Anodising vs Powder Coating: Choosing the Right Finish for Aluminium

Anodising vs Powder Coating Aluminium: What’s the right choice? 

When specifying aluminium building products, the finish is about more than colour. The right choice can affect appearance, maintenance, durability and how a product performs in its environment.

Two of the most widely used finishes for architectural aluminium are anodising and architectural polyester powder coating. Both have their advantages, but they achieve very different results.

At Dales, we manufacture a variety of aluminium building goods including Gutters, Fascias, Soffits, Copings, Solar Shading, and bespoke architectural features in both finishes. So, rather than simply offering a colour chart, we can help you choose a finish that works for the building, the location and the specification.

What is anodising?

Anodising is an electrochemical process that enhances the natural oxide layer on the surface of the aluminium. Unlike a paint finish, the anodised layer becomes part of the aluminium itself. This gives the surface its distinctive metallic appearance and helps provide a durable, low-maintenance finish.

Anodised aluminium has excellent resistance to UV exposure, reducing levels of UV fade, making it particularly suitable for demanding environments and locations with high levels of sunlight, including coastal areas.

Dales Fascia Soffit at Victoria Gate, Worthing finished in UA 150-0

There can also be variations in tone and shading between individual components. That variation isn’t a fault. It is a characteristic of anodised aluminium and is part of its appeal – similar to the variation seen in natural materials like stone, timber or slate. It does mean, however, that if a completely uniform colour is required across every component, anodising may not be the best choice.

What is powder coating?

Architectural polyester powder coating provides a different approach. The aluminium is pre-treated before a dry powder coating is electrostatically applied and cured to form a tough, protective finish.

One of the biggest advantages of powder coating is choice. Powder coating offers an extensive range of RAL and BS colours, metallic finishes, different gloss levels and specialist effects. It can therefore be a practical option where a consistent colour is important or where the aluminium needs to coordinate closely with other elements of the building.

Magpas Air Ambulance base featuring fascia soffit powder coated in RAL 2003 to match their distinctive logo

At Dales, our second Ilkeston factory houses a Syntha Pulvin Approved Applicator facility, where we use Syntha Pulvin architectural polyester powder coatings. We can also supply products in other recognised architectural powder coating systems, using the relevant manufacturer’s approved applicator where required.

Anodising vs Powder Coating

Which finish is right for your project?

There isn’t one answer that suits every building.

Dales offers architectural powder coating for aluminium, alongside anodised finishes, to suit a range of project requirements.

Consider anodising where:

• The project is in a high-UV, coastal or demanding environment.
• A natural metallic appearance is part of the design.
• Subtle variation between components is acceptable, or desired.
• Long-term appearance and low maintenance are priorities.
• The specification calls for an anodised finish.

Dales offers anodised aluminium in a range of colours and finishes, giving architects and designers plenty of scope beyond the traditional silver appearance.

Consider powder coating where:

• A consistent colour across the installation is important.
• The aluminium needs to match another building element.
• A particular RAL or BS colour is required.
• A specialist or textured appearance is wanted.
• The project requires bespoke components in relatively small production runs.

Powder coating can also provide a practical alternative to the appearance of anodised aluminium. Anodite powder coatings, for example, are designed to give an anodised-style appearance at a lower cost.

Location matters

The location of a building is a very important consideration when selecting a finish. Coastal and marine environments can be particularly demanding. Salt and moisture can accelerate corrosion and the specification may need to be adapted accordingly.

Coastal environments can accelerate corrosion, making the right aluminium finish essential for long-term durability.

A basic marine-grade powder coating specification using QualiCoat Class 1 on all sides of the aluminium is usually suitable, while QualiCoat Class 2 may be considered for more extreme environments, and depending on the project’s budget and colour requirements.

Guarantees are also dependent on factors including location, environment and the finish specified, so it is worth establishing these requirements early in the design process. If you’re working on a coastal or particularly exposed project i.e. within 2km of the sea or tidal estuary, speak to the Dales team before finalising the finish.

What about fire performance?

Reaction to fire should always be considered when specifying aluminium finishes, particularly for products forming part of the building envelope. Dales manufactures products in plain aluminium, anodised aluminium and architectural polyester powder-coated finishes. Aluminium and anodised aluminium are classified as non-combustible.

Dales uses architectural polyester powder coatings from major manufacturers including Syntha Pulvin (Sherwin Williams), Interpon D (Akzo Nobel), Drylac (Tiger), Axalta and Powdertech. These architectural polyester powder coatings are independently tested to BS EN 13501-1:2018 and achieve A2-s1,d0 classification, indicating limited contribution to fire (A2), very limited smoke production (s1) and no flaming droplets or particles (d0).

Dales has also undertaken independent testing with Warrington Fire, confirming an A2-s1,d0 classification for an architectural powder-coated Dales system. Independent test classification certificates are available where required. As fire performance relates to the specific product and application, the relevant classification should always be checked as part of the specification.

Finish selection is easier with the right information

​Dales offers Syntha Pulvin architectural powder coatings in a wide choice of colours and finishes for aluminium products.

Dales can provide advice on finish selection, technical details and specification requirements, alongside our wider design support service. Our in-house technical team can also help with 2D DWG and PDF details, NBS specification clauses, product information and project-specific advice.

Need to compare finishes?

Take a look at our Colours & Finishes range to explore the available options and request physical colour samples. Or, if you’re already working on a project, send us your drawings and our design team can help you work through the practical details.

In Conclusion:

Anodising and powder coating both have a place in architectural aluminium. Anodising offers a distinctive metallic appearance, excellent UV resistance and natural variation, making it particularly suited to projects where the finish itself is part of the architectural aesthetic.

Powder coating provides a huge choice of colours and effects, a more uniform appearance and considerable flexibility for bespoke applications. The important thing is to select the finish based on the building, environment, appearance, performance requirements and budget – not simply the colour.

And if you’re not sure which one is right, that’s where Dales can help. With manufacturing and powder coating facilities in Ilkeston, an in-house design and technical team, and experience supplying everything from standard rainwater systems to bespoke architectural aluminium, we can help you get the finish right before the order reaches the factory.