Metal pergola - what should you know before choosing a garden or terrace pergola?

A metal pergola is the common name for a garden (terrace) pergola made of steel, cast iron or aluminium. In practice, an aluminium pergola with a slatted roof works best on terraces because it does not rust, is weather-resistant and requires no maintenance. Read what else you should know before you buy.

Metal pergola is a terrace or garden structure made of steel, cast iron or aluminium. It is most often made from powder-coated aluminium profiles, as this solution copes best with the changing climate. In autumn, when there is frequent precipitation, dampness and stronger winds, the choice of material is particularly important. 

What is a metal pergola?

The term 'metal pergola' covers a variety of structures:

• steel - heavy, massive, requiring corrosion protection,
• cast iron - ornamental, used in parks and historic gardens rather than on private terraces,
• aluminium - lightweight, modern, corrosion-resistant and easy to install.

In practice, when someone is looking for a pergola for a terrace, they are usually looking for an aluminium pergola. Aluminium combines aesthetics with functionality and allows large, stable structures to be built that require no maintenance.

Autumn and winter - a test of endurance for pergolas

Autumn and winter are the times when every pergola undergoes a real test of endurance. Frequent rain, dampness on the terrace, falling leaves and stronger gusts of wind mean that the structure must be robust and well protected. It is worth knowing how different metal materials behave in these conditions and why we rely on aluminium pergolas with a lamella roof.

Steel - strong but susceptible to rust

At first glance, a steel pergola appears indestructible. It is a heavy and robust material, but in autumn and winter its weak point is rust. Moisture and lingering water at the foot of the posts quickly take effect if the surface has not been thoroughly protected. Regular painting and inspection of the protective coatings are necessary, and in practice this means extra work and costs.

Cast iron - decorative but not very practical

Cast-iron constructions are mainly found in parks or around historic buildings. On the web, you will mainly find offers for cast iron elements of a more decorative nature. They are elaborately decorated, beautiful, but quite expensive. They look striking, but are not very functional on a private terrace. Because cast iron is heavy, gazebos with cast iron supports require solid foundations. Although cast iron is durable in itself, it needs protection: painting, protective coatings, regular maintenance. Water, ice and frost have a destructive effect, especially where water ponding occurs.

Aluminium - lightweight, resistant, year-round

Aluminium will not rust, crack or require maintenance. The powder-coated profiles retain their colour and smooth surface for years. In autumn, when it rains almost every day, the built-in drainage system is a huge advantage - the water runs off through concealed gutters in the posts instead of flooding the terrace. In winter, on the other hand, aluminium withstands temperature changes well and does not lose its rigidity.

At Otwrane.co.uk we offer aluminium terrace pergolas with lamella roof - The rotating laths can be adjusted to any position. In autumn, you close the roof and protect the terrace from rain, and on warmer days you tilt the slats, letting in light and air.

How much does a pergola cost?

The cost of a metal pergola depends primarily on the material and method of construction. A steel pergola may be cheaper at first glance, but it soon becomes apparent that it requires expensive and regular maintenance. Cast iron is a rare and expensive solution.. A single cast-iron support post is a minimum expenditure of £2.5-3,000. To this must be added the roof structure of the pergola.

Aluminum pergolas can be found in online shops for as little as a few thousand zloty. However, it is worth knowing that these are products based on thinner profiles, less stable and usually sold without professional assembly. In practice, this means that the structure does not always cope well with stronger winds or heavy rain, and the responsibility for correct assembly rests with the customer.

A durable aluminium pergola with lamella roof and installation is an expense from PLN 20,000 to 50,000. The price depends on the dimensions, the colour chosen, the type of roof, the side options (e.g. blinds, glass, panels) and additional equipment such as LED lighting. At Otwrane.co.uk, we price each project individually to match your terrace and expectations.

If you are wondering how the price of an aluminium pergola compares to other solutions, read our guide: Wooden garden pergola - price 2025.

Pergola running costs - steel or aluminium?

At first glance, a steel pergola may be cheaper, but in the long term its maintenance generates costs. Steel exposed to autumn and winter dampness requires regular maintenance - powder coating or refreshing anti-corrosion coatings. Any oversight accelerates rusting, especially at the junctions between the posts and the ground and at the joints of the structure. With larger pergolas, this means recurring expenses and the need to engage professionals, as self-protection is often not enough.

Aluminium works differently. This metal does not rust and does not require any impregnation. The powder coating carried out during the manufacturing process protects the surface of the profiles for years, and the only form of care remains periodic cleaning with water and a mild detergent. There are no costs for refreshing the coating, corrosion protection or replacing components that would deteriorate. In practice, this means that an aluminium pergola is an almost maintenance-free solution - its purchase price quickly balances out with the lack of operating expenses in subsequent seasons.