Brent's policy illustrates how several tests can operate together. [1] [2]
Read the whole conversion policy
A floorspace threshold is not necessarily the only test. Check the policy's definition of a family home, its method of measuring the building and the requirements for the proposed units. Also identify whether its wording concerns the original house, the existing house or a house that can acceptably be extended. Those are not interchangeable descriptions. [1]
Keep the measurement exercise separate from the accommodation schedule. The former answers whether the property qualifies for conversion under the local policy; the latter tests whether each proposed dwelling meets its own space requirements. [1] [3]
Example: Brent's conversion policy
Brent adopted its current Local Plan in 2022. Policy BH11 addresses conversion of family-sized housing containing three or more bedrooms. Its criteria include a home of at least 130m², or one that can acceptably be extended to that size; retention of at least one three-bedroom family dwelling, preferably with direct garden access; and a public transport accessibility level of at least 3. [4] [1]
The policy also contains an exception involving existing accommodation whose amenity deficiencies cannot be remedied and make continued family occupation unlikely. That is an evidence-based exception, not a general invitation to bypass the criteria. [1]
Brent's 130m² wording is not a universal requirement for an unextended original house. Nor should its threshold, transport test or exception be applied to a different borough. [1]
Prepare an evidence sheet for the property
Before choosing a final scheme, assemble:
- The current adopted conversion policy and any relevant supporting guidance.
- Existing plans with a clear area calculation and bedroom arrangement.
- Proposed plans identifying the family accommodation, access and garden allocation.
- A separate space-standard schedule for every resulting flat. [1] [3]
Where an extension is proposed to make the conversion feasible, assess that extension as part of the actual development. Do not assume that extra floor area drawn on a plan will be acceptable merely because it would cross a conversion threshold. [1]
Keeping a family unit means more than retaining a label
Use a layout that demonstrates the proposed occupancy and the rooms needed to support it. A three-bedroom label does not establish compliance where bedroom widths, storage or total area fall short of the applicable standard. London housing-quality policy also addresses matters such as outlook and private outdoor space. [3] [2]
Check the policy version
Use the adopted plan and distinguish it from an emerging replacement. The draft new London Plan remains a proposal, with consultation closing on 15 October 2026. A later policy change should trigger a new assessment rather than retrospective alteration of the policy basis recorded in an earlier application. [5]