Looking After Your Timber Garden Building

A timber garden building can last for many years if you look after it. Most problems, such as rot, leaks, sticking doors and mould, start small and are easy to prevent with a little care each year. This guide explains how timber is treated, how often to re-treat it, and what to check through the seasons.

How your building's timber is treated

New garden buildings are usually protected in one of two ways, and it affects how much care they need.

Dip-treated timber

The timber is dipped in a preservative at the factory, which gives it colour and protection at the surface. Dip treatment is a good start, but it doesn't last on its own. Dip-treated buildings normally need a coat of treatment when they're built and then every year. For example, the Power Sheds 10-year guarantee against rot, decay and insect infestation is subject to annual re-treatment.

Pressure-treated (tanalised) timber

The preservative is forced deep into the timber under pressure. This gives long-lasting protection against rot and insects, which is why pressure-treated buildings, such as Suresheds, often carry longer guarantees. Pressure treatment doesn't stop the sun and rain weathering the surface, so a coloured stain or finish every few years keeps the timber looking good and adds a water-repellent layer.

Whichever you have, check your building's guarantee terms on our Warranty & Guarantees page, and keep a note of when you treat it.

Treating a new building

• Treat soon after assembly. Don't leave bare timber exposed to a wet season. Several of our log cabins come with a 5-litre tin of exterior wood preserver for exactly this reason, to apply on assembly and then yearly.
• Treat the hidden bits. The underside of the floor, the bottom edges of the cladding and the ends of boards take in moisture most easily. If you can, treat these before the building goes together.
• Treat inside too for log cabins, as the logs move with moisture on both faces.
• Pick dry, mild weather. Most treatments need a dry surface and a few dry hours afterwards. Check the tin for the right temperature range and drying time.

How often to re-treat

These are general guides. Your manufacturer's instructions come first, especially where a guarantee depends on it. A good sign it's time to re-treat is when rain soaks straight into the timber instead of beading on the surface.

Choosing a treatment

We stock the Protek range of British-made wood treatments, including Protek Shed & Fence in natural and garden colours, Wood Stain & Protect and Wood Preserver ++, a preservative that also works as a primer. Some preservatives contain insecticides that are harmful to cats, bees and aquatic life, so always read the label, keep pets away while you work, and don't apply near beehives or ponds. Power Sheds and Sovereign buildings also have their own matching paint and wood stain and shed treatment.

Looking after the roof

The roof takes the worst of the weather, so check it every autumn and after storms.

• Felt roofs: look for tears, lifted edges, blisters or loose nails. Small tears can be patched; worn felt should be replaced before water reaches the roof boards. Heavier felt or felt tiles last longer than standard felt. We sell heavy-duty felt, standard felt rolls and felt tiles.
• EPDM rubber roofs: these are low maintenance, but check the edges and trims, and keep the surface clear of moss and debris.
• Gutters: clear leaves and moss so water runs away from the building, not down the walls.
• Overhanging trees: cut back branches that rub the roof or drop leaves and sap onto it.

Ventilation and condensation

Condensation is one of the most common causes of damp in garden buildings. Warm, moist air meets cold glass or timber and turns to water. It's worst in autumn and winter, and in buildings used as offices or gyms.

• Open windows or vents on dry days to let air move through.
• Don't store wet items, such as garden furniture cushions or damp tools, without letting them dry first.
• Leave a small gap between stored items and the walls so air can circulate.
• Avoid gas or paraffin heaters in a closed building, as they produce a lot of moisture. A well-ventilated building with electric heating is better.
• Keep the base clear so air can move underneath the floor.

Around the base

Rot usually starts at the bottom. Keep soil, plants, leaves and grass clippings away from the walls, and don't let water pool around the building. A strip of gravel around the edge helps stop rain splashing back onto the cladding. If the building has moved out of level, doors and windows will start to stick. Our base guide explains how to get this right.

Your winter checklist

• Check the roof and gutters before the first big storms.
• Oil hinges, locks and bolts so they don't seize.
• Brush heavy snow off the roof so its weight doesn't build up.
• Check that doors and windows still close properly. Timber swells in wet weather, so a little stiffness is normal, but a door that suddenly won't close can mean the base has moved.
• Ventilate on dry, bright days.
• Greenhouses: clean the glazing to let in as much winter light as possible, check glazing clips, and ventilate on sunny days even in winter.
• Store garden furniture cushions and fabric covers somewhere dry inside the house if you can.

Common questions

How often should I treat my shed?

Dip-treated sheds usually need treating every year. Pressure-treated (tanalised) sheds need it less often, though a stain or finish every few years helps protect the surface. Always follow the manufacturer's instructions, as some guarantees depend on regular re-treatment.

When is the best time to treat a shed?

Choose a dry spell with mild temperatures, usually late spring to early autumn. The timber should be dry, and you need a few dry hours afterwards. Check the tin for the right conditions.

How do I stop condensation in my shed or garden room?

Keep air moving by opening windows or vents on dry days, avoid storing wet items, leave gaps between stored items and the walls, and use electric rather than gas or paraffin heating.

How long does shed roofing felt last?

It depends on the grade of felt and how exposed the roof is. Check it every autumn and after storms, patch small tears and replace worn felt before water gets through. Heavy-duty felt and felt tiles generally last longer than standard felt.