Principal elevation: how do I identify it?

 

The phrase principal elevation appears throughout householder permitted development, but it is not defined in the GPDO itself. The Government’s householder technical guidance explains how it should normally be identified.

For example, Part 1 Class A does not permit an enlargement which would extend beyond a wall forming the principal elevation of the original dwellinghouse. Similar principal-elevation tests appear for roof enlargements, outbuildings and some other permitted development rights.

The principal elevation is often the front elevation facing the main highway, but not invariably. The design and setting of the house matter, and on difficult or corner plots the answer can be a matter of judgment.

 

 

In very simplistic terms the principal elevation means the front of the house. Whilst for many this might be the wall that faces the road, it could well be the wall to the right or left.

The Government guidance says that, in most cases, the principal elevation is the part of the house which fronts the main highway serving it and usually contains the main architectural features, such as bay windows or a porch serving the main entrance. Usually, but not exclusively, it will be what most people understand to be the front of the house.

The front door is therefore a useful clue rather than a legal test. A house can have its main entrance on a side elevation, and unusual orientation, corner plots or historic alterations can make the answer less obvious.

The guidance also confirms that there is only one principal elevation, although that elevation can comprise more than one wall where the frontage is staggered, L-shaped or includes projecting features.

 

Clues as to the principal elevation

 

Look for items such as:

• which elevation fronts, directly or at an angle, the main highway serving the house
• where the main architectural features are concentrated, such as bay windows, a porch or formal entrance treatment
• the position of the main entrance, while remembering that a front door can sit on a side elevation
• the historic design and orientation of the original dwellinghouse
• the relationship between the house, its boundaries, access and surrounding roads
• on a corner plot, which elevation has the stronger character of the principal frontage

No single clue is necessarily decisive. The question should be approached from the overall design and setting of the house, using the Government guidance rather than assuming that the driveway, postal address or current front door settles the issue.

 

 

What if I have a road to the rear or a footpath to the front?

 

You may have read that the principal elevation is the one facing the road. In many cases this is true, but not always.

Newer layouts can make the relationship with the highway much less obvious. A house may face a footpath, green or shared space while vehicular access runs to the side or rear.

In those situations, do not simply nominate the elevation nearest the road. Look at the original architectural composition, the formal entrance and the way the dwelling was designed to address its surroundings. A rear service road does not automatically make the rear wall the principal elevation.

 

 

Corner plots and two road frontages

 

A corner plot can have two elevations facing highways, but that does not create two principal elevations. The Government guidance recognises that a judgment may be needed where more than one elevation has the characteristics of a principal frontage.

Look at the original design of the dwellinghouse, the formal entrance, architectural composition, relationship with the roads and the way the house was intended to address its surroundings. A side road becoming busier over time does not automatically turn the side wall into the principal elevation.

 

Principal elevation and a highway-facing elevation are not the same test

 

Some permitted development rules refer specifically to the principal elevation; others also contain separate restrictions where a wall or roof slope fronts a highway. Those tests should not be collapsed into one another.

For example, a house can have a side elevation facing a highway without that side becoming the principal elevation. On a corner plot this distinction can decide whether a proposed extension, roof enlargement or outbuilding falls within permitted development.

 

Still need help?

 

If the principal elevation is difficult to identify, historic photographs, original plans and earlier planning records can be useful evidence. This is particularly important where the GPDO test refers to the principal elevation of the original dwellinghouse. Under the GPDO, ‘original’ means the dwellinghouse as it existed on 1st July 1948, or as first built if constructed after that date.

That does not mean every question about principal elevation can be answered by freezing the present appearance of the house at 1948. The statutory test must be applied to the original dwellinghouse identified under the GPDO, and the principal elevation is then assessed by reference to its design and setting. Later extensions do not themselves rewrite what counts as the original dwellinghouse.

There is only one principal elevation, although it can comprise several walls facing broadly the same direction. Where two elevations compete for that status, the Government guidance expressly recognises that a judgment has to be made.

Reach out and book a Zoom session if you need further help or clarification. It is important to understand which is the principal elevation in order to take advantage of the GPDO and other legislation.

In case someone misspells the word, principle elevation will also end up here 😉

 

 

 

Page Updated: 2nd September 2026

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