Use a single storey extension to bring outside space in, maximising your home’s full potential.
Ground Floor Extensions
If you’re thinking of enlarging your home you’ll probably want to aim for maximum benefit from the simplest solution.
Usually this will be with a ground floor extension, also called a single storey extension. However, within this general description there are several options. In this article we’ll explore the choice of solutions, to help you decide how best to add immediate benefits and long term value to your property.
Ultimately, your home extension choices will be determined by five considerations:
- how large you want your extension to be
- how much outside space is available, ie how big is your garden?
- the purpose of the extension (a larger kitchen and living area, or distinct rooms such as a home office)
- your choice of materials, design preferences and your budget
- local Planning regulations.
The great majority of single storey extensions are used to enlarge a kitchen, often as a kitchen/dining room , and with extra family space as well. However, there are many more options, from a home office or a garden room, to more utility space, or a new bedroom suite for a family member no longer able to use the stairs.
The different types of Ground Floor Extensions
Single storey extensions come in different shapes and sizes. The one you choose will depend in part on the space you want to use, and the purpose of the extension. Other factors may be the shape of your home, and whether your property is terraced, semi-detached or detached.
A Rear Extension
As the name suggests, a rear extension runs out from the rear of the house. Often there will be additional outdoor paving or decking to provide a seamless link between house and garden.
Rear extensions often tend to include a re-modelled kitchen-dining room and family living space.
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A Side Return Extension
A ‘side return’ is the original rear extension or ‘outrigger’ of a house that creates a distinctive L-shaped footprint. It’s common to many homes built in the late nineteenth and early twentieth century.
These are easy to find in the London area, typically with terraced or semi-detached properties. A side return extension (sometimes called an infill extension) fills in the space next to the outrigger. Often this is an area which is otherwise difficult to use well; bringing it into the house is a significant improvement.
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A Side Extension
This is an extension along the side of the property. Sometimes it will fill in all or part of an alley or driveway or extend the house sideways into the garden.
An important consideration is outside access to the garden and rear of the property. However, in practical terms this is rarely a problem – it’s just worth factoring in during the design stage of your project.
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An L-shaped or Wrap-around Extension
As the name suggests, this type of extension wraps around two sides of your home. It provides considerable potential to significantly increase the square footage indoors.
The additional space will enhance the look and feel of the house both inside and out.
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The benefits of a Ground Floor Extension
Whichever type of single storey extension you choose, they all come with real benefits.
A ground floor extension will not only increase the available floor area inside your home. It will also
- be a simple or as sophisticated as you choose – there’s real flexibility in terms of size and budget
- add valuable floor space and increase natural light, often beyond the extension itself
- be tailored to all settings – design specifications are extremely flexible
- new extra space embraces open plan living, even in older properties
- provide easier access to your garden
- mean you stay in an area you like.
- mean that additional space takes pressure off the rest of the house and adds value to the property – the actual cash value will differ depending on location and market conditions, but there is a real increase based on additional square footage and the extra versatility gained.
Good Design is Essential
At the heart of a successful single storey extension is excellent design. This should combine the benefits of modern materials and sensitivity to the property. You’ll need architectural designers who combine technical expertise with an inspired sense of shape & form; you’ll need professionals with an holistic approach to the project – experts who are able to master every detail while keeping a secure eye on the aims of the project overall.
As the project falls into place, you’ll need to make decisions about materials and finishes to use, about windows and doors (conventional, sliding or bi-fold, for example), and about the type of roof best suited to your home. You’ll need to consider hidden aspects such as plumbing, heating and insulation. All of these decisions will be easier when you work with specialists who know London properties inside out.
You’ll also benefit from working with architectural designers who are Planning Specialists. That way they can also help you navigate through the Planning Application process, or help you ensure the intended work does qualify for Permitted Development Rights.
Preparation is the key to success
Before work starts, it’s best to have a feasibility study to test your ideas. Here it’s best to employ professionals; doing so will save you time and money. You’ll need advice of architectural designers, structural surveyors and maybe also party wall surveyors. At this point you can consider options for design, materials, size and specifications for internal decorations.
A good feasibility study will include
- ideas for overall design and style, with recommendations for materials to suit your purpose and budget
- suggestions for the best choice of roof style and windows
- the layout of the extension, with implications for plumbing, heating, wiring and insulation
- whether the proposed wok will qualify for Permitted Development Rights
- whether Planning Permission will be required
- the need for structural work (and therefore the need to employ a Structural Surveyor) and/or the need for a party wall agreement
- advice on Building Regulations and how they impact on the work to be done
- the first plans and drawings, ideally with 3D visualisations
- an estimates of costs.
Also factor in that if your home is a listed building, or if you live in a Conservation Area, there will be further requirements on top of those within Planning Permission or Permitted Development.
Once the main parameters are agreed, your architectural designers can commence detailed planning and preparation for your ground floor extension. They’ll help with detailed specifications and start the paperwork to go with your Application for Planning Permission or your request for a Lawful Development Certificate. This will be useful proof, when you come to sell, that no Planning Permission was needed.
What is the cost of a single storey extension?
As with all construction projects, Ground Floor Extension costs vary according to:
- size overall
- complexity of internal layout
- type and size of roof
- choices as to windows, doors and internal finishes
- materials used
- accompanying landscaping of the garden.
The simplest ground floor extension cost need not be high, especially if there are few structural changes to the original property. A straightforward Side Return Extension, for example, could cost in the region of £15,000-£20,000. A more ambitious project, such as a wrap-around extension could cost several times that much.
With extensive structural changes and the highest quality materials and finishes, such a project could cost in the region of £80,000 to £100,000 or more. In between these, at about £35,000 to £45,000, would be a fair-sized rear or side extension with a kitchen, probably being the most frequent example of a single storey extension.
Overall you can work on square metre costs ranging from £1800/m2 for the very simplest extensions to over £2500/m2 for the more expensive materials, features and finishes.
As well as the construction cost for your ground floor extension, you should also factor in professional fees to include architectural designers, structural engineers and a party wall surveyor if necessary, plus building regulations/building control. Also remember the costs of a Lawful Development Certificate or the Planning Application if required, Altogether these will account for 8-12% of the total cost.
Will I need Planning Permission?
Changing the size and shape of your home is likely to require Planning Permission unless the work comes within the definition of Permitted Development. This is a scheme designed to encourage reasonable property development without the bureaucracy sometimes associated with Planning Applications.
Do you have Permitted Development Rights?
If your intended works come within the definition of Permitted Development Rights Planning Permission probably won’t be needed. However, you should definitely get professional advice on this point. If you assume your project qualifies but you are mistaken, putting things right can be expensive and time consuming.
Permitted Development rights are different for different types of property
Permitted Development Rights depend on the context and size of the single storey extension planned. The original size of your house may also be relevant. That said, generally, the type of house also determines the outcome.
- Terraced and semi-detached houses – you can build a rear ground floor house extension up to 3m from the back of the main body of the house. With prior approval from the local Planning Authority and subject to consultation with neighbours you may be able to increase this to up to 6m.
- Detached properties – here you can add a single storey extension reaching up to 4m from the back of the main part of the house. With prior approval from the local Planning Authority and subject to consultation with neighbours you may be able to increase this to an extension which reaches up to 8m from the back of your home.
Other considerations will be to have the materials used be in keeping with the original house. The intended extension should take up less than 50% of the land around the original house and usually must be no closer than 3m to neighbouring properties.
There is further information about Permitted Development Rights on the Planning Portal and gov.uk. These are important resources, but they are also best read in conjunction with your Planning specialist’s advice. The information they provide is either very technical or quite general and can be difficult to interpret without experience.
If you need Planning Permission
If you don’t qualify for Permitted Development Rights you will need to apply for Planning Permission.
You can do this yourself, but it is easier, quicker and more cost effective to employ a Planning specialist. Good firms of architectural designers also have Planning experts who can prepare the paperwork and guide you through each stage of the process.
While there are advantages in using Permitted Development Rights it is also the case that they can restrict what you do. Securing Planning Permission, though more onerous, does come with the advantage that you can apply for permission for more ambitious projects. This might be useful in terms of your designs and choice of materials, and especially where you want to add a larger than usual ground floor extension.
Choosing your team
When preparing to build a single storey extension, it pays to commission professionals with plenty of experience and a flair for this particular type of work. You should aim to employ architectural designers who are also Planning Specialists, plus those who can provide a Project Management Service as well.
At Divi Design we are proud of our good reputation in all these fields. We are specialists in working with London housing stock in all its idiosyncrasies. We know the London boroughs and their Planning policies well. We have excellent professional relationships with Planning Officers across the city and an outstanding track record with Planning Applications and on guidance around Permitted Development.
Most of all, we take great pride in every job we undertake. Each project is unique and it gives us real pleasure to take a ground floor extension from start to finish, knowing that our work helps make lives as well as houses better, for now and for the future.
We do house extensions all over London. Areas include (but are not limited to): Barking & Dagenham, Bromley, Barnet, Bexley, Enfield, Greenwich, Hammersmith & Fulham, Havering, Romford, Thurrock, Twickenham, Waltham Forest, Wandsworth, Walthamstow, Richmond, High Wycombe, Harrow, and Ealing.
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