The complete guide to garden rooms

You want somewhere outdoors with shelter and the ability to hold heat. A garden room is the answer. It’s insulated, quiet, and has power for your appliances.

Any shape or size is possible with your garden room, and it doesn’t require any disruptive building work, provided you pick anything but blockwork.

No planning permission is necessary either, with only a few rules to abide by to satisfy permitted development. You can then literally get it built and notify no one.

This article is a complete guide to garden rooms, spanning what they are, the different types, how they compare to extensions, and more.

What is a garden room?

It’s an outbuilding with glazed doors and windows, thermal insulation, an electric hookup, and sometimes a canopy for a hot tub or furniture.

Your garden room could be an office, gym, gaming zone, art room, or anything else you could do inside your home, but don’t have the space for or would rather do with a view outdoors.

Garden rooms are often onsite builds from timber or blockwork. However, timber isn’t impervious to the weather, and blockwork greatly restricts the design potential of the structure.

The modern construction method is prefabrication, as with the Leka composite garden room. It contains no wood, no metal, and is factory-assembled, so the build time is therefore reduced by a factor of around ten, taking mere days from delivery to sign-off.

Why garden rooms are so popular

No one wants to be indoors all the time. But no one wants to spend time outdoors when the weather is foul. And even when the weather’s splendid, you don’t always want to be so exposed. Garden rooms solve all these use cases.

Garden rooms are effectively outdoor spaces, but with an internal space that you can use all year round. They are insulated, which does two things:

It keeps your space cool in the summer. Any sunlight that hits the roof and walls of your garden room won’t heat the space as it would with a shed or log cabin.
It traps warmth in the winter or on any cold occasion. The heat you add to your garden room stays in it for longer, giving you a temperate place to spend time.

It’s that temperateness that makes garden rooms so popular as a usable space. You’ll find excuses to be in it. The overall feeling inside a garden room is nothing like what you get with a shed or temporary structure; it’s solid and feels like an extension of your home.

Other reasons garden rooms are so popular:

They don’t need planning permission. We’ll go into this in more detail later. The primer here is that outbuildings in general are classed as permitted development, save for a few rules about boundaries and height.
They make gardens look more complete. Any unused corner, stretch of fence, or muddy, disjointed piece of land is ripe for a proper garden room to fill it out. Your garden will look better and make proper use of its space.
They are desirable and add value to your home. Whatever you pay for your garden room can work its way into your house price, or a portion of it anyway. Any future sale can use your garden room as a selling point.
They have minimal building work and disruption. Subjective to the build type, of course, but the Leka composite garden room has no building work. The prefabricated structure is erected with no disruption to you or your neighbours.

Different types of garden rooms

We can split the different types of garden rooms by construction type, size, shape, and with or without a canopy, which also feeds into size.

As good a place as any to start is with the construction type. We won’t bash any build type here, but just provide information about what goes into construction:

Composite garden rooms

The Leka system has no wood or metal. The construction is GRP, which stands for glass-reinforced plastic, a composite material. It is stronger than standard PC or ABS and highly suited to outdoor applications.

The benefit of composite is that it doesn’t attract condensation, and it is also impervious and UV-resistant by design. The structure is also incredibly strong, using a framework for rigidity that doesn’t creak or start making expansion noises when the sun hits it.

You will typically pay more for a composite garden room than a wooden one, although the gap is usually less than 15%, which you claw back from less maintenance.

An installer sizes your garden room and then orders fabrication at the factory. The frame, panels, glazing, and internal finishes are delivered onsite and assembled.

Wooden garden rooms

Timber is a sustainable material and has its own charm. Composite can mimic the appearance of wood, but not its warmth and feel. You can also paint timber again and again, changing its appearance to suit whatever look you want in any given year.

Wooden garden rooms are often cheaper than composite garden rooms, but with a caveat, and that is that the cheaper ones are usually log cabins.

Log cabins are durable and look nice enough, but they have poor insulation without Kingspan or another rigid insulation product in the roof, walls, and floor.

The build time for wooden garden rooms is around five times that of a composite one. The timber is often cut on site and sanded down where appropriate, which makes a mess. There’s a higher chance of disruption in return for a natural-looking space.

Block garden rooms

Block or brick, take your pick. These are classed as permanent structures because they require a foundation and should last upwards of 40 years, roof quality dependent.

The bricks and blocks eat into considerable space and make the building bulkier than wood or composite constructions. The benefit is a solid product that can match the outward appearance of your home, be that sandstone or brick.

Out of all three construction types, blockwork takes the longest. A minimum of four weeks is the norm for the exterior and internal structure.

Because a builder constructs a blockwork garden room on site, the quality of your builder comes into play with more room for error and much more mess.

It’s often the case that blockwork garden rooms come in at around the same price as high-end wooden ones, but without their charm. Additionally, they have no structural benefit compared to composite and are sometimes worse insulators.

Different sizes and shapes

Garden rooms are rectangular or square, expressed in feet or metres. The common sizes for square ones are 2 x 2m, 2.4 x 2.4m, and 3 x 3m. Rectangular garden rooms are usually 2.4m or 3m deep and 4m, 5m, or 6m wide.

Because the Leka composite garden room is prefabricated, it can be built to accommodate any size requirement, so odd spaces are no problem. We have seen garden rooms that are 7 x 3.6m, for example, to fit the customer’s garden perfectly.

There are also garden rooms with dimensions of say 7 x 3m, but only 4m of the construction is the internal space, with the rest a canopy.

Canopies are entirely optional for garden rooms and do reduce the amount of indoor space you have in your garden room, but they provide fantastic seating and space for a spa. Even a barbecue or a pizza oven is on the cards.

Garden rooms vs extensions

So an extension requires knocking a wall out of your home or widening an opening to create a new opening and then building a new wall around it.

That project sees you increase the indoor space of your home not via an outbuilding but with changes to your house’s footprint.

Garden rooms are considerably more cost-effective than extensions, but they are entirely separate from your home. If the idea behind your new space is to create a new living area in your home or extend the kitchen, an extension is what you want.

A garden room satisfies the itch for an outdoor space that is separate rather than connected to your home.

The practical benefit of a garden room is that it doesn’t require significant building work and won’t disrupt your life during the build time.

Timber vs composite garden rooms

Timber is popular, no doubt about it, and it isn’t going to get knocked off its perch anytime soon due to its natural appeal. But composite does a pretty good job at mimicking its appearance with substantially better longevity. Details below.

The benefits of timber garden rooms

Natural product. It ages gracefully, provided you treat it and don’t let it rot.
Renewable. Trees grow, and the timber used in construction is usually certified to be from sustainable sources.
Repairable. High-quality timber lasts, but in the event it doesn’t, replacing a warped beam or cracked length of cladding is easy.
Customisable. Paint it and stain it to your liking. The wood will take to it and provide a decent finish, provided your coating is of good quality.

The downsides of timber garden rooms

It rots. There’s no way around it. Water will lead to rot over time.
Upkeep. That paint and stain isn’t optional, but necessary. Most timber requires a fresh coat of sealant or waterproofing every one or two years.
Changing appearance. For all timber’s graceful ageing, not everyone loves it. Your garden room will be different six months on from being new.

The benefits of composite garden rooms

It’s longer-lasting. Composite doesn’t rot or warp.
It can match the look of wood. You won’t notice the difference from a foot away due to how realistic the latest composite is.
Better insulation. Composite rooms are prefabricated with no gaps or defects in their construction. Any insulation can do its job better.
Faster build times. Rather than one to two weeks for a standard timber build, you’re looking at a few days for composite garden rooms.
Minimal disruption during the build. A benefit mostly for those who work from home, have neighbours, or live with lots of wildlife.

The downsides of composite garden rooms

The cladding is a ‘what you see is what you get’ product. You can’t paint or stain it.
They’re more expensive than cheaper wooden cabins. If you want the cheapest possible garden building, composite isn’t for you.

Choosing the best cladding

Composite garden rooms have several layers. The outside is an external cladding, made from UV and weather-resistant GRP boarding. Internally, there’s a lightweight cladding board, which provides either the finish or the surface for plasterboard.

Choosing the right cladding is not a matter for you as the customer, but for the fabricator, who should specify the correct cladding for their builds. You can then hopefully choose the finish, as is the case with Leka composite garden rooms.

Leka composite garden rooms have two weather-resistant external cladding systems, and the internal cladding supports our high-grade insulation.

The external finishes include:

Frontonio range

These are natural finishes with natural grooves (no fill). The products with a V next to their name have a black or dark infill:

Oak
Golden Oak
Honey Oak
Winchester
Walnut
Oak V Black
Golden Oak V Black
Walnut V Black
Light Oak V Black

Solvonio Range

A modern cladding range with or without infill for the grooves:

Natural Oak
Cedar
Grey Oak
Chocolate Oak
Natural Oak V Black
Cedar V Black
Grey Oak V Black
Chocolate Oak V Black

Are garden rooms warm in winter?

Add some heat to your garden room via an electric radiator or air blower, and it will trap it extremely well with a U-value exceeding the latest eco-homes.

Our experience is that Leka composite garden rooms heated to 21°C with an outdoor temperature of sub-8°C lose approximately 1°C of heat per hour, provided the windows and doors are closed.

There’s also some direct heat transfer from the sun, depending on whether the glazing is oriented facing it. Any sunlight that streams through the glazing will heat your space, making it warmer in the winter without a heater. Shade and blinds can prevent the same in summer.

Planning permission explained

Garden rooms are outbuildings. They fall under the same planning permission rules as sheds and playhouses, all of which are specified as permitted development under planning permission laws as set out in the Planning Portal.

Some rules can send a garden room over the permitted development rights and require permission before building. These are as follows and apply to houses, not flats or maisonettes, which have different rules:

You can’t build your garden room on land forward of the wall of the principal elevation.
The roof shouldn’t be higher than 2.5 metres if within 2 metres of the property boundary.
The garden building should be single-storey.
Any veranda or balcony should not exceed 0.3 metres.
Garden rooms on designated land at the side of properties require planning permission.

To summarise: you don’t need planning permission to erect a garden room provided you keep it under a certain height and distance away from boundaries. Also, it shouldn’t be self-contained accommodation for sleeping and living.

How long do garden rooms last?

The Leka composite garden room has a 40-year warranty. That’s the bare minimum to expect from one of our prefabricated garden rooms.

Other products have different warranties that we can’t speculate on. The industry consensus is that composite garden rooms have a lifespan of multiple decades and should outlast the time you spend living in your house.

The same probably cannot be said for timber and blockwork garden rooms. Wood rots and blockwork can subside as the ground beneath it gives way. Composite garden rooms are the most reliable and long-lasting of the lot.

The reason for the longevity of composite garden rooms is two-fold: the quality of the materials and the tolerances at the factory.

Leka’s composite garden room is fabricated with precision so that every panel, frame, cladding section, and finish fits together perfectly with no give.

Common problems with cheap garden rooms

Low-quality insulation. Instead of PIR or XPS insulation, cheaper garden rooms use mineral wool or fibreglass batts, which are less expensive and don’t have anywhere near the insulative qualities.
Low-grade windows and doors. It isn’t uncommon to see Chinese imports without proper U-values or B-grade windows and doors. A grade is the minimum to look for. You’ll leak heat without them.
Condensation and dampness. From metal that attracts condensation, and a lack of ventilation. The glazing should have vents, or you should have an electric vent installed in the building to extract the air.
Thinner construction. All well and good provided it maintains the U-values necessary for adequate thermal performance, but the trouble is that thinner often means cheaper and less capable.
Maintenance requirements. A guarantee that your garden room is a cheap wooden build. Some cheap composites also discolour in the sun, requiring replacement. It’s best to go for the highest-quality building you can the first time around.

FAQs

Can you sleep in a garden room?

Yes. We’ll even add the opinion that it’s your garden room, so you can sleep in it temporarily as much as you like. There’s a rule within planning law that says it can’t function as permanent accommodation or become a separate self-contained dwelling, though, meaning you can’t live in it full-time.

Can my garden room have a toilet?

Yes, and it doesn’t shift your usage over to permanent use, either. A toilet and a sink are worthwhile additions to save you from running into your house, but they will require a partition in your garden room, which will eat into the amount of living space you have.

Are there any size restrictions for garden rooms?

The planning laws say your garden room should take up less than 50% of your garden or the land around your house, and be less than 2.5m tall if within 2 metres of a boundary. However, you can apply to remove these restrictions with planning permission.

What base is necessary for a garden room?

The Leka composite garden room doesn’t require a concrete base. It can go on grass, gravel, or on any solid base. Ground screws are necessary for soft and malleable surfaces. They are installed in less than one day and provide a solid foundation.

How long does it take to build a garden room?

A composite garden room that is prefabbed takes on average three to four days to erect and an additional one to two days for the internal finishing. Timber garden rooms take at least twice as long, and block builds can take four to five weeks.

How much will my garden room cost?

It is impossible to say how much your garden room will cost without knowing its size and specification. As a general rule, you are looking at £15K to £35K, but it all depends on the level of finish and extras, such as running water.

Log cabin or garden room? Which is best?

Garden rooms. A few reasons for that. They are insulated and can use composite in their construction, which is impervious to the weather and never needs maintenance. A log cabin will cost you less, but it’ll get hot in the summer and cold in winter due to poor insulation.

What size garden room should I get?

The overall size is going to depend entirely on your garden and what looks appropriate. We always say to size up by 0.5 to one metre if you can. You can always make use of additional space, and you might wish for more in the future.

The Complete Guide to Garden Rooms | By Leka Xi