External Painting And When To Repaint

Repainting the outside of a building looks like a cosmetic decision made when it starts to look tired.

It is a maintenance decision, and the reason is that the paint is protecting the material underneath from water and ultraviolet light. Once the coating fails, the substrate starts taking damage, and the cost changes category.

What decides the interval

Not a fixed number of years. The exposure.

Orientation. North and west facing walls take the most sun and fail first. A building repainted all over on the same cycle will have surfaces at very different stages.

Coastal exposure. Salt accelerates coating breakdown and corrodes any exposed metal. Buildings near the water need a shorter cycle and better systems.

Substrate. Rendered masonry, fibre cement, timber and metal all behave differently. Timber is the most demanding, because it moves and because water reaching it causes rot rather than just staining.

The previous system. What was used last time, whether it was compatible, and whether the preparation was done properly. A cheap repaint over poor preparation fails in a few years regardless of the product.

As a general shape, expect a shorter cycle on timber and on exposed elevations, and longer on protected rendered surfaces.

The signs it is due

Chalking. Rub a hand on the surface and it comes away with a powdery residue. The binder has broken down.

Fading and loss of gloss, particularly noticeable when you compare a sheltered section to an exposed one.

Hairline cracking or checking in the coating film.

Peeling or flaking, which means adhesion has already failed and water is likely behind the film.

Exposed substrate anywhere. This is past due, not approaching due.

Rust bleeding from any metal element, which means the coating on that element failed some time ago.

Why late costs more

Once the coating stops protecting, the substrate takes the damage.

Timber absorbs water and rots, and rot means replacing boards rather than painting them. Render cracks and delaminates. Fibre cement takes water at the edges and swells. Metal corrodes, and corrosion has to be removed back to sound material before anything can be applied.

So a repaint that was a preparation and coating job becomes a repair job with a coating on top, and the repair is the larger cost.

Preparation is most of the work

The coating is a small part of an external repaint. The preparation is the job.

Washing to remove dirt, salt and any biological growth. Scraping and sanding back failed coating to a sound edge. Repairing cracks, replacing damaged material, and treating any rust back to bare metal. Priming and sealing the repairs and any bare substrate.

A quote that is substantially cheaper than the others has almost always saved the money here, and it will show within a few years.

Access decides a large part of the cost

On a multi-storey building, the access method is often the single largest line.

Scaffold, swing stage, rope access or elevated work platform. Each has different costs and different implications for the programme and for residents.

This is also why doing everything at once makes sense. If the scaffold is up, do the gutters, the balustrades, the window seals and any repairs at the same time, because the access is the expensive part and it is already paid for.

In a strata building

External painting is common property, it is usually the largest single item in a capital works plan, and it needs a clear scope so quotes can be compared.

A scope that specifies the preparation standard, the coating system and the number of coats produces comparable prices. A scope that says repaint the building does not.

The order that works

Assess, repair, then paint. Any water entry, any cracking that is letting water in, any rot or corrosion is fixed first.

Painting over an unresolved water problem hides it until the coating fails again, faster than last time.

We handle the assessment, the repairs and the coating as one job across building, carpentry and painting. Get the assessment done before the next capital works cycle.