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Whether you’re thinking of getting a kitchen extension, a side extension or rear single storey extension, these can be a great way to add living space to the ground floor of your home. You can create nice feature rooms such as open plan kitchens, dining areas or sun-rooms, to bring the garden into the home. More practical additions can also be added or incorporated, with re-configured layouts such as utilities, studies and downstairs toilets.



Design Considerations

Before beginning your single storey extension plans, there are several things to consider, every design needs to be planned around what you want to achieve, and how best to accomplish this. Once the size and layout of your extension has been determined, site checks should be carried out on any shared boundaries, party wall, mains sewers, and if it’s a listed building or in a conservation area. Not only will we give you the best options, we will go into detail of why you want to build, then talk through how to do it. It is advisable to give us a rough budget so we know what to design to, the last thing we want is to produce a design you love but can’t afford.

Other important things to consider are drainage, your single storey extension roof style, nearby trees, boundaries, access, external impact etc.

Design options for your home extension

Firstly, we will determine the size and layout of your single storey extension based on the practical requirements, such as access, integration and impact on the existing structure. We don’t want to design new spaces that are detrimental to the existing space.  You may have space already available that needs tweaking, which can be altered and re-configured.  We also don’t want you to end up with dark unusable, impractical spaces or a corridor effect.

With the size and layout, we will then explore roof options, tiled mono pitch, dual or ridged, hipped or flat roofs. Then we add the finishing touches with you discussing and displaying options around glazing and the important wow factors. We keep up to date with trends and new material finishes, plus cheaper alternatives that have similar effects.

Most single storey extensions can be built under permitted development, see our guide here. We will give you the necessary advice and where necessary make permitted development enquiries.

Take a look at our gallery of single storey extensions in Hull, Beverley, Hedon, Goole and surrounding East Riding areas.  

single story side extension from CK Architectural
single storey rear extensions
rear single storey garage extension
single storey Rear Extension plans

Planning Permission

In most cases a single storey extension can be built under permitted development (see below) which means it does not need a homeowner planning permission application.

Larger rear single storey extensions over the permitted development measurements can be done on a prior approval application. This is a basically a planning application that’s deemed approved. The council will send notice to any neighbours that share a boundary, and if no reasonable objections are made, its deemed approved.

If you do need planning permission for your single storey extension, there will be an 8-week period once all documents are submitted to the local council.

Here at CK Architectural, our design consultants will advise what type of application is needed and the likelihood of approval. We will check the design against the planning guidance, such as over development, impact on street scene, right of light, over shadowing, loss of amenity and outlook, massing/dominance, loss of privacy, etc.

Take a look at our Planning Permission Guide or the local Planning Portal for more information. 

Permitted Development

A small single storey extension to your home is generally considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:

  • No more than half the area of land around the “original house” would be covered by additions or other buildings.
  • No extension forward of the principal elevation or side elevation fronting a highway.
  • Single storey rear extensions must not extend beyond the rear wall of the original house by more than three metres if an attached house, or by four metres if a detached house.
  • In addition, outside Article 2(3) designated land* and Sites of Special Scientific Interest, the limit is increased to 6 metres if an attached house and 8 metres if a detached house.
  • These increased limits (between 3m and 6m and between 4m and 8m respectively) are subject to the prior notification of the proposal to the Local Planning Authority and the implementation of a neighbour consultation scheme. If objections are received, the proposal might not be allowed.
  • Maximum height of a single storey rear extension of four metres.
  • Maximum eaves height of an extension within two metres of the boundary of three metres.
  • Maximum eaves and ridge height of extension no higher than existing house.
  • Single storey side extensions maximum height of four metres and width no more than half that of the original house.
  • Roof pitch of extensions higher than one storey to match existing house.
  • Materials of new single storey extension to be similar in appearance to the existing house.
  • On designated land no cladding of the exterior.
  • On designated land no single storey side extensions.

Building Regulations for Single Storey Extensions

Most alterations to your home will require a building certificate from a building control body, either from the local authority or a private building inspector.  Once the design and planning has been approved, you will then need a detailed set of drawings and specification that demonstrates the new extension can and will be built in accordance with the building regulations approved documents.  These building regulations drawings will then be submitted for a full plan check, amended if necessary, and once approved will be the standard that your project is to be built to and inspected against.  Our plans will include all the necessary detail such as structure, passage of sound, disabled access, drainage, resistance to moisture, collision, impact, heat loss, ventilation, light, emergency escape and much more.  These drawings will be used when the building control officer inspects the build, to ensure the builder is carrying out the works correctly. 

For more information take a look at our Building Regulations Guide.

Building and Builders

Once you have your detailed drawings approved, CK Architectural’s Services don’t have to end there.  We also offer a Project Management Service where we will oversee and manage every aspect of the project, as well as dealing with any builders on your behalf.

If you decide to project manage the build yourself, we can recommend reputable builders we trust.  We do advise that any quotation you consider, should be written up clearly and thoroughly detailed.  Both you and your builder need to know exactly what is included in the price, or disagreements can occur. We have extensive on-site knowledge and can work closely with you, so we will always advise where we think areas need exploring or issues may arise. We advise that you use our drawings in line with the quotation, and any additional information we don’t provide such as plumbing and electrics is agreed in detail before the first fix goes in, it will be costly changing things once the initial preparation has been built. We offer help throughout for both you and the builder and will come to site if help is required.

Single Storey Extension in Hull

The Cost of a single storey extension

What is the cost to build a single storey extension? This is a question we get asked a lot and unfortunately there is no set answer. The building work will depend on many different factors such as existing structure, roof type, location, choice of materials etc.

However, we can give you the average cost of a single storey extension breakdown to help you budget and plan ahead. Weather it’s a side extension or rear extension the price will be similar.

£1,500 to £1,900 per square metre for basic quality single extension

£1,900 to £2,200 per square metre for decent quality single extension

£2,200 to £2,400 per square metre for exceptional quality single extension


For an average single storey extension of 4m x 5m, the build cost would therefore be £30,000 upwards for basic quality, from £38,000 for decent quality and from £44,000 for exceptional quality. 


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