Sutton planning guide: what the August 2026 validation list makes mandatory, and the Local Plan behind it

Sutton's householder rows: mandatory, and mandatory if

The council's planning page links its Local Validation List 2026, whose cover reads “Adopted 24/08/2026”. For a householder application, three forms and fees rows are always mandatory: the application form, the CIL additional information form and the fee. Floor plans, photographs and a 1:1250 site location plan are mandatory every time. The photographs should show all sides of the house, plus front and rear streetscene photos that include the neighbours.

The rest turn on the work. A 1:500 block plan is mandatory if the work goes beyond the current external walls or adds an outbuilding. Elevations are mandatory if any of the work is visible from outside, and must be shown from every side where new elements are visible. Roof plans are mandatory if there is any new roof element, though a first floor plan showing the roof of a ground-floor extension is enough. Sections are mandatory if floor-to-ceiling heights change, as in a loft conversion or dormer, or when land levels differ across the site, and must run through the front and rear garden to show the levels next door. Streetscenes are mandatory when you add a new storey, but not for a loft or dormer. Our rear extension drawings and loft conversion drawings are drawn to this list.

Green Belt: a volume test with a 1948 baseline

Where a house stands in the Green Belt or on Metropolitan Open Land, Policy 24 says the council will grant extensions, alterations and replacement provided “the increase in the external volume of the built form is no greater than 30% above the size of the original building”. The supporting text moved the measure from floor area to external volume, treats the 30% as an indication rather than a guarantee, and says the council will also look at mass, scale and any increase in ridge height.

The “original building” is the building, and any garages and ancillary buildings within 5 metres, that existed in 1948 or when first built if later. Later extensions do not count as original. So the first job on a Green Belt site in Sutton is a volume calculation from a survey, and then the extension drawings. A planning constraints report shows whether your plot is in the Green Belt before anything else is drawn.

Heritage: conservation areas, local character areas and locally listed homes

Sutton's Policy 30 text lists the borough's assets at adoption in 2018: 15 nationally recognised conservation areas, 176 listed buildings, 22 Areas of Special Local Character, “locally designated areas similar to Conversation Areas”, and 106 locally listed buildings. The national Planning Data register lists 15 live conservation areas, matching the plan. Check your address on the council's Local Plan policies map, because the validation list uses that map as its test.

A heritage statement is mandatory if the works are in a conservation area or the property is listed or locally listed. Window sections are mandatory for new windows on a listed or locally listed building, and for replacement windows in a conservation area or on a listed or locally listed building. Our heritage statement page covers the document, and the prior approval larger home extension page covers the larger home extension route.

Fire statement, ecology and crossovers: the rows people miss

The Fire Safety Strategy (Part A) row is marked mandatory on householder applications. You must submit either a Reasonable Exception Statement or a Fire Safety Strategy, which shows where fire and rescue pumping appliances can be sited and the outside evacuation assembly point, plus a statement covering risk-to-life features, fire spread, escape, evacuation and firefighting access. Our fire safety statement page covers it.

An ecological assessment is mandatory if you convert a loft or alter the roof within a Site of Nature Conservation Interest or a Green Corridor, with a preliminary roost assessment by a suitably qualified person. A crossover agreement is mandatory if the application proposes a new or amended vehicular crossover, and the council says a decision can take up to 4 weeks after applying online. A contaminated land assessment is mandatory on contaminated land, and an archaeological desk-based assessment where the site is within 50m of an Ancient Monument and footings are new.

Building control and the party wall

Sutton's building control service takes building notices and full plans applications, books inspections at the mandatory stages and issues completion certificates, and has a page on boundaries, party walls and garden walls. Our building regulations reports guide sorts the drawings, a drawing check, comments answered and regularisation. The Party Wall etc. Act 1996 is national law that runs beside either application, and our party wall services guide explains the notices to neighbours.