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A beginner’s guide to home extensions

Words from Charlie Mills – Head of Oakwrights’ Country Buildings & GreenRooms divisions


Where do I start with my new extension?

When deciding to extend your home, it is an exciting opportunity. You will have a reason for wanting to extend, anything from wanting to expand your kitchen/dining area, to making the most of a view. So, it’s important to think about the current space and what it’s missing.

Sketching out floor plan ideas is an exciting task that can help inspire you. Depending on what you want to achieve, look at your new space as a blank canvas, ignore what is already there as it may put hurdles in front of great ideas.

When you have an idea of the size and space, then consider the external shell you want. Don’t be blinkered by the external finish of your existing property, you can extend without having to use the same materials. For example, adding an oak frame to a brick/ stone/ rendered property can complement your home adding a ‘wow’ factor rather than clash.


Do I need an Architect when extending my home?

When putting designs together, you don’t always need an architect. For standalone extensions, companies who produce conservatories, garden rooms and orangeries will have design consultants who will assist you on your design journey and can submit the design into planning for you.

These companies will have specialist knowledge. For example, when choosing an oak frame, there are guidelines to make the most of your design. E.g. spans over 7m are harder to achieve in one span, so posts may be required which will influence your design.

For traditional construction such as brick and block extensions, getting an architect on board will allow you to produce design and details for your chosen construction teams to follow as there is no single company taking responsibility of the shell.

What are the planning considerations I need to think about? – what’s allowed under permitted development rights?

Like with any addition to your home, it is important to understand what planning laws might be required. However, when deciding on an extension you may fall into a category called ‘Permitted Development’. This allows you to extend your home, under certain criteria, without seeking planning permission. To understand this more in the context of your own project it’s always worth doing some research on the Planning portal website, or if you are already talking to a company about working on your extension its worth checking with them as they will be able to help give you some guidance.

The planning portal has a very good infographic explaining permitted development that many of our clients have found useful but some of the general takeaways from this are:

Permitted development applies if:

• You are building on less than 50% of the land around your existing property
• You are not building higher than the tallest part of your existing roof
• The height of a single storey extension is 4m or less
• You are not extending beyond the rear wall of your existing house by more than 3m of an attached house and 4m of a detached house with a single storey extension
• You are not extending more than 3m beyond the rear wall of the existing property if more than single storey

To view the planning portals infographic click here 

If building on or near to designated land, (for example areas of outstanding natural beauty and National Parks), there are tighter restrictions to extending your home under ‘Permitted Development’. You are also not eligible for Permitted Development for any extension other than a single storey rear extension of no more than 3m if you are in a Conservation Area.

If you do fall into a designated land or conservation area, we would highly recommend that you gain advice from someone who has knowledge in this field and can talk to you about your specific project.


How do I get my extension built?

Once you have decided on your method of construction, worked out your budget and gained costs for the project and been granted planning/permitted development rights. It’s time to get started.

You will need to take on a builder to carry out the groundworks for your extension and to join your existing property to the new extension. If working with a company who is producing the external shell such as a timber frame company, they will take on most of the envelope from internal structure, stud walls, joinery and roofing. You can work closely with your builder to install the materials you have chosen and all the finishes to take your vision and bring it to life.