Aluminium vs Timber vs Steel Windows:
What's Best for a Cape Town Home?

Replacing windows is a big decision, and the material question comes up early in almost every conversation we have with homeowners. Timber has heritage charm. Steel has an industrial edge that’s having a real moment in design circles. Aluminium is what we fabricate and install every day — so rather than just tell you “aluminium is best,” here’s an honest breakdown of how the three compare for a Cape Town home specifically.

Coastal climate: the deciding factor

Cape Town’s proximity to the coast means salt air, humidity, and UV exposure are constant factors — and they affect each material very differently.

Timber is a natural insulator and has genuine aesthetic appeal, particularly for period homes in areas like Observatory or the Southern Suburbs. But timber is vulnerable to swelling, warping, and rot in humid coastal conditions, and requires regular sanding, sealing, and repainting to stay weather-tight — an ongoing cost many homeowners underestimate.

Steel windows have surged back into fashion for their slim sightlines and industrial-loft aesthetic. However, untreated or poorly maintained steel is highly susceptible to corrosion in salt air, and once rust sets in around hinges and frames, repairs are costly. Galvanised and powder-coated steel mitigates this, but adds to the price.

Aluminium is naturally corrosion-resistant — it doesn’t rust, and powder-coated or anodised finishes hold up well against salt air and UV exposure with minimal maintenance beyond an occasional wipe-down with mild soapy water.

Maintenance, realistically

If you want a “fit and forget” window, aluminium wins by a clear margin. Timber needs the most ongoing attention — repainting every few years is standard, more often in harsher coastal-facing positions. Steel sits in the middle: well-coated steel can go years without issue, but any chip or scratch in the coating becomes a corrosion starting point if left untreated.

Not sure which material suits your home? We’ll give you a straight answer — even if that means pointing you toward a different solution.

Cost comparison

Aluminium typically sits in the middle of the three on upfront price — generally less expensive than premium timber or custom steel, while offering a longer maintenance-free lifespan than either. Timber can be cost-competitive initially but accumulates maintenance costs over its life. Custom steel framing tends to be the most expensive option, particularly for larger openings, due to fabrication complexity.

Lifespan

With proper care, aluminium windows commonly last 20+ years without structural degradation. Timber’s lifespan depends heavily on maintenance discipline — a well-maintained timber frame can last decades, but neglect shortens that significantly. Steel, properly coated and maintained, can also last decades, but is more sensitive to coastal conditions than aluminium if maintenance lapses.

Style: the myth that aluminium is "industrial only"

A common misconception is that aluminium only suits modern or industrial-style homes. In reality, modern aluminium profiles are available in a wide range of finishes — including woodgrain-effect powder coating that mimics timber’s warmth, and slim sightline profiles that rival steel’s minimalist look — making it a realistic option for period homes, contemporary builds, and everything in between.

Our honest take

We fabricate and install aluminium because we believe it offers the best long-term value for Cape Town’s specific coastal conditions — corrosion resistance, low maintenance, and durability without the ongoing cost of timber upkeep or the corrosion risk of untreated steel. That said, the right material always depends on your home’s architecture, heritage status (if applicable), and budget.