oil-based paint reacts with it in a way that breaks the film down. Water-based acrylic doesn't have that problem. That's a practical reason to use water-based on render, not just a product preference.5DuluxView source

The right paint for both surfaces: flexible exterior acrylic, not brittle enamel

For both weatherboard and render, the product is a good exterior water-based acrylic. It dries fast (touch-dry in about 20 to 30 minutes, ready for a second coat in around two hours), is low-odour, has fewer harmful fumes than oil-based paint, doesn't go yellow, and stays flexible as the surface moves with heat.7Dulux TradeView source

That last point is the key one. Weatherboard moves with every hot day and cool night. Oil-based paint starts out with a higher gloss, but it goes harder and more brittle with age. On a surface that moves, a brittle coat cracks at the edges and lifts. A flexible acrylic gives a little with the board. It stays on.7Dulux TradeView source 3DuluxView source

For render, the pH issue above leads to the same choice. Water-based acrylic doesn't react with cement. On textured render, a flexible coat also handles small surface movement better than a hard one.

Finish level is a separate call. Low-sheen is the most common for exterior walls. It shows less surface variation than gloss, which tends to make every small bump stand out.

What drives the cost of painting weatherboard or render

Exterior cladding painting is a live, priced job on SureQuote. It uses the exterior painting service, with pricing built around the surface and what it needs. The number isn't set by which surface you have. It's set by how much prep the surface needs, how high the building is, how many coats go on, and the state of the old paint.

Prep is the biggest driver. A weatherboard wall that just needs a light sand and a recoat is a fast job. One that's lost large areas of paint and needs every bare patch of timber primed is a much longer one. The same goes for render: a painted render wall in good shape is a simple recoat, while new render or render with a lot of salt haze and cracks takes much longer to get ready.

Height adds cost too: a single-storey wall is a different job to a two-storey one that needs scaffold. And two proper top coats cost more than one, but they're also what gives you the life you're paying for. That prep gap is why two quotes for homes of a similar size often look so different. It's almost always the prep, not a pricier brand of paint.

If the job also includes fences or decks, those are a separate surface with their own price. See the fence and deck painting guide for what drives that part of the cost.

What will your exterior painting cost?