CLASS D:- The erection or construction of a porch outside any external door of a dwellinghouse.

To you and I this means external ground floor porch extensions.   There will be exceptions but this is what it means to most people and extension projects. The Legislation breaks this down into several classifications that at first hand appear fairly generous but it is not until you read the restrictions, it becomes clear that there are some very definitive constraints. 

The Governments approach in their wording is to tell you with a very 'broad brush' what your are allowed to build & then want to install the 'masking tape' to define the areas where the 'broad brush' can only be applied.

We will not repeat the wording of PD legislation here as you can read it for yourself elsewhere on this web site. 

Class D permits porch extensions outside existing doorways.  The dimensional constraints are quite tight so the final porch erected under PD will in fact be quite small and may look ill proportioned on a larger dwelling.

PD porches will probably prevent the usual householder requirements requirement for a cloaks room or decent hanging space.

The existing door must remain and all dimensions are external.  Our personal view is that a well designed porch processed through formal Planning Permission will probably result in a nicer looking extension than a PD compliant small blip resembling a guards shelter at London Palace.

A porch does not have to have sides or a front or be enclosed with its own door. It can simply be just a roof or canopy in which case its ground area is the plan view of the roof or the area vertically under the roof.

3M high is not that great for the inclusion of a pitched roof & is measured above the highest natural & adjoining ground level point.

Another limitation regarding its distance from a curtilage boundary with a highway means that it must be at least 2M away.