Planning Policy

Extension in North Hertfordshire

Do you need planning permission for a single-storey extension in North Hertfordshire? Here is what the permitted development rules say, how North Hertfordshire District Council’s designations change them, and what decides an application, grounded in the official guidance and quoted verbatim.

Modern glazed extension against a classical stone house
New glass against old stone: the extension question every authority weighs
The short answer

Do you need planning permission for a single-storey extension in North Hertfordshire?

Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed. In North Hertfordshire this matters: the borough has 44 conservation areas, and inside those the permitted development route narrows or is removed, so a single-storey extension can need a full application where it would not two streets away.

1.0: The permitted development position

The starting point

Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed.

“This provides permitted development rights for the enlargement, improvement or other alteration of a house.”PD technical guidance, Class A · full text in the library → · official source →
2.0: What changes it in North Hertfordshire

How North Hertfordshire’s designations apply

Designation in North HertfordshirePublished
Conservation areas44
Article 4 directions (PD removed)0
Listed building outlines0

Because extension depends on permitted development rights restricted on article 2(3) land, the conservation areas above are decisive: inside one, expect to need a full application. Counts are read live from planning.data.gov.uk; your report checks them against your exact address.

3.0: How it’s decided

What North Hertfordshire weighs

Where an application is needed, design does the deciding: depth against the neighbouring rear walls, loss of light, roof form, and materials against the parent building.

Read the full extension guide →

4.0: A worked example

See a single-storey extension in a real report

London’s most common project: a kitchen extension behind a Victorian terrace in a conservation area with an Article 4 direction. 262 nearby decisions, 81% approved.

Read the rear extension in clapham case study →

Your report

Get a planning report for your North Hertfordshire address

A Planning Policy report reads the designations on your exact North Hertfordshire address, quotes the North Hertfordshire District Council and national policies that apply to a single-storey extension, and (on Pro) shows decided applications nearby with outcomes.

5.0: Questions

Extension in North Hertfordshire, answered

Do I need planning permission for a single-storey extension in North Hertfordshire?
Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed. In North Hertfordshire this matters: the borough has 44 conservation areas, and inside those the permitted development route narrows or is removed, so a single-storey extension can need a full application where it would not two streets away.
Does a conservation area affect a single-storey extension in North Hertfordshire?
Yes. extension relies on permitted development rights that are restricted on article 2(3) land, which includes conservation areas. North Hertfordshire District Council has 44 of them, so inside a boundary you are more likely to need a full application.
How does North Hertfordshire decide a extension application?
Where an application is needed, design does the deciding: depth against the neighbouring rear walls, loss of light, roof form, and materials against the parent building. A Planning Policy report quotes the specific North Hertfordshire District Council Local Plan and national policies that apply, verbatim, and shows decided applications nearby.
6.0: More for North Hertfordshire

Other projects in North Hertfordshire