How to maintain your garden shed

How to maintain your garden shed

Lucas, Antique wood-worker, Gloucester

Guide written by:

Lucas, Antique wood-worker, Gloucester

28 guides

Before applying any paint or varnish to your garden shed, it must be cleaned, sanded and primed. Rustproof protection is available for metal sheds while wooden sheds should be coated with an insect- or fungi-repellent. Read on for more care tips to help extend the service life of your shed!

Important features

  • Material
  • Paint
  • Stain
  • Varnish
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Metal is a great material for garden sheds provided you are thorough when it comes to maintenance. As sheds are constantly exposed to the elements a metal shed that has not been properly cared for will have a very limited lifespan.

This is due to the natural properties of the material. Firstly, the appearance of the metal will begin to deteriorate, then will rust set in and start to weaken the structure. It is, of course, possible to re-coat your shed with a special metal paint but regular cleaning is a much simpler and cheaper option.

How to clean your metal shed

Garden sheds come in all different types of metal including aluminium, iron, stainless steel, and galvanised or non-galvanised steel. While a layer of protective paint can help to improve your shed’s defences, you must be careful not to soak the shed and avoid using large quantities of water.

The most effective and least risky cleaning solution is a good old-fashioned bucket of soapy water. You simply have to scrub the shed using a non-abrasive sponge, making sure to wring it out as you go. Using a hose is not out of the question but this option should be reserved for warmer weather.

Products for cleaning metal sheds

There are many cleaning products on the market that have been specially designed for metal garden sheds. As a general rule, you should go for a gentle and environmentally friendly option, although washing up liquid is usually enough to do the trick!

In terms of tools, a sponge is really all you need but a hard bristle brush or iron wool can also be used to remove small patches of stubborn rust.

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Cleaning products

Composites are ideal for garden sheds. Easy to clean and rot-proof, they do not usually require any protective treatment. The only downside to composite sheds is that they can fade due to prolonged UV exposure.

How to clean your composite shed

These sheds can be washed using a low-pressure water hose or a sponge and soapy water. Simply wipe off any dirt and rinse with clean water (if using soap).

Always follow the manufacturer’s instructions carefully when applying specialist composite cleaners.

Specialist composite shed cleaners

Specialist cleaning products for composite materials are available and these may be concentrated or non-concentrated. The advantage of using these products is that they are able to thoroughly clean your shed and restore its original shine or at the very least help to revive its colour.

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Wooden sheds require regular maintenance. In addition to being exposed to the rain and UV rays, they are also a tempting prospect to wood-destroying insects!

As such, wooden sheds can rarely be left untreated and must be coated with anti-woodworm treatment as a bare minimum (whether this be in the form of a wood stainvarnish or wood paint). However, these protective layers do not last forever and you will find yourself having to apply additional wood care products before long.

Some garden sheds may not require treatment as their wood has been high-temperature heat treated (HTT) or treated in an autoclave (an impregnation process based on pressure). Certain other woods, including various exotic species, are naturally rot-proof but these will still require an exotic wood oil finish.

How to clean your wooden shed

How you clean your wooden shed will ultimately depend on the kind of protective coating that has been applied. Garden sheds that have been stained can be cleaned with a nylon brush, as the stain penetrates deep into the wood and does not form a protective outer layer such as that created by paint or varnish.

A garden shed painted with wood paint can be cleaned using a bucket of water and a sponge. Soapy water can also be used and, ideally, you should use an environmentally friendly soap. For stubborn stains you can use the abrasive side of the sponge but be sure to apply light pressure in order to avoid scratching or damaging the paint.

If you want to remove the current treatment (be it a stain, paint or varnish) simply apply a wood brightener. This will penetrate deep into the wood, removing the protective layers completely. A stripper can also be used before applying paint or varnish.

Products for cleaning wooden sheds

When it comes to maintaining a wooden garden shed, it's difficult to recommend a specific product as there is such a wide range of options (nylon brushesclothssoapy water, etc.). You can even use wood soap and warm water to bring out the shine of stained wood. However, this treatment is not suitable for painted wood.

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Paint strippers

After taking care to remove all dirt, the first step to repainting your metal garden shed is to sand it. The aim here is to remove as much of the old paint as possible, buffing out any scuffs and imperfections, and creating a fresh base for paint to adhere to. A couple of run-throughs with 120- then 180-grit sandpaper should be ideal. Depending on the surface, you can either use an electric sander or sand the whole thing by hand.

If your shelter has rust marks, go over them with a wire brush or iron wool and then proceed to sanding. Do not forget to wear protective gloves! Next, apply an undercoat of special outdoor primer: it will effectively protect your shed and make it easier to paint later on.

To finish, apply two coats of a suitable paint containing a rust inhibitor and your metal garden shed will be as good as new! For repainting, you’ll need a set of brushes, a protective mask to protect you from VOCs (Volatile Organic Compounds) and a few other essential painting tools.

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Wire brushes

There are several possible treatments designed to protect, stain or dye wooden garden sheds. You have a number of options depending on the desired result and the initial treatment of the wood.

Preparing the wooden shed

Before applying anything, sand down your garden shed several times in order to remove the old outer layers and create an even surface. Feel free to use a cleaner or brightener, if required.

Fungi and insect repellent

Treatments against fungi and insects tend to be long-lasting and are essential for ensuring the durability of your wood. If you are fully renovating your garden shed, this treatment should be carried out before the application of varnish or paint. Remember that the majority of varnishes also offer some degree of fungal treatment, insect repellent or wood colouring.

Wood brighteners

Wood brighteners are designed to give the wood back its original colour and should be applied before a stain or varnish. Wood tends to grey over time and with exposure to UV rays. This product should be applied with a brush and a protective mask should always be worn.

Penetrating wood oils

Oils, stains, varnishes and wood paints are so-called finishing products, meaning they are applied last. Penetrating oils work by fully penetrating the wood.

Final preparations

Finally, after lightly dusting the surface, you can apply your selected paint, making sure to follow the direction of the grain. Use a paint brush or roller to apply the recommended number of layers and be sure to take note of drying times.

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Penetrating oils

The main difference between wood paints and stains is that paint creates a film over the wood while stains are non-film-forming, microporous and water-repellent. The latter works by penetrating the surface to protect the wood from deep inside the fibres, leaving the grain of the wood visible.

One option is not necessarily more efficient than the other. Paints require less maintenance and present a wider variety of finishing options (colours, sheen, etc.), while stains need to be reapplied every two to eight years depending on the quality of the product (primarily based on their pigment content).

As stains are water-repellent and air-permeable, they allow the wood to breathe and make your surface easier to sand down if required for the application of any product in future. Additionally, staining gives your garden shed a traditional look as the colours tend to resemble natural wood. Applying a stain also leaves the knots and grain of the wood visible.

Step 1 - Cleaning

Whatever your garden shed material – metal, wood or composite – you will have to start by giving it a thorough clean to create a good foundation. Refer to the tips in this guide for specific instructions on how to clean each type of material.

Step 2 - Choosing your product

Determine which finishing and protective products are right for you. This step also allows you to plan for the tools you will require (sandpaper, nylon brushes, wire brushes etc.) as well as any other equipment or protective gear you may need.

Step 3 - Sanding

You will usually need to sand down the entire surface of the garden shed in order to ensure your products bond well. It is best to use a rotary sander (the orbital kind) but a simple sanding block can also work. Sanding over with a 120-grit then 180-grit sandpaper should suffice but this depends on the thickness of the paint or varnish that you're working with. Next, you just need to wipe or brush away any dust.

Step 4 - Applying protection

For metal or wooden garden sheds, it is safest to start with a protective coating. For wood, this usually means an insect- or fungi-repellent. For metal, you will require an anti-corrosion undercoat. Be sure to choose your wood or metal treatment with care.

Step 5 - Finishing

Using a roller or brush, apply your finishing product to the recommended number of layers. Between two layers, you can sand the surface down with 180-grit sandpaper to improve the bond of the second layer and the overall result.

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Paint brushes
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Guide written by:

Lucas, Antique wood-worker, Gloucester, 28 guides

Lucas, Antique wood-worker, Gloucester

After some time busting my hump at construction, specifically at renovation, painting, carpentry, laying kitchen and bathroom tile, I decided to get my degree as a Carpenter. And I did well because nothing is more pleasant than working on a timber frame or designing a wooden house. Everything about woodworking fascinates me, and building my own home in this material is one of my goals. I’m also a follower of construction tools: I love to learn about innovations, the way they’re used, the tips and tricks, or the performances of each new tool on the market, whether it’s for woodworking or not. I would be happy to advise you and help you with your choices. Happy Tinkering.