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CM1 · Chelmsford · Chelmsford

Planning and building regulation drawings in Chelmsford (CM1)

CM1 is the Chelmsford district, with Writtle and Broomfield among the places it takes in, and it is covered by Chelmsford City Council. For a householder the postcode is only a starting point. What decides the drawings is whether the address sits inside one of the conservation areas that the national planning data register shows overlapping CM1: Chelmsford Central, Chelmsford West End, Good Easter, High Easter, Roxwell, Springfield Green or Writtle. Not all of those carry the city's name, so a house with a Chelmsford postal address can be in a very different planning position from another in the same district.

MCIAT chartered technologists
Chelmsford City Council granted 90% of 777 householder applications
Drawings in about 7 days

Inside a conservation area, the rules for a rear extension, a side extension or a roof alteration change. Side extensions and roof enlargements stop being permitted development, and a rear extension of more than one storey does too. Cladding any part of the outside of a house with stone, artificial stone, pebble dash, render, timber, plastic or tiles is also taken out of permitted development. In practice, an extension that might have needed no application elsewhere becomes a full householder application, and the drawings carry more of the argument. They need to show the existing house, the proposed work, the materials and how the new volume meets the old.

Outside the designated areas, permitted development still has limits on depth, height and how close work can come to a boundary, and each one has to be checked against the actual plot. Our drawings are prepared by chartered architectural technologists, and our fixed fees are set out on the pricing page; we confirm the fee for a Chelmsford address when we quote. We check your address against the designations before anything is drawn.

Planning in Chelmsford: what to know before you apply

Chelmsford City Council is a district-level planning authority, so a householder application goes to it directly. A valid application brings together the application form, a location plan, a block plan, existing and proposed floor plans and elevations, the correct ownership certificate or notice and the fee. Where the house sits in a conservation area such as Writtle or Chelmsford West End, the drawings should make the materials clear, and the council's local validation list may ask for a short statement on how the proposal affects the character of the area. The application is publicised to neighbours, and a parish or town council that has asked to be told about applications is notified. A householder decision can be made by an officer under delegated powers or by a committee. Building regulations approval is a separate process with its own set of drawings.

Applications are decided by Chelmsford City Council — its planning pages.

Check your route

Does your Chelmsford project need planning permission?

Route check · Chelmsford (CM1)

ProjectProperty

Listed building?

Conservation area?

Likely permitted development — no planning applicationNeeds checking

A single-storey rear extension up to 4 m deep on a detached house, or 3 m on any other house, is Class A permitted development subject to the height and materials conditions.
This council does not publish its Article 4 directions to the national register, so the schedule is confirmed with the council first.
Where permitted development applies, a lawful development certificate proves it for lenders and buyers.

Sources: GPDO 2015, Schedule 2, Part 1 · Planning Portal — common projects · Building Regulations 2010 — when approval is needed

This is a first-pass indication from the national rules, not planning advice for your property. Your council's registers, any Article 4 schedule and the exact dimensions decide it — the free appraisal checks all three before we recommend a route.

Confirm it with a free appraisal

Chelmsford (CM1) in numbers

What Chelmsford City Council has decided, and what CM1 is built of — the two facts that shape every job here.

Householder planning decisions — Chelmsford City Council

Chelmsford (CM1) applications are decided by Chelmsford City Council; these are its published householder figures for the last four quarters.

Householder applications decided2025 Q2 to 2026 Q1	777
Granted	700
Refused	77
Grantedof 777 decisions · England 90%	90%
Decided within 8 weeksof 701, excluding prior approvals	93%

Source: Ministry of Housing, Communities and Local Government (PS2 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Permitted development prior approvals — Chelmsford City Council

How the larger-home-extension route has fared with Chelmsford City Council, which decides CM1 notifications.

Larger home extension prior approvals — not required2024 Q2 to 2026 Q1	60
Prior approval granted	4
Prior approval refused	2

Source: Ministry of Housing, Communities and Local Government (PS1 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Planning appeals — Chelmsford City Council

Refusals in CM1 can be appealed to the Planning Inspectorate; this is Chelmsford City Council's householder appeal record.

Householder appeals determined2021–2026	115
Allowed	28
Allowedof 115 · England 36%	24%

Source: Planning Inspectorate appeals casework. Open Government Licence v3.0 Extracted 2026-09-22.

Conservation areas and Article 4 directions — Chelmsford City Council

Register counts for Chelmsford City Council, and the designations whose polygons hold CM1's own postcodes. A count describes what the council has published, never a rank against another council.

Conservation areas in the register25 dated, 1969–2017	25
Article 4 directions in the register	29
Areas covered by an Article 4 direction	26
Conservation areas in the register, within CM1Chelmsford Central, Chelmsford West End, Good Easter	7

Source: MHCLG Planning Data Platform. Open Government Licence v3.0 Extracted 2026-09-22. Source: MHCLG planning.data.gov.uk; Ordnance Survey Code-Point Open. Contains OS data © Crown copyright and database right 2026; Contains Royal Mail data © Royal Mail copyright and database right 2026; Contains National Statistics data © Crown copyright and database right 2026. Open Government Licence v3.0 Extracted 2026-09-22.

Day 0Measured survey of your Chelmsford property — or your existing plans if you have them.
About 7 daysDrawings issued for your approval. Free redraws until you are happy.
SubmissionWe validate against Chelmsford City Council’s checklist and submit on your behalf.
Council: 8-week targetHouseholder applications carry an 8-week statutory target. Chelmsford City Council decided 93% of 701 recent householder applications inside it.

Source: Ministry of Housing, Communities and Local Government (PS2 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Nearby

Chelmsford (CM1) — FAQs

I live in Writtle. Do I need planning permission for a single-storey rear extension?+

It depends on the designation. If your house falls inside the Writtle conservation area, a single-storey rear extension can still be permitted development, subject to the usual limits, but a side extension or a roof enlargement cannot. If it falls outside, more of the work may be permitted development. Check the address against the council's map first, then confirm the limits against the actual plot. An optional lawful development certificate is a way to have the council confirm the position in writing.

Does Broomfield being in CM1 mean the same rules apply as in Chelmsford Central?+

Not automatically. The conservation areas the register shows in CM1 are listed by name, and Broomfield is not one of them. A house there is judged against the ordinary permitted development rules and the council's usual householder considerations unless a designation applies to the particular address. A house in Chelmsford Central is in a different position, and the drawings should reflect that.

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