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Do I need planning permission for a single storey extension?

In many circumstances, rules known as ‘permitted development’ rights allow you to extend a house without needing to apply for planning permission, providing specific limitations and conditions are met. If you want to exceed these limits and conditions, then it is likely that an application for householder planning permission will be required.

The limits and conditions for building an extension under permitted development rules are covered in our guidance on the Planning Portal, and there are other points to take into consideration.

Visit Planning Portal to find out more.

Common Questions

What size extension can I build without planning permission?

In many circumstances, rules known as ‘permitted development’ rights allow you to extend a house without needing to apply for planning permission, providing specific limitations and conditions are met. If you want to exceed these limits and conditions, then it is likely that an application for householder planning permission will be required.

You can find information about the limits and conditions, prior approval and the building regulations on the Planning Portal by using the links below.  

Read about planning permission for extensions

Read about prior approval for larger single storey extensions

Find out about building regulations for an extension

Can I change my house to a shop with a flat above?

Yes, but this type of conversion will require full planning permission. This is because you’d be changing the use of the ground floor from residential to commercial (typically to a use class such as E), while the upper floor would remain as a residential flat (Class C3). The change of use triggers the need for planning approval.  

Find out more about change of use

What is the difference between a roof window and a dormer window?

A roof window (or skylight) is fitted flush within the slope of a roof, while a dormer projects outward, creating additional headroom and floor space.  

Both can be installed under permitted development but must meet specific size and position limits to qualify.  

Also consider building regulations for a new dormer, find out more on Planning Portal  

What size porch can I build without needing building regulations approval?

Building a porch at ground level and under 30 square metres in floor area is normally exempt from the need for building regulations approval.

This is provided that glazing and any fixed electrical installations comply with the appropriate sections of building regulations.

To find out more about the building regulations for porches, visit Planning Portal.

Find out more about glazing and electrical installations

Do i need planning permission for a garden gazebo or adding an awning to my house?

A garden gazebo or freestanding awning will often fall under permitted development rights provided it abides by the restrictions set out by government. In this instance a garden gazebo or freestanding awning will be classed as an outbuilding and should not be in front of the house or more than 2.5 metres in height.

Different rules apply if the awning is attached to the house itself. It may still be permitted development, but falls under the class of enlargement, improvement or alteration.

Read more information including the full list of rules for outbuildings

Read further guidance on extensions.

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