Single storey extension planning
A single storey extension will transform your home. Not only will it give you the extra space you need but it also has the potential to add value to your property.
Read on to find out typical single storey extension costs, the rules around planning permission, and the key considerations when planning this exciting project.
Key considerations for building a single storey extension
Even building a small extension has various moving parts, and it pays to take a planned approach.
With that in mind, here are our top tips when starting to plan your single storey extension.
1. Create a brief
Whether you intend to project manage the extension yourself or call in the help of the experts, a clear brief is a solid starting point to make sure that the end result matches your vision for the space.
Be clear on why you want an extension, for example, to have a more sociable kitchen/dining space. Then use this as a reference point to guide you through the various decisions you’ll need to make along the way.
It’s also useful to gather examples of concepts and ideas for single storey extensions you like to help shape your designs.
Related content: Extension ideas for all property types
2. Understanding planning permission for an extension
Small extensions (such as single storey projects) sometimes fall within Permitted Development (PD) if specific criteria are met. This means that planning permission isn’t required.
However, it is still advisable to apply for a Lawful Development Certificate from your local authority upon completion. This will ensure you have the relevant paperwork should you come to sell your property in the future.
If you live in a listed building or conservation area, specific planning rules will apply. It’s always best to check with your Local Planning Authority first.
An experienced local builder will have a good understanding of local regulations, which can prove invaluable when planning what sort of extension is best for your property.
Related content: Planning permission for an extension
3. Consider your budget
Various factors impact the cost of a single storey extension, including its size, the scope of the work, and the materials you choose. This is such an important part of the project that we cover a whole section on this a little later.
However, as a ballpark figure, build costs typically sit in the region £1,800 - £3,000 per m² for an extension.
Budgeting a contingency of 20% is recommended to cover unforeseen costs, as is making design decisions (flooring, finishes etc) up front to help keep your budget in check.
Related content: Plan your budget with our house extension cost guide
4. Hire professionals for your extension
Some homeowners opt to project manage their extension themself, while others call in the experts to either facilitate part of, or the entirety of, the process. But who should you call on?
Architect or Design and Build Companies: To turn your ideas into a reality, enlist the help of a qualified architect or the services of a design and build company. They will draw up plans that match your needs with your budget and guide you through the planning permission process. They can also help to appoint and coordinate other specialists up to the start of the build and will ensure the project stays on track.
Planning consultant: A good idea if you live in a conservation area and have specific planning permissions to adhere to.
Structural engineer: To produce drawings and calculations that meet building regulations.
Quantity surveyor: To help plan and budget for the build materials.
House extension builders: Experienced contractors to lead the construction of your extension in line with detailed plans and building regs.
As you might imagine, good, experienced professionals are booked up in advance. Start your search now to avoid disappointment. Simply enter your postcode below to find all these experts and more in our leading directory.
The average cost of a single storey extension
A home extension is not cheap, therefore it’s important to look at the numbers before you commit to this project. This will also help you to shape the scope of the work and the finishes you choose.
First of all, will your plans add value?
The cost of an extension is one thing. Whether you’ll recoup those costs (when you come to sell your home) is another.
On average, a single storey extension could add between 5-8% to the value of your home. This depends on several factors including the size, style, and finish of your extension, and your location.
With so many inspiring ideas, it’s easy to get carried away. However, it’s best to speak with a local estate agent first who will let you know how much your extension could add to the value of your home. This will help you to plan your budget effectively.
Single storey extension costs
Single storey extensions are usually done at the rear or side of a building.
Several factors will affect the cost of your extension, but as a guide, budget for between £1,800 - £3,000 per m².
Based on this, as a ballpark:
- A 20m² extension could cost £40,000 – £56,000
- A 30m² extension ranges from £60,000 – £84,000
- A 50m² extension could set you back between £100,000 – £140,000
We always recommend getting a selection of quotes – which can be easily done with our request a quote form.
Once you’ve selected your contractor, make sure you agree to a payment schedule in writing. It’s fairly typical to stagger payments throughout the project as each phase is completed.
The process of building an extension
If you’ve not built an extension before, you’d be forgiven for finding the whole process a bit bewildering.
Our guide to building an extension covers the entire project from start to finish, helping you to understand what to expect at each stage.
For an overview of the process from external construction to internal renovation, and the finishing touches, take a look at our guide to building an extension.
What type of single storey extension is right for you?
While a rear single storey extension might be the first image that springs to mind, there are other ways to get that all-important extra space.
Side extensions are a great way to better utilise the often ‘dead space’ along the side of a property. Price up the cost of this project with our handy side extension cost guide.
If you’re looking to max out on the available space, why not consider a wraparound single storey extension? Perfect if you’re looking to extend a bungalow that sits on a good-sized plot.
Consider these options against your original brief to help decide which one might be best for your home and your needs.
If an extension is proving a bit pricey but you desperately need extra living space, follow the trend for a garden room. It’s the perfect place for a home office, teenage hang out, occasional extra bedroom, or even a fitness room.
Single storey extension ideas
Ready to start collating inspiration and ideas for a small house extension? We have a beautiful gallery of single storey extension ideas, including:
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