Editorially checkedVisible ownership, review date and official-source context for this page.
Written by Sam JonesReviewed by UK Planning Guide Editorial Review DeskLast reviewed 11 April 2026Official-source context National planning baseline, local authority context and page-specific tripwires.Verify before spending Stop and verify when the scheme is close to a depth, width or height threshold or depends on the original-house baseline.
Area project hub

House Extension Across Wales

Use this page to compare the local authority layer for house extension across 25 council areas in Wales, find the councils worth checking first and open the rule pages that usually change the answer.

Quick area answer

What This Area Project Page Helps You Decide

Broad read

Area comparison is useful when you are still deciding which council deserves the closer look, not when one exact site is already doing all the work.

What often changes it

Conservation areas, Article 4, listed buildings, local design expectations and the exact dimensions of the scheme can all change the route.

Best next step

Compare the 25 council areas below, then open the local project guide and the rule page that looks most likely to decide the answer for your site.

Decision guide

When This Area Comparison Usually Helps And When You Should Go Straight To A Local Page

Usually enough for a first pass when

  • You are still comparing councils and have not narrowed the project to one site-specific route yet.
  • The uncertainty is about where house extension feels more sensitive rather than whether one exact drawing already works.
  • You want to understand the likely local pressure points before paying for more detailed design work.

Go more local when

  • One council area, one conservation area or one exact property constraint is already doing most of the work.
  • The scheme is close to a height, boundary, roof or visibility limit.
  • You need a reliable route decision rather than a comparison-led briefing.

What usually settles it faster

  • Open the matching local project guide for the correct council below.
  • Pair it with the rule page that looks most likely to block or change the route.
  • If the scheme is borderline, move to measured drawings and written confirmation rather than relying on comparison alone.
Compare by local authority

The Councils To Compare For House Extension

Local project page

Isle of Anglesey

Check the local planning route, restriction signals and next steps for house extension in Isle of Anglesey.

Open local guide
Local project page

Gwynedd

Check the local planning route, restriction signals and next steps for house extension in Gwynedd.

Open local guide
Local project page

Conwy

Check the local planning route, restriction signals and next steps for house extension in Conwy.

Open local guide
Local project page

Denbighshire

Check the local planning route, restriction signals and next steps for house extension in Denbighshire.

Open local guide
Local project page

Flintshire

Check the local planning route, restriction signals and next steps for house extension in Flintshire.

Open local guide
Local project page

Wrexham

Check the local planning route, restriction signals and next steps for house extension in Wrexham.

Open local guide
Local project page

Ceredigion

Check the local planning route, restriction signals and next steps for house extension in Ceredigion.

Open local guide
Local project page

Powys

Check the local planning route, restriction signals and next steps for house extension in Powys.

Open local guide
Local project page

Pembrokeshire

Check the local planning route, restriction signals and next steps for house extension in Pembrokeshire.

Open local guide
Local project page

Carmarthenshire

Check the local planning route, restriction signals and next steps for house extension in Carmarthenshire.

Open local guide
Local project page

Swansea

Check the local planning route, restriction signals and next steps for house extension in Swansea.

Open local guide
Local project page

Neath Port Talbot

Check the local planning route, restriction signals and next steps for house extension in Neath Port Talbot.

Open local guide
Local project page

Bridgend

Check the local planning route, restriction signals and next steps for house extension in Bridgend.

Open local guide
Local project page

Vale of Glamorgan

Check the local planning route, restriction signals and next steps for house extension in Vale of Glamorgan.

Open local guide
Local project page

Cardiff

Check the local planning route, restriction signals and next steps for house extension in Cardiff.

Open local guide
Local project page

Rhondda Cynon Taf

Check the local planning route, restriction signals and next steps for house extension in Rhondda Cynon Taf.

Open local guide
Local project page

Merthyr Tydfil

Check the local planning route, restriction signals and next steps for house extension in Merthyr Tydfil.

Open local guide
Local project page

Caerphilly

Check the local planning route, restriction signals and next steps for house extension in Caerphilly.

Open local guide
Local project page

Blaenau Gwent

Check the local planning route, restriction signals and next steps for house extension in Blaenau Gwent.

Open local guide
Local project page

Torfaen

Check the local planning route, restriction signals and next steps for house extension in Torfaen.

Open local guide
Local project page

Monmouthshire

Check the local planning route, restriction signals and next steps for house extension in Monmouthshire.

Open local guide
Local project page

Newport

Check the local planning route, restriction signals and next steps for house extension in Newport.

Open local guide
Local project page

Bannau Brycheiniog National Park

Check the local planning route, restriction signals and next steps for house extension in Bannau Brycheiniog National Park.

Open local guide
Local project page

Eryri National Park

Check the local planning route, restriction signals and next steps for house extension in Eryri National Park.

Open local guide
Local project page

Pembrokeshire Coast National Park

Check the local planning route, restriction signals and next steps for house extension in Pembrokeshire Coast National Park.

Open local guide
Rule-first route

House Extension Topics Worth Checking Across Wales

Why area comparison helps

How The Same Project Can Feel Different Across One Planning Area

Planning rules for house extension in Wales may start from the same national footing, but the confidence you can place in that footing changes once local designations, property context and authority interpretation enter the picture.

This area hub is there to show where the answer still looks routine, where it tightens up and which council page is worth the deeper read.

Common area-wide tripwires

What Usually Deserves A Closer Look In Wales

Strong next actions

What To Do If You Still Need A Faster Answer

Deeper comparison routes

More Area Comparisons And Related Follow-Ups

Use these only after the local authority route and main next steps above. They are helpful, but they should not compete with the primary answer.

Show more rule comparisons, nearby area hubs and related project alternatives
Broader comparison

Nearby Area Project Hubs

Trust and method

How To Use This Area Project Guide Responsibly

Rules vary by location

Planning routes can change by council area, property history, designations and the exact proposal. Use this page as a structured guide to the next check, not as a blanket approval.

What this page is for

This page helps you compare house extension planning permission guidance across Wales so you can identify which local authority path, rule page and verification step deserve attention first.

What it does not replace

It does not replace the council-specific project guide, the exact property checks or any formal confirmation needed for a borderline scheme.

How the guidance is built

The comparison sits on the same Welsh planning system baseline across the area, then focuses on the local authority differences most likely to change the route in practice.

When to stop relying on broad guidance

Stop relying on area comparison alone once one council, one conservation-area issue, one Article 4 question or one measured threshold is clearly doing most of the work.

Safest formal next step

Open the matching local project guide first. If the route still looks borderline, move to measured drawings and then to a lawful development certificate, pre-application advice or another formal check as needed.

Official-source check

Where this page shows official sources, use those links near the relevant answer to confirm the latest council or national wording before relying on a borderline route.

Updated May 2026
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