# Wilwyn, Chelmsford Road, Blackmore

- **Decision:** dismissed, 26 August 2026
- **Decided by:** Planning Inspector: B Pattison
- **Authority:** Brentwood (East of England)
- **Appeal reference:** 6012008
- **Application reference:** 26/00225/HHA
- **Procedure:** householder
- **Development:** Rear extension, loft conversion, internal alterations; replacement garage
- **Site context:** green-belt
- **Green Belt:** yes (grey belt not-argued)
- **Framework applied:** August 2026 NPPF
- **Determinative policies:** GB7(1)(b), GB6(2), P3
- **Development plan policies:** Brentwood Local Plan 2022 MG02, BE14
- **Main issues:** inappropriate development, openness, living conditions, character, VSC
- **Tags:** disproportionate-extension, householder, vsc-not-shown, openness-harm, neighbour-context-irrelevant, transitional-no-consultation

## Summary
Large rear extension and new first floor to a modest dwelling among larger houses. Dismissed. A cumulative increase of 239.4% was disproportionate under GB7(1)(b), with limited openness harm and loss of light to a neighbour. No VSC.

## Issues and findings
- **Transition.** The changes "are not fundamental to matters which are determinative" (DL ¶2).
- **GB7(1)(b): FAIL.** "Wilwyn is currently notably smaller than other nearby properties. However, the Framework requires proposals to be assessed against the size of the original building" (DL ¶8). The garage demolition did not avoid disproportion (DL ¶9).
- **Openness: limited harm**, reflecting the context of large residential properties (DL ¶14).
- **Living conditions:** a marginal 45-degree breach was still harmful (DL ¶19).
- Improved living conditions for the occupiers had only limited weight (DL ¶25).

## Planning balance
GB6(2): the considerations do not clearly outweigh the harm (DL ¶28).

## What made the difference
The size of the cumulative increase (239%). Local context of larger homes is irrelevant to the (b) test.

## Transferable points
- Neighbouring larger houses do not affect the proportionality test, which compares with the original building (DL ¶8).
- Demolishing an outbuilding does not offset a disproportionate enlargement of the dwelling (DL ¶9).

## Policy findings
- **GB7(1)(b): fail.** undisputed cumulative floor area increase of 239.4%; comparison is with the original building, not with larger neighbours (DL 5-10)
- **GB6(2): harm (substantial weight).** limited spatial and visual openness harm in a context of large dwellings (DL 13-15)
- **P3: conflict.** marginal breach of the Essex Design Guide 45-degree plan line; loss of light to a neighbour's habitable room (DL 16-21)

## Key facts
- Cumulative increase over the original of 239.4%; 7.5 m deep rear extension plus a new first floor
- Host dwelling notably smaller than neighbouring two-storey houses
- Removing the detached garage did not offset the increase

## Sources
- https://appeal-planning-decision.service.gov.uk/comment-planning-appeal/appeals/6012008
- https://appeal-planning-decision.service.gov.uk/published-document/897d8a75-6eaa-4049-9f96-ece85e19cb77

---

Source: https://planningdistilled.org/research/england/nppf-navigator/decisions/PINS-6012008.html

A summary of a public planning decision, written from the decision letter. Not legal advice. © Planning Distilled. Released under the Creative Commons Attribution 4.0 licence (https://creativecommons.org/licenses/by/4.0/): share and adapt freely, with credit to Planning Distilled. Quotations from decision letters, plans and the Framework remain the copyright of their publishers.