From 30th May
2013 changes to the Permitted Development Rules came into force.
These rules doubled the
previous allowances so you can now build up to 8 metres deep for single
storey rear extensions to detached houses, and up to 6 metres deep for terraced
and semi-detached houses or rear extensions of more than 1 storey
to detached houses.
Confusingly however, a
homeowner wishing to build an extension greater than the existing Permitted
Development limits (see below) must first write to the local planning
authority providing plans and a description of the proposal. The local
authority will then notify adjoining neighbours who will have 21 days to make an
If no objection is received the homeowner will be able to proceed.
If any neighbour raises an objection, the
local authority will then consider whether the impct of the proposed extension
on the amenity of the neighbours is acceptable. No fee will be payable.
The second major change
involved allowing the conversion of offices into homes under Permitted
Just to make things even
more confusing, 17 local authorities (mainly in London) were granted exemption to these
new rules, which will not apply in their areas.
PERMITTED DEVELOPMENT RULES
EXTENSIONS and CONSERVATORIES
You can build certain types of home extension without having to make a planning application - subject to meeting the rules below. This is known as 'Permitted Development'.
The main difference to the old system is that new extensions are no longer judged in terms of their volume. Instead there are clear rules on their external depth, width and height. But there are still some grey areas, such as defining 'principle elevation' (normally, but not always, the front wall). The rules for conservatories are the same as for extensions.
If your design doesn't meet the following rules, you can of course apply for planning permission.
No extension allowed in front of your ‘principal elevation’ - normally
the front main wall.
No extension allowed where your side wall faces a highway (or where the side is the ‘principle
Must be single
Max height 4m
Max width up to half width of original
Single storey ext 4m for
detached houses (doubled to 8m from May 2013 - see above)
3m for attached houses (semis, terraces etc)
(doubled to 6m from May 2013 - see above)
2 storey or higher 3m including ground floor (doubled to 6m from May 2013 - see above)
Single storey ext 4m
No extension to be higher than the highest part of the main roof.
Eaves and ridge height = no higher than existing house
Extensions within 2 m of boundary
= 3m max
No extension where more than half the area of land around the ‘original house’ * would be covered by
additions or other buildings.
2 storey or higher extensions must be no closer than 7m to the rear
Roof pitch of extensions higher than one storey to match
Materials to be similar in appearance to the existing
No balconies or verandas
Windows to upper floors: side-facing to be obscure-glazed, and 1.7m above floor level
other ‘designated land’*)
No PD for rear extensions of more than one storey.
No side extensions.
No cladding of the exterior.
Not permitted - but you only
need make a single application for Listed Building Consent
* "original house" = as it
was first built or as it stood on 1 July 1948
* Designated land
includes national parks and the Broads, Areas of Outstanding Natural Beauty,
conservation areas and World Heritage Sites.
Click here to see PD planning rules demonstrated on the interactive house