Painting by Cladding Type: Weatherboard, Plaster, Brick and Fibre Cement

Exterior painting is often discussed as though a house is a single surface. It rarely is. Most Wellington homes carry at least two cladding types, and each one wants different preparation, different products and sometimes a different answer to whether it should be painted at all.

Timber weatherboard

The most common cladding on older Wellington homes, and the most forgiving to repaint, but the one that most rewards thorough preparation.

Timber moves with moisture and temperature, so the coating has to move with it. That means a flexible system rather than a hard, brittle one, and it means the gaps and joints matter as much as the faces. Expect scraping back to sound material, feathering the edges, filling, replacing failed putty in the joinery, and priming every bare patch before the finish coats.

Watch the bottom edges of the boards and anywhere near the ground. Splashback and poor drainage cause most of the rot we find.

Plaster and stucco

Solid plaster and stucco are common on Wellington homes from the 1930s onward and on many later ones. The surface is porous and it cracks, which is normal, but the cracks need judging rather than simply filling.

Fine hairline crazing is usually cosmetic and can be bridged with the right system. Cracks that are wider, that run in a line, or that have staining around them can indicate movement or water getting behind the cladding, and painting over those hides a problem rather than solving it.

Plaster generally wants a breathable coating so trapped moisture can escape. Sealing a damp plaster wall with an impermeable film is a reliable way to cause blistering.

Monolithic and textured plaster systems have their own considerations, and we have written separately about monolithic homes.

Fibre cement

Fibre cement sheet and weatherboard is stable, does not rot and takes paint well, which makes it straightforward. The two things that matter are sealing any cut edges, which are porous and are a common entry point for moisture, and using a primer suited to the material rather than a timber primer.

Older fibre cement is a different matter. Sheet products from before the mid-1980s may contain asbestos, and cutting, sanding or water-blasting them is not something to do casually. If your house is of that era and the cladding is fibre cement sheet, it is worth establishing what it is before any preparation starts.

Brick

The first question with brick is whether to paint it at all. Sound, well-laid brick does not need paint, and painting it is close to irreversible. Removing paint from brick later is difficult, expensive and often damages the face of the bricks.

If brick is being painted, usually because it has been painted before or because the appearance is genuinely poor, it needs a breathable coating. Brick and mortar carry moisture, and an impermeable film traps it, which leads to peeling and can push salts to the surface. Repointing any failed mortar comes first.

Metal: spouting, downpipes, garage doors and roofing

Metal wants a different approach again. Galvanised surfaces need an etch or a specific primer, because standard paints do not adhere well to them. Rust must be dealt with properly rather than coated over.

Roofing is a specialist job in its own right and depends heavily on the material. We cover that separately under roof painting.

Where two claddings meet

The junctions are the vulnerable points on any mixed-cladding house. Different materials move at different rates, so the sealant at those junctions works harder and fails sooner. Any competent repaint should treat those lines as a specific item rather than something to run a brush past.

Getting the specification right for your house

A quote for a mixed-cladding home should name the preparation and products for each surface type rather than treating the exterior as one item. If you would like that written out for your property, get in touch, or read more about our exterior house painting work.