An increasingly popular choice of garden building due to their practicality and value for money, metal sheds have over several years rightly earned a reputation for durability.

These reliable outdoor storage solutions range from 5x4ft lean-tos to 10x23ft workshops and garages, and the wide variety of sizes and finishes on offer makes it easy to find the perfect style for your needs. However, there are a few points to consider prior to confirming that a metal shed is a correct purchase for you, including location (distance from the coast) and care precautions (annual treatments), both of which will affect your shed’s appearance and longevity.

What Is Rust?

Rust can develop in a variety of ways, however, it is commonly recognised as either tea staining, a cosmetic concern that sees the surface of the metal begin to discolour and is often controllable, or as localised brown stains, the latter being a much more severe case of rust that often becomes an eyesore and will cause permanent damage to the surface of the metal.

The localised stains may over time begin to impact the structural integrity of the metal, weakening its structure. As layers begin to break away new surfaces are then exposed to the elements, creating a cycle that will eventually break down the structural integrity of the material.

Why Is Sea Air A Problem?

Saltwater is known to increase the process of rust by five times and humidity combined with salt air can see this rusting period double. It is often common for sea air to travel around 30 - 50 miles inland from coastal areas, which should be considered by anyone looking to purchase a metal shed who may not consider themselves to be directly on the coast.

If you are set on purchasing a metal shed we recommend that it is situated in a shaded area that offers an extent of protection from harsh elements, however, be mindful that the structure is not too close to flower beds as plants tend to hold moisture, and that there is plenty of airflow through the building.

Further details can be found in our comprehensive guide on:
Which Metal Shed Should I Buy and Why?

Rusty screws on a metal shed panel.
Screws that have rusted within a panel on a metal garden shed.

Are Metal Sheds Protected From Rust?

Not all metals rust, for example aluminium benefits from an aluminium oxide protective layer that provides a barrier between the metal and moisture and oxygen in the air. There are often different levels of protection dependent on the product’s quality and often fixings are also treated so they are rust-resistant.

For example, our range of BioHort sheds are produced from a ‘hot-dipped galvanised steel plate’ with a zinc coating. Not only are their sheds protected externally, but consideration has also been made in regards to the building’s interior as their side walls and roof panels have a ‘polyamide coating’ and all fixings are produced from a high-quality stainless steel.

If you are looking for something with a bit more value for money, our popular range of Yardmaster sheds are reinforced with 7 layers of protection! They also opt to bake on their colour finish, rather than using a spray method to really lock in all the applied treatments into the metal.

Manufacturers’ guarantees of between 10 - 20 years should provide reassurance regarding their product’s quality and longevity.

How To Maintain Sheds In These Environments

The most common way of maintaining your metal shed if situated in a location exposed to salt water or sea air is regular cleaning.

Simply cleaning the structure with fresh water on a regular basis will remove the corrosive moisture droplets from the metal’s surface. We would advise against the use of any abrasive or acidic cleaners as this may damage the metal’s surface.

We would recommend using a suitable brush and cleaner to treat any areas that appear to be affected by rust.

Clean the surface of the shed and once dry apply a rust-inhibiting primer. Apply two coats allowing each layer to dry. Alternatively, regular applications of a spray grease such as WD-40 or a multi use lubricant will create a barrier between the shed’s surface and any harmful deposits that may stick to the surface.

Although many metal sheds on the market are delivered painted, applying new coats of paint from time to time will not only keep your shed looking clean and new, it will also ensure any marks or scratches that have occurred through general wear and tear are resealed.

Scratches can be a cause for concern with metal sheds as they often expose the primary metal to the elements. Assembling your metal shed on top of cardboard or a soft protective surface will reduce any potential scratches occurring from initial assembly. In some cases, manufacturers often provide ‘touch up paint’ in case of any knocks or scratches occurring during transit or assembly.

“We supply this knowing that some people may scratch their product whilst assembling it as well as their daily use. With this touch-up pen, they can cover up any scratches that they may make.”

To Conclude

It is important to understand that natural weathering processes are often inevitable for metal sheds, however, there are steps that can be taken to improve their longevity. Following all guidance in the assembly manual will also assist with reducing the chances of rust occurring on your metal shed and can often provide further guidance on tips and tricks for annual maintenance.

If you live in an area that suffers from sea air perhaps the only way to be entirely sure that your shed will remain rust-free is to consider another material i.e. plastic, the outstanding choice of sizes and styles that are available ensures that plastic sheds are a viable long term and maintenance-free alternative to their metal equivalents.