House extension under construction with scaffolding — All Aspects Construction, Cardiff

Extending a house is an exciting thing to plan and a tedious thing to consent. Most of the tedium is avoidable, and almost all of it is decided in the first conversation rather than at the application.

Here is the order we work in, and why that order saves people money.

First: which council actually decides

This sounds like an administrative detail. It is not. The five towns we work across sit inside four different planning authorities, each with its own conservation area boundaries, its own local plan and its own officers.

Town Local planning authority Local detail worth knowing
PenarthVale of Glamorgan39 conservation areas across the Vale, including the urban centre of Penarth, plus an Article 4 direction on certain properties
BarryVale of Glamorganas above — same authority, different conservation boundaries
CardiffCardiff CouncilArticle 4 direction covering Cathays, Roath and Plasnewydd for small HMO conversions
CaerphillyCaerphilly County Borough16 conservation areas
PontypriddRhondda Cynon Tafthe town centre conservation area boundary was enlarged in November 2011

Checking your address against the right authority’s boundary map is a ten-minute job, and it is the one that most often changes the design.

Second: whether you need permission at all

If the scheme fits inside permitted development, there is no application, no fee, no wait. In Wales that means a single-storey rear extension of no more than 4m beyond the original rear wall and no more than 4m high — applied uniformly, with no separate allowance for a detached house.

Be careful what you read. The 6m and 8m figures that dominate UK search results come from England’s Larger Home Extension prior-approval scheme, and Wales has no equivalent. A budget and a programme built around going to 6m without full permission is wrong on both counts.

Third: what a conservation area takes away

Inside a conservation area, side extensions and multi-storey rear extensions stop being permitted development, and a roof extension or dormer is excluded outright. A single-storey side extension is limited to 3m projection with a 1m setback from the principal elevation.

In parts of Penarth it goes further still. An Article 4(2) direction, recommended by the 1994 appraisal and adopted in 1996, removes permitted development rights from alterations most people would never think to ask about:

What a Penarth Article 4 direction removes On certain properties in Penarth an Article 4 direction gives the Vale of Glamorgan Council extra control over minor alterations. Replacement windows, replacement doors and changes to boundary walls require planning permission where they normally would not. The direction was recommended by the 1994 conservation area appraisal and adopted in 1996. Article 4 in Penarth: the small jobs that suddenly need permission Replacement windows including like-for-like Replacement doors the front door counts Boundary walls altering, rebuilding or removing Applies to certain Penarth properties only — check your address against the Vale of Glamorgan’s map before ordering anything. Source: Vale of Glamorgan heritage guidance and the Penarth Conservation Area Appraisal and Management Plan, July 2011.
These are jobs a homeowner would reasonably assume need no permission at all. On an Article 4 property they do — which is why we check the address before anyone orders a window.
New red brick boundary wall — All Aspects Construction, Cardiff
A new brick wall from one of our own jobs. On an Article 4 property in Penarth, rebuilding a boundary wall like this is a planning matter rather than a weekend.

How we work through it

  • First visit and feasibility. We measure, look at access and levels, and check the address against the right authority’s conservation and Article 4 mapping before anything is drawn.
  • Design. We work with local architects to turn what you want into drawings that will actually get consented, rather than drawings you then have to pay to change.
  • The paperwork. Planning where it is needed, building control either way — permitted development is not exempt from building regulations, it only means you did not need planning permission.

If your idea does not fit permitted development and a full application is the sensible route, we will say so at the first visit rather than three weeks in. That is not pessimism; it is the difference between a programme with a start date on it and one without.

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