House extension rules UK - Planning or PD?

The rules governing house extensions fall into two camps.  Those that are affected by formal planning permission and those that are built under permitted development (PD).  Both are entirely at opposite ends of the house extension rules.

When a house extension requires formal planning permission, the scheme proposal will be assessed by the Case Planning Officer against the councils current planning policy and design guides.  Some of these house extensions rules are in fact not rules at all but deemed to be guidance in most cases.  However, as the years pass by planning policy has become more and more prescriptive where the guidance is interpreted as rules by the junior case planning officers who lack the experience of real world issues.

If I was to sum up most relevant planning policy applicable to house extensions that could be seen as rules affecting house extensions, these the following would probably suffice as a generic guide.  As with all planning guidance the issues are very subjective and one mans design icon is another monster:-

• Extensions should be subordinate to the main house, be in scale, respects the character of the original dwelling & surrounding area.
• Extensions must not have an overbearing impact upon the street scene & the adjoining neighbours.
• The extension must not have any adverse overlooking issues & must not interfere with important light angles from the middle of the neighbours windows.
• A one metre min. gap to the side boundary must be maintained at the first floor level to prevent the ‘terracing’ effect of extended properties.

The other aspect of house extension rules for permitted development (PD) are entirely different and cannot be deemed as guides.  For a home owner to erect a house extension safely without planning permission then the PD restrictions or criteria must be wholly adhered to.  Any deviation will render the house extension illegal or require retrospective planning permission.

Stating all the rules for a PD compliant house extensions here would take another web site to explain it all fully sop we will leave that for another day.  Suffice to say the rules concerning house extension are full of trip wires and all homeowners are advised to have properly prepared plans for use within a Certificate of lawful development application to the planning department before they start on site.  Without such a legal document from the council you run the risk of falling into a technicality trap.