Permitted Development Extensions - Oct. 1st
Extensions for permitted development to domestic dwellings fall under class A of the GPDO in most
cases. There is other criteria for extensions to a dwellings roof for example but this section will simply
concentrate on permitted development for home extensions.
The PD rules have changed from a building volume or area based assessment to a more impact
based assessment which now has dimensional limits one can extend a property usually from the original rear or side
elevation of the existing dwelling house wall.
This combined with eaves & roof heights limits & minimum distances to boundaries make for a more
reasonable assessment of what the permitted development rights are for extensions. This does allow greater freedoms
for people who wish to install extensions to their properties without the need for Planning Permission but the
dimensional limits and physical size of what you can do under the PD rules needs to be fully understood.
Another major trap that can make your extension fall outside of the Permitted Development allowances is the fact
that the 4M & 3M maximum projection distances for single and two storey extensions relate to the ‘original’
house wall. Therefore if you are intending to extend from a previous extension wall no matter how old, then you
will probably fall outside of the PD rules and require formal planning consent.
Side windows on the upper floor the permitted development extension are also prevented unless they are obscure
glazed and any opening sash must be at least 1.7M above the floor level which is a new restriction compared to the
previous permitted development rules.
Download a pdf guide for Permitted Development on domestic
guidance on permitted development and domestic extensions
The concise and detailed criteria of the permitted development wording for domestic extensions can be located
elsewhere on this web site.
As always, you are advised to obtain professional drawings completed by a Building Designer which can be used as
part of a formal Certificate of Lawful Development application to the Council that will formally and legally
confirm that your project is indeed permitted development.