You’ve thought about buying a garden room to add to your home. You think it could be a nice place to enjoy a summer evening, or to work from home without getting distracted by the housework. But you don’t want to pay good money for something that’s only going to last a few years. If you’re going to take the leap and buy a garden room, you want to know that it’s built to last. Otherwise it’s just not worth the fuss.
You’re not sure how much you need to spend to get something that’s guaranteed to hold up in the Scottish weather, though. The more expensive, the longer it’ll last, right? Well, it doesn’t always work like that. At Gillies & Mackay, we’ve been crafting timber buildings for nearly 40 years. We’d consider ourselves experts when it comes to buildings that can withstand the Scottish climate. I can’t tell you how many times a customer has used the phrase “It’ll outlast me” when referring to our builds.
The thing is, price doesn’t tell you everything — especially when it comes to longevity. But, there are some essentials to look out for when buying a garden room that’s in it for the long run. In this blog post, I cover how insulation, ventilation, timber type, construction and basework all impact the longevity of a garden room.
Does price impact the quality of a garden room?
You might assume that you get what you pay for with a garden room. But, spending more doesn’t necessarily mean better quality. For example, our Radiata Garden Rooms are built with a high-quality spec but are relatively more affordable than a lot of garden rooms of the same standard. This comes down to the way we build them. Our clever 4-layer wall system is exactly what you need for a smaller space (under 12m²) without being overkill.
Other garden rooms are often twice the price of our Radiatas because they’re made to a Building Control-compliant spec. This way of building is ideal for larger structures or permanent living, but not at all necessary for under 12m². Even though some of our competitors are charging twice as much as us, this isn’t a real indication of better quality. It’s all about getting the right garden room for your needs, and if your main priority is longevity there’s criteria to look out for, regardless of price.
Does insulation affect how long a garden room lasts?
A true garden room should always be fully insulated so that it’s fit for year-round use. Insulation is essential to stabilise the temperature in your garden room. Without insulation, the temperature in your garden room will always be close to the temperature outside. This makes the room uncomfortable and inefficient to heat.
Lack of insulation won’t just impact how comfortable your building is. It negatively affects the lifespan of your garden room. The internal panels of your garden room (the floor, walls and roof) will stay close to the outside temperature. Any warm air inside your garden room condenses into water when it meets these cold surfaces. Over time this moisture seeps into the timber causing warping, rot and decay which reduces the lifespan of your garden room. A properly insulated garden room keeps these surfaces warm. This reduces condensation and protects the timber underneath.
A poor-quality garden room would be a building without adequate insulation. This could mean no insulation at all, or insulation only in the walls and none in the floor or roof. A high-quality garden room will have plenty of insulation in the walls, floor and roof. This keeps the space dry and maximises its longevity.
Does ventilation affect how long a garden room lasts?
Ventilation plays an important role in how long your garden room lasts too. Alongside insulation, ventilation controls moisture and prevents condensation. Without proper ventilation, moist air has nowhere to go and is trapped inside the garden room. This leads to the same condensation problems I spoke about above — moisture builds up on walls, floor, and roof and seeps into the timber. This damages the timber and shortens the lifespan of the garden room.
A poor-quality garden room would lack a proper ventilation system which limits airflow and leads to condensation. A good-quality garden room builds ventilation into the design: an air cavity in the walls, dedicated vents, trickle vents windows and doors, and ventilation in the roof and floor. This keeps air moving and prevents moisture build up.
Does timber type affect how long a garden room lasts?
Timber type plays a big role in how long a garden room lasts. Different woods vary in density, moisture resistance, and treatment which impacts how they perform and hold up in the Scottish weather.
What is better: whitewood or redwood?
Whitewood is typically spruce grown quickly in wetter climates like the UK. This results in loose growth rings, creating a light, flimsy wood that’s prone to movement and moisture ingress. Redwood on the other hand, is usually pine grown slowly in colder climates like Norway and Sweden. This creates tight growth rings and a dense, stable timber.
Further reading: Whitewood vs Redwood
What is untreated timber?
Untreated timber is vulnerable to moisture, insects, rot and decay. Treated timber, whether it’s through heat-treatment, pressure-treatment or surface-treatment, is protected against insects, rot, decay and sometimes even moisture. At G&M, we use ThermoWood to clad our Radiata Garden Rooms. This heat-treated timber is protected from insects, rot, and decay and highly resistant to moisture and shape changes.
What is uncapped composite?
Uncapped composite is a wood-plastic composite that lacks a protective polymer outer layer. Without this layer the wood fibres are exposed to moisture. This causes the composite to warp, buckle or crack within a few years. Capped composite, though, has this protective layer and is protected against stains, scratches and UV. This makes it durable and long-lasting.
What is OSB?
OSB is a strong material, but is only suitable to use in places where it’s guaranteed to stay dry. When OSB is used in a garden room without a watertight construction, moisture will cause OSB to swell, rot, and eventually fail.
A poor-quality garden room would be built from materials like fast-grown whitewood, uncapped composite, untreated timber or exposed OSB. These timbers are more vulnerable to moisture damage, resulting in a shorter lifespan for the garden room. A high-quality garden room will be made from timbers like slow-grown redwood, treated timber like ThermoWood or capped composite. A garden room built from these materials will have protection built-in, ensuring it stands strong and is long-lasting.
Does construction affect how long a garden room lasts?
The construction of a garden room is going to significantly impact its longevity, because this determines how well a building can keep water out.
What is a single-skinned garden room?
Technically a garden room should never be single-skinned because it should be fit for year-round use. However, there are plenty of single-skinned garden rooms on the market. A single-skinned building is any building that has only one layer of material making up its full wall.
Timber is porous so a single layer of timber is always susceptible to moisture ingress, where water seeps through pores in the walls. A little moisture ingress is completely normal in single-skinned timber buildings. However, it’s not ideal for garden rooms and will reduce their lifespan compared to layered constructions.
If moisture ingress is more serious and doesn’t have time to dry out, water can build up in your garden room creating mould, rot, and leading to larger leaks. Eventually, the moisture will break down the timber, and lessen the lifetime of the garden room.
What is a layered garden room?
A garden room with a layered construction and air cavity is protected from moisture ingress, preserving the timber and creating a long-lasting structure. This is how we construct our own Radiata Garden Rooms. Any moisture that gets through the outer cladding, hits the air cavity and can’t go any further so simply dissipates. This leaves the interior of the garden room completely dry. The garden room walls, floor and roof are protected from moisture and stay solid.
A poor-quality garden room will be single-skinned, making it vulnerable to water ingress, and reducing its longevity. A high-quality garden room should have a layered construction with an air cavity which keeps it watertight and maximises its lifespan.
Does basework affect how long a garden room lasts?
A garden room needs a level, solid base to properly support it. If a base isn’t level your garden room will sit out of square. Also, if a base isn’t solid or strong enough, your garden room can sink unevenly, and be out of square. When a garden room is out of square timber boards can shift and warp creating gaps between the boards and around windows and doors. These gaps let in moisture and eventually lead to leaks, mould and rot.
A level, square base that’s solid and strong enough to hold up your garden room will keep it structurally sound for its lifetime, maximising longevity.
A poor-quality garden room won’t have an adequate base. This could be a base that isn’t level, has cracked slabs, or even no real base at all (a garden room thrown straight down on grass – the horrors!). A well-made garden room will have a base that’s the right size and weight to support the building, as well as being properly levelled and solid. For example, all of our Radiata Garden Rooms can go on slabbed bases because of their relatively light weight, and small footprint. Whereas our larger, heavier, Blackstone Garden Rooms need a concrete base to support them.
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How long should a garden room last?
Poor-quality garden room
- No or minimal insulation
- No or inadequate ventilation
- Made from fast-grown whitewood, untreated timber or uncapped composite
- Single-skinned construction
- Sits on an unlevel, inadequate or no base at all
A poor-quality garden room with all of these issues, likely won’t last 5 years before moisture ingress becomes a real issue and the garden room fails.
A mid-tier garden room might have some of these criteria ticked off, but lacking in others, for example:
- Some insulation
- Some ventilation
- Made from whitewood that is pressure-treated
- Layered construction
- Sits on a level, solid base
Depending on what criteria the garden room does and doesn’t have, a mid-tier garden room could last between 5 – 15 years.
High-quality garden room
- Fully insulated
- Well ventilated
- Made from slow-grown redwood, treated timber or capped composite
- Layered construction
- Sits on a level, solid base
A good-quality garden room that meets all the longevity criteria will likely last between 15 – 30+ years.
Our own Radiata Garden Rooms are fully insulated, ventilated, clad with Radiata Pine ThermoWood, feature a 4-layer wall and go on top of a level slabbed base. They’re guaranteed for 30-years and will last much longer with the right care.
Cheap vs Expensive Garden Room: How long will it last?
Whether a garden room is £2,000 or £20,000, it’s the insulation, ventilation, timber type, construction and base that determine how long it’ll last. Not the price tag. In Scotland’s climate, keeping moisture out is what keeps a garden room standing strong for years to come. So a building that gets these five factors right could last anywhere from 15 to 30+ years, while one that skips them might not make it past five.
If you want a garden room built with longevity in mind, check out our Radiata Garden Rooms here. They’re guaranteed for 30 years, and built to outlast that with the right care.
