Definition of permitted development terms.
When the new PD legislation arrived in October 2008, many professions & service providers were taken
'aback' by its apparent lack of clarity especially over some of the definitions.
Many Local Planning Authorities (LPA's) expressed concern at the extra lack of control and the effects of home
owners implementing what appeared to be a very loose charter for uncontrolled development to an existing dwelling
Many LPA's started to deliberately misinterpret all manner of strange things in order to limit, stop or control
schemes that were being presented to them as permitted development.
Whether this was to give Central Government an early warning message that they had got the wording wrong or
to deliberately prevent some homeowners implementing their new wider range of development freedom without
formal Planning Control is unclear.
During the first year of the new PD legislation we were hearing things about Planners deciding that the side of
a pitched roof (commonly known as a verge) was now a soffit for the controlling dimensions.
We had situations of strange measuring points from ground to eaves levels on sloping sites where the lowest
ground level point was taken.
Hopefully, nearly two years on and a host of appeal decisions for reference, we have moved away from the chaos
of misinterpretation by the Planners and certain issues of technical detail has now been resolved.
The new DCLG Technical Guidance pdf is a very useful document and helps resolve 90% of all the
variations / combinations you can have with this new PD legislation but even that guide has some strange
dimensional reference points especially how you measure to a roofs eaves for example. In my mind and
most other architectural & building design professionals, the eaves is to the underside of the soffit board,
not he top of the roof level.
Anyway, it is a start!
Q. What does 'principal elevation'
The term 'principle elevation' is a new phrase introduced within the new 2008 GPDO
for Permitted Development. There has been much debate as to what it means as it should replace the term
'front elevation'. In most cases it will be the same thing. However, there are some houses that have a
very dominant elevation that may not house the front door or even front a highway for example. In some
situations the old term front elevation as most people understand it may not be the perceived principal elevation
A recent appeal case referred to what the average man on the Clapham omnibus would
consider to be the principal or main elevation of a property. There will be some cases where a view will have
to be take that suits your particular development opportunity under PD and then test it with a Certificate of
lawful development through the LPA of the Council.
Fortunately the DCLG Technical Guidance document has confirmed that their can only
be one principal elevation but it could have several faces (between bay windows for example).
Determining what is the 'principal elevation' to your own property is
probably the very first major step is assessing what else you can complete to your own dwelling under
permitted development as the principal elevation sets the orientation of all other elevations for the dwelling
(side & rear).
Q. What is a verge?
This is a wall to roof junction that normally slopes with the angle of the roof.
eg - a gable end wall where it meets with the roof overhang.
Q. What is the eaves?
This is normally at the bottom of a roof slope where it oversails the wall.
It also normally support the gutter.
Q. What does NOT constitute development under
(a) the carrying out for the maintenance, improvement or other alteration of any building of
(i) affect only the interior of the building, or
(ii) do not materially affect the external appearance of the building.
Examples would be re-roofing your house with like-for-like materials. So replacing old tiles with sound second
hand or new matching tiles is not development and therefore cannot require 'permission'.
However, changing the material of the roof covering for an alterative materials (tiles to slates for example)
would probably constitute development but would be allowable as 'permitted development' under PART 1 Class C
meaning that you already have the planning permission to carry them out. Government Circular 9/95 states at para.
42 "Class C....would generally permit the replacement of a roof, irrespective of the materials used..." (excluding
conservation areas which does require a specific planning permission).
Q. What does 'original' mean?
"original" means as the dwelling was on 1st July 1948 or if after that date, as it was first constructed
Q. What does 'existing' mean?
"existing" in relation to any building or any plant or machinery or any use, means existing immediately before the
carrying out of any PD works.
Q. What does 'dwellinghouse' mean?
"dwellinghouse" is not a building containing one or more flats, or a flat contained within such a building.
Q. What does 'height' mean?
Its height when measured from the nearest adjoining natural ground level. Where the level of the surface of the
ground on which it is situated or is to be situated is not uniform (including sloping ground) the level of the
highest part of the surface of the ground adjacent to it.
Q. What is a highway?
A 'way' over which the public have a right to pass and re-pass and will include roads, footpaths, bridleways
and 'footways' (pavements). However, it does not seem to include a river over which the general public have a right
to travel which is strange.