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How long does a timber garage last?

Timber? For a garage? Surely that won’t last long?

Listen, we get it. We’ve all seen grey, sagging structures that you wouldn’t store a bag of tatties in, never mind your prized cars. Timber garages like this really won’t last long. But you do have other options.

Whether you choose a concrete garage, a brick garage or a timber garage, you want a building that will stand solid for many years, and keep its contents safe and dry.

If your heart is set on a timber building, there’s one extremely important thing you have to consider:

How long will a single-skinned wooden garage last?

A single-skinned timber garage will only last around 10 years.

Within this time, repairs and replacements of timbers will likely be needed, but even with the best paint and regular maintenance your big car shed will eventually succumb to the harshness of the weather around these parts.


If you’re wondering what on earth I’m talking about, don’t worry. If you’re after a timber garage that will last longer than One Foot In The Grave did, this article explains exactly what you need.

What is a single-skinned garage?

A cheap, single-skinned garage made of timber, with a felt roof and wooden double doors.

A single-skinned timber building has one layer of timber forming its walls. This “skin” stands between the weather and the inside of the building. It’s usually made of interlocked or overlapping timber boards, fixed together to form panels.

This is how you construct a shed. They have a frame, wall panels, a roof, and if you’re lucky, a floor.

Shed walls are generally made from timber boards that are between 5mm and 20mm. A shed with 5mm walls will be flimsy and light, and unlikely to keep out the weather.

Good quality sheds are built of thicker cladding so they are solid and more weatherproof.

Single-skinned garages are effectively big sheds. The problem with these big sheds is that they don’t keep water out effectively. Once a timber building is over a certain size, a single timber skin isn’t enough.

What problems do single-skinned timber garages have?

The number one thing that a building needs to do is keep out water. Whether your garage is built of metal, brick, concrete or timber, water ingress will cause problems. Water inside a building encourages mould, and rot and damages the structure, as well as anything inside.

Because wood is porous, it easily takes in water from the outside of the building. If the conditions are right, that water will move into the building through the walls. What sort of conditions am I talking about? Rain, snow, more rain, hail, sleet, yet more rain… All the delights of the average Scottish summer!

How thick should wooden garage walls be?

A large timber garage stained golden brown, with a dark grey roller garage door.

Surely the solution to this problem is to make the walls thicker? This seems like a reasonable suggestion, but it’s not quite so simple.

Think of a Canadian log cabin. Thick timber walls, cosy and snug inside. As timber is a natural insulator, it’s perfect for keeping out the snow in the harsh winters and staying cool in the warm summers.

Then think of the Scottish climate. The issue we face that Canadian cabins don’t is that our weather is famously changeable. If the seasons slowly change from warm to cold over the course of several months, timber can adjust slowly to those changes.

But when the seasons all show up over the course of a single day – hiya, Scottish weather! – timber struggles to keep up with exposure to heat, cold, moisture and dry conditions. This causes movement, swelling, cupping and warping. The thicker the cladding, the more influential any movement of the timbers will be.

What is the best cladding thickness for a timber garage?

So there’s a sweet spot for timber buildings, between around 16mm and 20mm. Anything under this won’t keep the weather out. Anything over this won’t confer any significant benefits and will risk shifting.

However, the size of the building also impacts how watertight it will be. Once it’s bigger than around 16′ x 10′, even with thicker cladding, you can’t guarantee that a wooden garage will be watertight. So what’s a timber garage-lover to do?

What’s the best construction for a wooden garage?


If it’s good enough for lasagne, it’s good enough for timber garages!

After we identified that even our best building methods weren’t guaranteeing dry garages, we realised we had to try something different. So we developed a layered construction for our wooden garages that is guaranteed to keep the water out. It looks something like this:

A diagram of the Gillies & Mackay timber garage specification, showing the layers of timber, air, dampproof membrane and insulation.

Look at all those lovely layers! As well as the outer cladding, there’s an air cavity gap, a damp-proof membrane, and a layer of OSB for its insulating properties. Unlike a log cabin or a big shed, wooden garages have several barriers to water rather than one thick barrier.

We use pressure-treated framing that’s resistant to rot and insect damage and is the foundation of a seriously strong structure.

Speaking of foundations, we install our wooden garages on a 1500mm concrete plinth, built on a layer of Type 1 hardcore. This combination of building specification and base specification is a surefire way to keep your garage dry all year round, no matter how much rain and snow we get.

How long does a 3-tier garage last?

This layered construction doesn’t just mean that your wooden garage will stay watertight. It also means that it will stand solid for a whole lot longer than 10 years. Try 30 years.

If you look after your Gillies & Mackay garage you’ll have a beautiful, solid, watertight structure that will last for decades.

What are the benefits of a wooden garage?

A wooden garage is a classic, beautiful building. If it’s built properly it’ll last just as long as metal or concrete garages.

Because timber is naturally breathable a wooden garage is much less likely to suffer from condensation, which is often a problem in brick, concrete and metal garages.

Also, the thermal performance of wood means that layered timber garage walls can be much thinner than brick or concrete equivalents. This means more floor space inside the building, which means more space for your car, storage, workshop, or whatever it is you want your garage for.

As timber is a natural insulator, the walls of a wooden garage feel warmer to the touch than the walls of metal or concrete garages do. The air gap and OSB ensure that warm air inside the garage meets a warm wall, which is a great way to prevent condensation.

How do I help my wooden garage last even longer?

As with all timber buildings, there will be some maintenance. Timber garages need some love, starting with a coat of paint.

A good water-based exterior paint protects your gorgeous garage from the elements, and if you repaint it every few years it will stay just as sharp-looking as it did when it was installed.

Other maintenance includes cleaning your garage and as the decades pass, you should look out for signs of wear and tear.

Where can I buy a wooden garage?

A timber garage painted dark brown, with an adjoining carport. A motorbike is parked inside the garage, and a VW camper van is parked under the carport.

All our timber buildings are on display right here at our Show Area in Errol, where we design and manufacture sheds, summerhouses, garden rooms and garages. Whether you’re looking for storage space, somewhere to enjoy your garden or more living space, we can help.

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