Types of Sign Posts: Comparing Materials and Applications

Aluminium Sign Posts

Aluminium sign posts are lightweight yet strong supports made from high-grade aluminium, giving them an excellent strength-to-weight ratio. They are naturally resistant to corrosion and typically come with a durable powder-coated finish for a sleek, professional appearance. Powder coating (in common colours like black, white, grey, or even Decro wood-grain effects) provides a premium look and long-lasting surface protection. These posts are available in a wide range of sizes – usually up to 6000 mm in length – with circular profiles from around 50 mm diameter up to ~127 mm, and square profiles from about 50 mm to ~150 mm. This variety allows matching post size to the sign’s dimensions and visibility needs.

Common Applications: Aluminium posts are popular for business premises signage, wayfinding signs, school and campus signage, and hospitality sector signs where appearance matters. They are often used on private property, business parks, car parks and other non-highway locations, offering an attractive finish when the style is as important as function. Wood-effect Decro coatings can even be applied to give the modern aluminium post a natural timber look for aesthetic integration into certain environments.

Strength and Limitations: While not as strong as steel, aluminium posts generally provide sufficient strength for most standard installations when properly engineered for wind loading and sign size. In practice, aluminium posts can reliably support signage in UK conditions, so long as the correct profile is selected based on calculated loads. Aluminium’s lighter weight makes handling, transport and installation much easier than steel. It is also highly recyclable and considered a more sustainable choice long-term. Overall, aluminium sign posts offer a blend of adequate strength, low weight, corrosion resistance and premium finish, making them a go-to option for local signage where a balance of performance and appearance is desired.

Steel Sign Posts (CHS Supports)

Steel sign posts – often in the form of circular hollow section (CHS) steel tubes – are the traditional choice for demanding or structural applications. Steel is extremely strong and robust, making these posts suitable for large signage and harsh environments (such as high-wind areas and major roads) where maximum strength and rigidity are needed. Standard galvanized steel posts are very durable and can support large sign installations. They are usually hot-dip galvanised to prevent rust, giving a silvery grey appearance. Optionally, they can be powder-coated or painted for improved aesthetics or to match branding.

Sizes and Specifications: Steel posts are available in lengths up to around 7.5 metres (7500 mm). Common diameters include 60 mm, 76.2 mm, 88.9 mm, 114 mm, 140 mm and larger. The 76 mm diameter steel post is an industry-standard for smaller roadside signs and parking signs, providing a good balance of strength and manageability. Steel posts are significantly heavier than aluminium ones, which means transportation and manual handling require more effort. Installation often involves concreting the post into the ground, and accessories like baseplates are used to secure the post and prevent rotation in the footing.

Strength and Safety: In terms of load-bearing capacity, steel posts excel. This makes them ideal for highway signage, large directional signs, and other structural sign applications. A standard steel post can pose a serious hazard to vehicles if struck at high speed. 76 mm galvanised steel posts are considered passively safe under BS EN 12767, meaning they will bend or shear off when hit by a vehicle. Larger diameter steel posts are not inherently passively safe and may not be suitable near high-speed roads unless additional safety measures are in place.

Applications: Steel posts are commonly used by highways agencies and councils for road traffic signs, motorway signage, large informational boards, and any installations where structural integrity is paramount. They are also used in public areas prone to vandalism or impact. Steel sign posts offer maximum strength and durability, with the trade-off of higher weight and a need to consider impact safety on high-speed routes.

Passively Safe Sign Supports

Passively safe sign supports are a special category of posts designed to minimise injury to vehicle occupants and damage to vehicles in the event of a collision. Unlike conventional rigid posts, passive-safe supports will either absorb crash energy or cleanly break away when struck. These supports are intended for use on high-speed roads or other locations where an out-of-control vehicle might collide with the sign post.

Design and Standards: Passive-safe sign posts come in various designs and materials, including engineered steel couplings, aluminum frangible masts, and composite posts. All must meet the requirements of BS EN 12767. Some designs are non-energy-absorbing (NE), while others are energy-absorbing (HE). The choice depends on road context: NE posts are often preferred on high-speed roads, whereas HE posts might be used in lower-speed urban areas.

Examples of Passive-Safe Systems: The UK market includes several passive-safe systems such as Jerol, Lattix, Optimast, Tecnopali, Contipole, and Kapu. Each meets BS EN 12767 and is designed for compatibility with UK highway signage. Passive-safe sign supports provide a safety-optimised solution for roadside signage, ensuring compliance with modern road safety standards and reducing the likelihood of severe injuries in accidents.

Recycled Plastic Sign Posts

Recycled plastic sign posts are an eco-friendly option for smaller signage needs. These posts are made from 100% recycled plastics, resulting in a product that is highly resistant to rot, rust, and water damage. They are UV-stabilised to resist sun damage, making them durable and weatherproof in outdoor conditions. They require little to no maintenance.

Suitable Applications: Recycled plastic posts are generally used for smaller signs and low-load applications such as road name plates, footpath and trail markers, and park informational signs. Their plain and functional appearance can be adequate for utility signage and blends well into natural or rural settings.

Strength and Limitations: Recycled plastic is not as rigid as metal; it can flex under load. In hot weather, plastic posts may soften slightly, and they are subject to thermal expansion and contraction, which may loosen fixings over time. They are best used for lightweight signs where high structural performance is not required.

Environmental Impact: These posts help divert plastic waste from landfills and reduce the demand for raw materials. They also eliminate the need for chemical treatments or galvanizing processes.

Comparison Table