Professional Architects and Designers in Solihull Est. 1981

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What can I build without planning permission?

Posted in Top Tips | Written by Vicki Potter

Permitted Development Rights

There are a set of standard rules that allow most homeowners to do specific work to their property without the need for planning permission. This is called your Permitted Development Rights.

Some properties have had their Permitted Development (PD) Rights removed meaning you will need planning permission for any change – this is common on new housing estates, new houses in the Green Belt, barn conversions and conversions from commercial buildings. Flats and maisonettes don’t have Permitted Development Rights. The rules are also different for Listed Buildings and in protected areas such as Conservation Areas, Areas of Outstanding Natural Beauty, National Parks or The Broads.

It is always best to check with your Local Authority to confirm if your home has Permitted Development Rights or not.  

Green Belt

What you are allowed to build with planning permission and under Permitted Development are totally different things. There are instances, particularly in the Green Belt, where the Council will not give you planning permission for an extension but you may still be able to enlarge your house using your Permitted Development Rights.

Permitted Development pitfalls

For houses with Permitted Development Rights in tact, you can generally build rear extensions, single storey side extensions, porches, loft and garage conversions and add flues, CCTV, solar panels and EV chargers. You can also change windows and doors, erect fences and enlarge your parking area. However, there are many limitations and restrictions for each of these types of work. It is important to always check all the details.

I was on site recently and had to tell a new client that the extension he had recently built, believing it to be Permitted Development, did not comply with the rules and therefore required planning permission. This is not the first time I have had to do this.

So to avoid you having the same issues, here is my overview on single storey rear extensions. I will follow up with more tips detailing the other type of extensions and alterations over the next few months.

Single storey rear extensions

Also known as Class A extensions

Single storey rear extensions can be up to 4m deep for a detached house and 3m deep for attached houses.

The first and most important thing for a rear extension to be considered Permitted Development is that it must be built off the original rear wall of the house. ‘Original’ means the house as it stood on 1st July 1948. If you have any steps in the rear wall that the extension will wrap around, it will be considered a side extension as well as a rear extension. This applies to an original bay window or chimney breast too.

If the extension is deemed a side extension as well as a rear extension, it cannot be wider than half the width of the original house. If your front door does not face the road, it is not always obvious which wall is the ‘rear’ or ‘side’ wall.

The new extension cannot generally abut a previous extension. It is possible to have an extension that is part rear and part side extension, but only if it follows the rules shown above. 

There’s more….

A pitched roof extension can be up to 4m high. The eaves can be no higher than 3m if you are close to the boundary. This means in the case of a flat roofed extension, the flat roof cannot be taller than 3m. These heights are taken from the natural ground level at its highest point. If you live in a bungalow, the eaves and ridge height on the extension cannot be higher than on the main house. The roof pitch should match the existing roof where practical.

The total combined area of the outbuildings, previous extensions and new extension cannot be larger than 50% of your garden area. The extension cannot face a highway, which may impact you if you live on a corner plot. The extension cannot have a balcony, verandah or flue.

The materials must all match the rest of the house.  This includes the windows and doors. If your extension has grey bifold doors, for example, and the rest of the house has white windows, it is technically not Permitted Development.

Certificate of Lawfulness or

Lawful Development Certificate

The rules can be open to interpretation between Local Authorities and there are lots of subtle reasons why your proposed extension may not be deemed Permitted Development. We work with the Permitted Development rules every day, and still find that on some properties, it can be difficult to establish whether your proposals would fit the rules or not.

For this reason, we would always advise you take professional advice and /or apply for a Certificate of Lawfulness (also called a Lawful Development Certificate) from your local Planning Department. This is a certificate confirming that your proposals comply with the Permitted Development rules and you can proceed without planning permission. This is invaluable not only for your own peace of mind, but it proves your have done everything legally when you sell the house. Your Council will charge £103 for this certificate.

Prior Approval for larger home extensions

There is a  further rule allowing you to build single storey extensions at the rear of your house up to 8m for detached houses and 6m for attached houses, subject to there being no objections from the neighbours. This is called Prior Approval. Instead of obtaining a Lawful Development Certificate, in this instance, you MUST notify the Council before work starts via a Prior Approval application. The Council will then tell your neighbours and confirm back to you in writing that you can proceed within 42 days.  Whilst a Lawful Development Certificate is not a legal requirement, following the Prior Approval process is.

Get your paperwork in place

If your house is in a Conservation Area or other area of scientific interest such as Areas of Outstanding Natural Beauty, National Parks or The Broads, no side extensions are allowed under Permitted Development. You are also not allowed to carry out a larger single storey extension using the Prior Approval process. If your house is Listed, you will still require Listed Building Consent to extend.

In all cases, regardless of the need for planning approval, Building Regulations approval is required for extensions to your house.

The Government produce a ‘Permitted Development Guide for Householders :Technical Guidance‘ booklet which is very helpful.

If you need further advice and are based in our local area, please feel free to get in touch for an initial consultation.


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