Featured image for “Garden Room or Home Extension: Which is best for you?”
By Amy Hanlon on 16 Jun 2023

Garden Room or Home Extension: Which is best for you?

Home extension or garden room? Are they really equivalent to each other?

I get it; garden structures can be confusing. They often look pretty similar, and if it’s not your area of expertise, you probably don’t know your gazebos from your summerhouses or your sheds from your garages.

Because of this, people often arrive at our Show Area under the impression that garden rooms are just fancy sheds. 

But here’s the thing. There is no structural reason not to do anything you do in a brick-and-mortar home in a well-built garden room. 

You could put a kitchen in a garden room. You could sleep in there. Bathroom and shower? No problem! You can do anything in a garden room that you can do in a house.

If you don’t believe me, you can ask the government! A garden room with a five-tier wall structure is fully compliant with Building Standards. This legislation exists to make sure that buildings for living and working in are safe, efficient and sustainable, whether they’re timber garden rooms or stone houses

So if you’re thinking about a home extension, it’s definitely worth checking out garden rooms.

Differences between a Garden Room and an Extension? 

A home extension with French doors and a tile roof. The doors open out to a patio and bedding plants.
A home extension from SRJ Windows

The most obvious difference between the two is that one is joined onto your home, and the other is a separate building in the garden. 

It is possible to add a timber extension to your existing house, but generally, a garden room is a separate, free-standing structure. 

A home extension, on the other hand, is a fixed part of your home, joined onto the main structure, which gives you extra rooms or a larger existing room.

Home Extensions vs. Garden Rooms: How much do they cost?

While cost isn’t the most important thing, when we’re talking big numbers it’s a good idea to understand a budget.

How much do Home Extensions cost?

A tricky question, this one. But builders often use a “per square metre” estimation. In Scotland in 2023, these vary from around £1700 to around £3000 per square metre.

Be aware, however, that these costs come from builders, and cover the costs of the actual building itself. Here are some of the things that these estimates don’t cover:

  • Surveyor fees (~£500-£800)
  • Architectural fees (~£1200-£3000)
  • Structural engineer fees (~£500-£800)
  • Planning application fee to the local authority if planning permission is needed. (£350)
  • Building warrant fee to the local authority (~£600-£800)
  • Groundworks. (~£7000-£10000)
  • VAT (20% of the labour, materials and services)

So while you can roughly calculate the cost of building an extension based on its size, this doesn’t actually give you a very clear indication of what the project will cost. The only way to get an accurate quotation is to start planning the project with a building or architectural firm. Because extensions are bespoke projects the cost will very much depend on your individual wants and needs.

How much does a Garden Room cost?

A timber garden room painted pale blue. It has an apex roof, sliding patio doors and a large window.
The total cost of this garden room project was £24,779.

The specifications and materials used for a garden room will affect the cost of your building, but as a general guide, a building control-compliant garden room will cost between £1500 and £1800 per square metre. The cost per square metre is generally less as the building gets bigger. 

Garden rooms are also highly customisable, which means that it’s difficult to give exact figures without knowing exactly what the customer needs.

However, garden rooms also involve far less paperwork and administrative costs than home extensions. In most cases, you won’t need a surveyor, structural engineer or architect. And depending on the size and details of your project you may not need planning permission or a building warrant

While this cost accounts for the building itself, there are fewer additional costs involved with a garden room. Groundwork adds around £2000-£4000. Electrical costs will depend on how many sockets and fixtures you want but are usually around £1000-£1300. Plumbing costs will vary depending on the project. 

Generally speaking, a garden room project will be cheaper than a similarly-sized extension project.

Home Extensions vs. Garden Rooms: How long do they take to build?

Everyone wants their new space yesterday, but that’s probably not going to be realistic for either building. But how long can you actually expect to wait?

How long does it take to build a Home Extension?

Depending on the size and complexity of your project, a home extension can take anywhere from 8 weeks to 24 weeks, or even longer. Builders will try to work with you to avoid you having to relocate while they do their thing, but there may be situations where you can’t stay in your home while your extension is built. As well as potentially adding to the cost of the project, finding alternative accommodation is a big inconvenience.

Another thing to consider is the lead time between finding a suitable contractor and starting the project. Home extensions are best built in the summer months, so there are busier times and quieter times of the year. Even though you’ve agreed on all the details with your builders, a long wait may be on the cards.

How long does it take to build a Garden Room?

Again, there’s that old “depends” again. But a garden room can be installed in anything from a few days to a couple of weeks if the project is managed efficiently. Because a garden room is not attached to your house, you won’t have to relocate, and there’s minimal disruption. 

Different garden room companies will have different lead times. You could wait between 6 weeks and 6 months between finalising all the details and having your garden room installed.

Home Extension vs Garden Rooms: How long do they last?

Either of these projects is a big investment, so it’s important to understand how long each of these is going to last in your home.

How long does a Home Extension last?

A 10-year warranty on a home extension is pretty standard. That’s not to say that an extension will only last 10 years, but after that point, any structural defects or faults are no longer covered. 

Like your home, an extension should be properly maintained and looked after, but you certainly shouldn’t be expecting to have to replace it in anything less than 25 years. A well-built extension should be as structurally sound and long-lasting as your home is.

How long does a Garden Room last?

A well-built garden room should also be as structurally sound as your home is. 30+ years is a perfectly reasonable expectation from a good-quality building. That said, maintenance is critical when it comes to timber buildings. 

Painting the exterior of your garden room will protect the building from the elements and add to its life. Roofing materials will also need maintenance, but steel roofing can be guaranteed for up to 20 years, so this isn’t something you should expect to have to attend to regularly.

Minor repairs may be necessary as the building gets older, but you shouldn’t have to expect to completely replace a garden room in anything less than 25 years.

Extension or Garden Room: Which one is right for you?

If you’re looking to add more space to your home, either of these options will do that for you.

Deciding whether you want a self-contained space in the garden or an additional room attached to your home will depend on your individual wants and needs. Some people love the seclusion and quiet that their garden room gives them. Other people don’t want to have to leave the main house to access that extra space.

The budget should be at the forefront of your mind when planning either of these projects. Make sure you’re aware of all the costs involved, all the time that will be needed for planning and building, and who is responsible for managing the project. 

Once you’ve finalised all these details all you have to do is figure out how you’re going to decorate your new space! What? You didn’t think you were done, did you? There’s a whole other world of paint colours and wallpaper samples waiting for you on the other side!

And you can always come and see a range of garden rooms here at our Show Area. There’s no substitute for seeing these buildings in person.

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