It identifies options and risks; pre-application advice and early design work do not amount to a formal planning decision. [1]
Check the property before choosing a scheme
Begin with the address, existing use, measured information, planning history and known constraints. Council mapping can identify matters such as conservation areas, listed buildings, protected trees and flood risk. Epping Forest District Council also warns that its online application records may be incomplete. [2]
For your feasibility file, ask the adviser to separate confirmed facts from assumptions. Useful headings are: “evidence seen”, “further information needed”, “design implication” and “who will resolve it”. An unanswered question should remain visible in the option comparison.
Establish the approval route
The planning check should distinguish work needing an application from work potentially authorised by permitted development. Those rights depend on the development type and can be restricted by planning conditions or Article 4 directions. Do not transfer an allowance from another house to yours without checking. [3]
National policy is now the NPPF published on 17 August 2026. Avoid relying on obsolete paragraph references from an earlier edition. The draft new London Plan is also under consultation, but a consultation draft is not an adopted replacement plan. [4] [5]
Test the structure and servicing
Ask whether the design needs an engineer's early input, trial pits or other investigations. The Institution of Structural Engineers identifies ground conditions, existing foundations and drainage coordination as potential issues in domestic projects. [6]
Where Thames Water is the sewerage undertaker, check nearby public sewers before fixing the footprint. Its guidance identifies building within 3 metres of a public sewer or 1 metre of a public lateral drain as requiring a build-over assessment/application. [7]
Check ecology without applying old exemptions
Householder applications remain exempt from mandatory Biodiversity Net Gain. From 6 August 2026, a separate exemption covers sites whose area within the application's red-line boundary is 0.2 hectares or less. It does not cover development that decreases the biodiversity value of on-site priority habitat. The self-build exemption was removed for new applications from that date, subject to transitional provisions; another exemption may still apply. [8]
This makes the application date, site boundary and habitat position important for a small new-home proposal. Do not describe every self-build or every small site as automatically exempt.
What should you have at the end?
Request a proportionate written outcome: the options considered, recommended route, major constraints, outstanding investigations and the next decision you need to make. Ask for a budget with clearly labelled exclusions, not a single apparently precise number unsupported by a defined design.
A useful feasibility result can be “proceed”, “revise the brief” or “investigate this issue first”. It need not be a commitment to the largest scheme that fits on a drawing.