What are permitted development rights?

As a homeowner, you can carry out certain types of work on your house without the need for planning permission. These are called ‘permitted development rights’.

Any building work done within permitted development will need to meet certain standards and criteria limiting the maximum size of extensions and loft conversions.

Luckily, these limits are quite generous. There’s a lot you can do to maximise your living space and improve your home without the need to go through planning permission.

In this Ultimate Guide, we’ll be taking a look at what home extension and renovation projects you can do under permitted development rights in England.

Development rights in devolved nations

Development is governed by parliament rather than local authorities, and different rules apply in each of the devolved nations – you can check what permitted development rules apply in your area using the links below:

Small kitchen extension

Using your homes permitted development rights means you don't have to go through planning permission for small changes that can have a big impact. Kitchen extension by FMB member Forest Lofts Ltd, London.

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What can I do under permitted development rules?

Limits apply which will restrict both the size of your extension and its outward appearance. This is because permitted development comes with a strict set of rules to make sure developments are in keeping with the local streetscape. They also make sure there’s no negative impact to your immediate neighbours – so your new extension or conversion doesn’t block their light, for example.

Here's a list of the rules that apply to permitted development projects in England:

Rear extensions

This covers any extension across the rear elevation of your property. From side-return extensions to extensions that span the full width of your house.

Maximum depth:

Single storey rear extensions can come out by up to 3 metres for semi-detached, terraced and link-detached houses, and by 4 metres for a detached house, based on the original plans of the building, or as it stood on 1 July 1948 if older.

You can apply for prior approval for rear extensions up to 6 metres for semi-detached, terraced and link-detached houses, or by up to 8 metres for a detached house. This needs to be done before work starts. Your local authority will consult with your neighbours and decide whether prior approval is required before work can go ahead. Factors that can influence their decision include your neighbours’ ‘right to light’.

Maximum height:

No more than 4 metres. Any part of the roof falling within 2 metres of your neighbours’ boundaries must be a maximum height of 3 metres.

Maximum area:

Rear extensions must not come out further than the side of the house, and you can’t cover more than half of the land around the original dwelling (including outbuildings and sheds). The extension also must not come within 7 metres of the rear property boundary.


Your choice of materials must be similar in appearance to the original house.

Total Solutions Group UK Total Build - MBA 2021 - Foundations kitchen rear extension.jpg
Obtaining prior approval can grant extentions of up to 8 metres for a detached house. Project and photo by Total Solutions (Group UK) Ltd t/a Total Build.


Two storey extension

If you need extra bedroom space, you might be surprised to hear that a two-story extension may be perfectly achievable under permitted development. Here’s what you need to know:

Where can you build?

Two storey extensions can only be built off your property’s rear elevation, but not the side or front elevations.

Maximum depth:

You can extend a maximum of 3 metres from rear elevation on semi-detached, terrace or link-detached house, or up to 4 for a detached house.

Maximum height:

The height of the roof ridge and eaves can’t exceed the height of the ridge and eaves on the original house. Any part of the roof falling within 2 metres of your neighbours’ boundaries must be a maximum height of 3 metres.

Maximum area:

The extension (including any existing extensions and outbuildings) can’t exceed more than 50% of the total land around the house.


The pitch of the roof should be the same style as the existing roof and tiles and other externals materials should match. The pitch of the new roof should also match the existing house. Any second storey windows must be obscured glass and their opening parts must be at least 1.7 metres above the floor.

Double height extension by FMB member Interprove Ltd
Double height rear extension on a semi-detached property, completed by FMB member Interprove Limited, Buckinghamshire.



Side extensions

You can add extra downstairs living space to your house with a side extension. However, two storey side extensions don’t fall under permitted development rules. Let’s take a look at what’s achievable without going through planning permission:

Maximum width:

Side extensions must not exceed half the width of the original house.

Maximum depth:

The side extension can extend out further than the back of the house, projecting into the back garden by up to 3 metres for a semi-detached, terraced or link-detached house, or 4 metres if detached, based on the original plans of the building, or as it stood on 1st July 1948 if older.

Maximum height

The highest point of the roof can’t exceed is 4 metres. Any part of the roof falling within 2 metres of your neighbours’ boundaries must be a maximum height of 3 metres.

Property boundary:

There’s no restriction to how close you can go to the boundary with your neighbours, although it is always wise to talk to them about your plans first.

Wrap around:

Full width wrap around extensions aren’t allowed under permitted development rights. But a partial wrap around is permitted, provided the total width of the extension at its widest point does not exceed half the width of the original building.


Your choice of materials must be similar in appearance to the original house.

Loft conversions

There are a few different types of loft conversion. These include:

  • Roof lights only – this is the most straight forward option, which usually this involves interior changes only, with the simple addition of Velux-style windows to the existing roof
  • Dormer conversion
  • Hip-to-gable conversions
  • Mansard conversions
  • L-shaped

One or more different types of loft conversion can be used in a single project (for example, dormer windows can lend extra head hight to mansard or hip to gable conversions). The following regulations apply to them all:

Street view:

Dormers can’t be built on the front elevation of the house under permitted development (this is usually the side that faces the street). The only change at the front can be rooflights (Velux-style windows) which can project up to 15cm from the roof surface.

Maximum height:

Loft conversions can’t be higher than the highest point of the current roof.

Maximum volume:

The total increase in roof volume can’t exceed 50 cubic metres for a detached or semi-detached house, or 40 cubic metres for a terrace. Dormers must be set back a minimum of 20cm from the eaves.


The loft staircase must have at least 2 metres head height clearance.


New windows on the side of the house must be frosted and their opening parts must be at least 1.7m from the floor. Balconies or verandas are not permitted, but Juliet balconies that have no platform are allowed. New roof tiles and windows must match existing.

If you’re ready to extend into your roof, read our ultimate guides to loft conversions and party wall agreements

Dormer loft conversion
Dormer loft conversion project by FMB member Master Builder York Builder Ltd, North Yorkshire.



Garage conversions

If you’re planning to extend into your garage to create a bedroom or living area and most of the work will be internal, it should be achievable under permitted development rules. When replacing your garage door and installing new windows, you’ll need to take care to use similar materials to the existing house.

Where planning permission would need to be considered is if you’re converting the garage into a separate dwelling (including annexes for family members) or increasing its footprint.

It’s also worth noting that permitted development rights for garages may have been removed from some new-build properties and in some conservation areas it may be worth checking with your local authority’s planning department before making any changes.

If you want to get started on converting your garage, check out our ultimate guide to garage converisons for some useful tips.

Porches, garden rooms and outbuildings


No extension can come forward past the line of the principal elevation – that’s usually the side of the house that faces the street. For example, you can’t add a new bay window without going through planning permission.

The only permitted development allowed on the front elevation is a porch with a maximum footprint of 3 square metres and no more than 3 metres in height. It must also be set back at least 2 metres from the boundaries of your property and from the road.

Garden rooms and outbuildings

Garden rooms are classed as ‘outbuildings’ and can be built under permitted development rules. The rules for outbuildings cover structures that are within your property boundaries but not attached to your house. This includes garages, summer houses, and sheds, as well as less obvious buildings like tennis courts, swimming pools, ponds and containers used for heating oil.   

Cumbrian farmhouse with new porch
Adding a practical porch can be done under permitted development. Project by FMB member J C Building Services, Cumbria.



Outbuildings can’t be built more forward than the front elevation of your property (the front wall of your house).

Maximum height:

They can be up to 4 metres high if they have a dual pitched roof, or up to 3 metres with other types of roof, eg a flat roof.  Any part of the roof falling within 2 metres of your neighbours’ boundaries must be a maximum height of 3 metres.

Maximum area:

The outbuilding must not exceed more than half of the original footprint of your house when it was built or on 1 July 1948, if it was built before then.


Decking around your outbuilding is fine, but you cannot build verandas or raised platforms above 0.3 metres in height.

Designated areas and protected buildings:

In National Parks, Areas of Outstanding Natural Beauty, the Broads and World Heritage Sites, the maximum area covered by all outbuildings that are more than 20 metres from the house is limited to 10 metres.

If you’re on designated land, any outbuildings to the side of your house will need to go through planning permission.

External render and cladding rules

Updating the external appearance of your house with render or cladding is usually allowed under permitted development rules, provided the materials you use are of a similar appearance to those used in the original construction of your house.

However, altering the outer fabric of your home can impact both its safety and its thermal insulation properties – which means you will need to obtain a building regulations certificate if:

  • More than 25% of an external wall is re-rendered, re-clad, re-plastered or re-lined internally
  • More than 25% of the external leaf wall is rebuilt
  • If you’re adding cavity wall insulation (formaldehyde gas emissions will need to be checked)

It’s important to note that cladding needs to meet fire safety standards, and you may need to upgrade the thermal insulation performance of your walls to meet building regulations.

To obtain a building regulations certificate, submit either a building notice or full plans via the Planning Portal before any work begins.

If you’re planning to change the appearance of your home with render or cladding, or you live in either a listed building or designated area, then you will need to submit an application for planning permission.

Change of use – business to residential

If you want to dip your toes into the world of property development, Class MA (‘Mercantile to Abode’) may be of interest. This piece of legislation made waves in 2015, making it easier to convert empty Class E commercial premises, such as offices, restaurants, shops and gyms into new homes without planning permission. These still need prior approval from the local planning authority and need to meet certain criteria including:

  • The floor space isn’t over 1,500 square metres.
  • The property must have been Class E for at least two years before your application, and empty for at least 3 months.
  • It must not be a listed building, scheduled monument, in a National Park or Site of Special Scientific Interest or other designated areas (although it can be within a conservation area – rules apply).
Class E premises include:
  • Most retail (excludes some smaller shops in isolated areas that sell ‘essentials’)
  • Offices, financial and professional services buildings
  • Restaurants and cafés
  • Doctor’s surgeries, medical centres, creches and nurseries
  • Indoor sports and recreation centres

Building a new storey or flat

Another option that’s perhaps more geared towards developers or those quite literally ‘thinking outside the box’ is the possibility of using permitted development rights to add a whole extra floor, or even two, to your property. There’s the option of increasing the existing living space or building a separate flat on the roof of your building.

What’s achievable depends on several factors, including the use of the original building (whether it’s residential or commercial) , so it’s advisable to speak to either an architect or consultant on the matter before starting to plan. The general rules that apply are:

  • If the existing building is detached and multi-story, you can add two additional storeys on top. (Existing accommodation in the roof space of the existing house, including a loft extension, is not considered as a storey.)
  • The total maximum height of the building must not exceed 18 metres.
  • If the building is part of a terrace, the extension can’t be more than 3.5m higher than the next tallest terrace.
  • Windows on the side elevation or the sides of the roof are not permitted.


Before you go ahead

Whilst the information above gives you an indication of what can be achieved when you use permitted development rights, it doesn’t replace the need to check the guidance from your local authority planning department – to make sure you’re following the regulations and processes that apply for your property and the area you live in. You can start your conversation by visiting the Planning Portal.

What can’t be done under the rules of permitted development?

There are some situations where you will need to submit an application for planning permission. You can read more about the planning process in our ultimate guide to planning permission, or visit the Planning Portal website. Permitted development rights do not apply to the following buildings:

Flats and Maisonettes
For example, if you want to convert the loft in your top floor maisonette or add an extension to a ground floor flat.

Houses in designated areas
More restricted permitted development rules apply to what planners refer to as ‘designated areas’. These include:

  • Conservation areas
  • National parks
  • Areas of Outstanding Natural Beauty (AONB)
  • World Heritage Sites
  • The Norfolk or Suffolk Broads

Local authorities also have the right to limit permitted development rights for certain areas by issuing an ‘Article 4 direction’ – which refers to Article 4 of the GDPO. This might happen for instance, if they want to preserve the character of an area. 

Some newer homes
Occasionally, newer houses will have their permitted development rights removed as a condition of planning consent when they are built.

Listed buildings
Different rules apply, and you’ll need to obtain listed building consent.

If you’ve used up your permitted development rights
Buildings that have already been extended may have used up part or all of their permitted development rights during their history. You can extend your home more than once, but the total size of all extensions added to the original building as it stood on 1 July 1948 (the date modern planning regulations were introduced) can’t exceed the current limits.  

Wrap-around extensions
This popular type of extension is not covered by permitted development rights due to their large size. However, a side-extension can partially wrap around your house under certain circumstances.

Terraced property extended twice
If your property has already been extended, it may still be possible to extend again under permitted development rights. Loft conversion project by Mitre Peak Lofts Ltd, London.



How do I comply with permitted development rules?

Using permitted development rights doesn’t remove the need for paperwork – you still need to demonstrate the extent of your build and provide plans to your local planning department. You’ll also need to obtain the following documents to sign off your building work:

  • Building regulations certificate – applies to all buildings.
  • Party wall agreements – if your property is not detached.
  • Right to light report – from a surveyor, If your neighbours are concerned that your building work may block their light.
  • Build Over Agreement – from your local water authority, if you’re building near a sewer.

Lawful Development Certificates

It’s also a good idea to obtain a Lawful Development Certificate. Although not compulsory, this can be a helpful document to have if, for example, you need to sell your property and prove that the building work you’ve done meets planning regulations.

You can apply online for a Lawful Development Certificate via the Planning Portal. You’ll need to submit drawings for your council to consider, and an application fee applies. You can usually expect to receive your certificate within 8-10 weeks. You’ll need:

  • Drawings of the existing building – Showing what the property looks like before work starts.
  • Drawings of the proposed building – Showing what the property will look like with the new extension.
  • Site Plan and Location Plan – So the council can find your property on a map and check what regs apply in your area.
Architect plans
Building plans are needed to obtain a Lawful Development Certificate.

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