Flagpole materials in New Zealand: aluminium, fibreglass, steel or timber?

The material of a flagpole decides how it copes with New Zealand conditions: strong UV, salt spray along a long coastline, and wind that funnels through gorges and over ridges. Most poles sold in New Zealand are aluminium, but fibreglass, steel and timber each have their place. The Building Act 2004 requires all building work to comply with the Building Code, which includes structure and durability, whether or not a building consent is needed.

Aluminium

New Zealand flag makers use marine-grade aluminium. The Flag & Banner Company makes its conventional flagpoles with all marine-grade components and supplies them powder-coated white as stock, with other powder-coat colours or anodising to marine specifications as extras. Flagmakers describes its poles as powder-coated marine-grade aluminium designed for “NZ’s harsh environment”. According to the Flag & Banner Company, mill-finish aluminium without some coating will turn black with weathering. Aluminium is light, which makes transport and installation easier, and it does not rust.

Fibreglass

Fibreglass poles are light and flexible, and they do not corrode. They bend in strong wind rather than holding rigid, and their surface can become chalky after long exposure to sun. Fibreglass conducts less electricity than metal when dry, but this does not make it safe near power lines: WorkSafe’s minimum approach distances to overhead lines apply to tools and equipment of any material, as described in the guide to flagpole safety.

Steel

Steel poles are used where height and load call for it, such as tall poles at stadiums, ports and public buildings. Steel is strong but heavy, which affects delivery, the crane needed to lift the pole and the size of the footing, and it needs galvanising or coating against rust. Flagmakers’ aluminium poles stand in a heavy galvanised steel ground tube, a common combination.

Timber

Timber was the traditional material for flagpoles and flag masts, including the flagstaffs of the 19th century described in the guide to flagpole history. Today it is used mainly at heritage sites and for indoor ceremonial poles. Timber needs regular painting or oiling and checks for rot at the base, where the pole meets the ground.

Comparison

Sea spray and wind

• Sea spray: under NZS 3604, the standard for timber-framed buildings, New Zealand is divided into exposure zones according to the risk of wind-driven sea spray, and BRANZ Maps shows the zone for each site, according to BRANZ. Metal parts corrode faster near the sea, and steel fittings on an aluminium pole can corrode where the two metals meet.
• Wind: NZS 3604 also classifies sites into wind zones from low, below 32 m/s, to extra high, 55 m/s, and sites above that need specific design, according to BRANZ. Landforms create lee zones with locally higher wind speeds. A flagpole on an exposed site is designed for these loads.
• Sun: strong UV weakens finishes, halyards and flags; more in the guide to flagpole lifespan.

Finish and fittings

The pole’s finish is only part of the picture: the truck, pulley, cleat and halyard wear at their own pace. Flagmakers uses a cast aluminium truck on its poles. An overview is in the guide to flagpole accessories, and upkeep in the guide to flagpole maintenance. The types of poles are described in the guide to types of flagpoles.