Hertsmere Borough Council

Adopted Documents We Assess Against

Development plan: Hertsmere Local Plan 2012-2027

Documents are re-checked against the council's own website weekly. A detected change flags "Policy Update Available" for human review — live assessment standards are never replaced automatically.

Hertsmere Borough Council standards at a glance

1 numeric standards taken from Hertsmere Borough Council's own adopted documents, each shown with the paragraph it comes from. Figures differ between councils — these are this one's.

Rear extension depth

up to 3.35m

Hertsmere will likely refuse a rear extension deeper than 3.35 metres - and on a terrace or a newer house they may think even that is too much. Their 45-degree line is drawn from the near edge of your neighbour's window, not the middle, so it bites sooner than you might expect. Planning and Design Guide Part E paras 1.c, 1.d and 1.l

Standards are what the council normally expects, not a guarantee. A scheme outside them can still be approved on its merits, and one inside them can still be refused for another reason.

Authored Policy Library

4 local policy checks, each citation-locked to the adopted document. National policy (NPPF, national space and daylight standards) applies alongside these.

Hertsmere Site Allocations and Development Management Policies Plan (2016)

• Hertsmere SADM Policy SADM30 and Core Strategy Policy CS22 — Design character Hertsmere will judge your extension against their design principles (SADM30) and their extensions design guide. Subordinate additions in matching materials are the safest starting point.
• Hertsmere SADM Policies Plan (residential amenity policies) — Amenity neighbouring (provisional citation) Hertsmere will look at the effect on your neighbours' light, outlook and privacy. Show the relationship to their windows on your drawings.

Hertsmere Planning and Design Guide Part E: Guidelines for Residential Extensions and Alterations (2006)

• Planning and Design Guide Part E paras 1.c, 1.d and 1.l — Rear extension depth Hertsmere will likely refuse a rear extension deeper than 3.35 metres - and on a terrace or a newer house they may think even that is too much. Their 45-degree line is drawn from the near edge of your neighbour's window, not the middle, so it bites sooner than you might expect.
• Planning and Design Guide Part E para 1.e and EKP-8 — Amenity neighbouring Hertsmere want 60 square metres of garden left for a two or three bedroom house, 80 for a four bedroom and 100 for five or more. Add a bedroom and the garden you have to keep goes up with it.