At MS Gates, we specialise in strong, custom-made steel gates. Based on practical experience with gate construction, automation and long-span cantilever systems, we believe that steel is a much better and safer choice for reliable gate performance.

Aluminium expands more than steel

One of the biggest issues with aluminium is thermal expansion.

All metals expand and contract when the temperature changes. The problem is that aluminium expands significantly more than steel. Typical linear thermal expansion values are around 23 μm/m°C for aluminium and around 12 μm/m°C for steel, meaning aluminium expands almost twice as much as steel under the same temperature change.

For a small object, this may not matter much. But a driveway gate is not a small object.

A cantilever gate can be several metres long. When a long aluminium structure heats up in the sun, even a small amount of movement can become noticeable.

The longer the gate, the more important this becomes.

Why this matters for cantilever gates

A cantilever gate does not run on a track across the driveway. It is supported by a special bottom beam and roller system. This means the whole gate depends on the stiffness and stability of the frame.

If the gate starts to expand, twist or bend slightly, it can affect:

  • Smooth opening and closing.
  • Alignment with the posts.
  • The roller system.
  • Automation performance.
  • Long-term reliability.

This is why material stability is so important. A cantilever gate needs to stay straight and rigid, not only when it is new, but after years of weather, sun exposure and daily use.

Sun exposure can heat one side more than the other

Another practical issue is uneven heating.

A gate is often exposed to direct sunlight from one side. One side of the gate can become much warmer than the other. When that happens, the material may expand unevenly.

With a long aluminium gate, this can increase the risk of visible movement, bowing or twisting. Even if the change is small, it can still be enough to affect how the gate runs.

For a cantilever sliding gate, small changes can create big problems because the system relies on precise balance and alignment.

Aluminium is less stiff than steel

Aluminium is lightweight, but that does not automatically make it better.

Steel is much stiffer than aluminium. In general engineering terms, aluminium has roughly one third of the modulus of elasticity of steel, which means that for a similar shape and size, aluminium will deflect more under load.

In simple words: steel holds its shape better.

For gates, this matters a lot. A driveway gate is not just a decorative panel. It is a large moving structure. It needs strength, stiffness and stability.

Corrosion resistance is not the whole story

One of the main arguments for aluminium gates is that aluminium does not rust like steel. That is true, but it does not mean aluminium is automatically the better material.

A gate must do more than resist corrosion. It must remain straight, stable and reliable. For cantilever gates, stiffness and structural stability are often more important than weight.

A properly made and properly finished steel gate offers excellent durability, while also giving the structure the strength and rigidity needed for long-term performance.

Steel vs aluminium at a glance

✓ Steel (what we use)

  • Excellent rigidity
  • Holds shape under load
  • Lower thermal expansion
  • Stable in direct sunlight
  • Predictable long-term performance
  • Anti-corrosion coatings available

✗ Aluminium (why we avoid it)

  • ~⅓ the stiffness of steel
  • ~2× more thermal expansion
  • Can bow or twist in sunlight
  • Less rigid over long spans
  • Movement affects alignment
  • Corrosion resistance not enough alone

Why MS Gates chooses steel

At MS Gates, we do not recommend aluminium gates because we believe they are not the best option for strong, long-lasting driveway gates.

We choose steel because it offers:

  • Better rigidity.
  • Better structural stability.
  • Better performance for cantilever systems.
  • Better suitability for larger and longer gates.
  • Stronger construction for daily use.

For us, a gate should not only look good on the day of installation. It should work smoothly and reliably for years.

Material is just one of many design decisions — for the full picture, see our article on why a sliding gate is an engineered system.

Our honest opinion

Aluminium may be suitable for some lightweight products, but for custom-made driveway gates — especially cantilever sliding gates — we believe steel is the better choice.

If you are looking for a strong, made-to-measure gate, MS Gates recommends a properly built steel gate rather than an aluminium one.

A gate is a long-term investment. The material matters.

If you're weighing up cantilever vs tracked sliding gates as well, our comparison guide covers the practical differences.