Coastal Considerations: Metal Gutters and Roofline

Metal guttering and roofline can be susceptible to increased degradation in coastal areas due to the salty air and minerals in the environment, which can eat away at metals over a prolonged period of time. There are however, a few steps you can follow and choices you can make for your building materials if you're in a coastal area in order to make the most out of your gutters and roofline.

COPPER GUTTER AND ROOFLINE

Copper is actually a great option to use in coastal areas. Thanks to the patina layer copper develops over time, it can actually provide more resistance to salty and mineral-filled coastal air than a lot of other gutter materials! Our range of copper gutter boasts a 100-year life expectancy and resistance to corrosion in virtually any atmosphere, as once this chemical reaction has occurred, any salt deposits the metal comes into contact with will not be able to attach to the structure.

ZINC GUTTER & ROOFLINE

Zinc gutter products also benefit from the patina effect that can help prevent corrosion and degradation in coastal areas. It's slightly more susceptible to degradation in coastal areas than copper, but this can be managed effectively with ongoing maintenance and cleaning. Zinc is more susceptible when salts sit on its surface for prolonged periods of time - if in your area it is regularly raining or you're able to rinse off your roofing and soffits relatively frequently, you won't find corrosion to be a problem.

CAST IRON GUTTER

When it comes to cast iron gutters, variations in the environment can affect the longevity of any of the paint coatings. Although Hargreaves cast iron gutters are supplied with at minimum a transit primer coat that is anti-corrosive, we would always recommend opting for their preimer coastal paint option instead of any regular paint job. This specifically applies if you are within 5km of the sea, as the paint has been developed in response to the rigours of a marine environment - one that can have an effect on the paint work quality of any surface.

Although the 100-year life expectancy will not apply to cast iron gutters installed in coastal and marine areas, it's far more likely that your gutter system will outlive this when the premier coastal paint option is combined with regular maintenance and repairs at the first sign of rusting.

ALUMINIUM GUTTER AND ROOFLINE

Aluminium can be susceptible to corrosion in coastal areas for a number of reasons. Salt from seawater or the air can break down the oxide film that protects it, either through direct contact with waves or air carrying the salt inland. Although our ARP aluminium gutters and aluminium roofline are corrosion-resistant, they are not corrosion-proof - however, increased maintenance can help prolong the life expectancy and aesthetics of your aluminium products.

This handy table provides a guide to coastal areas and the frequency of cleaning your aluminium systems might need, depending on how close to the coast you are. We recommend adhering to the following guidelines:

ENVIRONMENT	DISTANCE FROM COASTLINE/POLLUTION	CLEANING FREQUENCY
Normal - C3 Inland	Greater than 5km	12 months
Marine - C4 Coastal	Between 2km and 5km	12 months
	Between 500m and 2km	6 months
	Between 50m and 500m	3 months
	Less than 50m	Contact ARP for advice
Industrial  - C5I	Between 2km and 5km	12 months
	Between 500m and 2km	6 months
	Between 50m and 500m	3 months
	Less than 50m	Contact ARP for advice
Swimming Pool	Greater than 2m from edge of pool	3 months
	2m from edge of pool	Contact ARP for advice

STEEL GUTTERS

The mass loss properties of zinc coatings and their corrosion resistance are similar for coloured and galvanised guttering systems when considering the raw zinc layer. However, black, copper effect and graphite steel gutter options have a mill color coating, which gives them a longer lifespan than regular galvanised steel gutters. Galvanised systems, on the other hand, have an extra polymer coating, providing additional durability compared to regular galvanised steel.

Black, graphite and copper effect steel gutters are protected by a layer of zinc passivation to enable them to claim greater resistance against corrosion. This isn't permanent resistance though, and the table below demonstrates how much mass and thickness your steel gutter system could lose per year of exposure in different environments.

Luckily, there are a few steps that can be taken to minimise any corrosion loss, such as ensuring any scrapes or dents are painted using the touch-up pen, to give an added layer of resistance against the elements. It is also crucial to ensure your gutters are cleaned frequently to reduce any buildup that could affect the integrity of the gutter system

CORROSIVITY CLASS	CORROSIVITY	EXAMPLES OF ENVIRONMENT		MASS LOSS PER SURFACE UNIT/THICKNESS LOSS (AFTER 1ST YEAR OF EXPOSURE)
		EXTERIOR	INTERIOR	MASS LOSS G/M3	THICKNESS LOSS UM
C1	Very Low	N/A	Heated buildings with clean atmosphere, e.g. offices, shops, schools, hotels	> 0.7	>0.1
C2	Low	Atmospheres with a low level of pollution: mostly rural areas	Unheated buildings where condensation can occur, e.g. depots, sports halls	>0.7-5	>0.1-0.7
C3	Medium	Urban and industrial atmospheres, moderate sulfur dioxide pollution; coastal areas with low salinity	Production rooms with high humidity and some air pollution, e.g. food-processing plants, laundries, breweries, dairies	>5-15	>0.7-2.1
C4	High	High Industrial areas and coastal areas with moderate salinity	Chemical plants, swimming pools, coastal ship and boatyards	>15-30	>2.1-4.2
C5	Very High	Industrial areas with high humidity and aggressive atmosphere and coastal areas with high salinity	Buildings or areas with almost permanent condensation and with high pollution	>30-60	>4.2-8.4
CX	Extreme	Offshore areas with high salinity and industrial areas with extreme humidity and aggressive atmosphere and subtropical and tropical atmospheres.	Industrial areas with extreme humidity and aggressive atmosphere.	>60-180	>8.4-25