What Does Hertsmere Require for a Householder Application?

A local validation list is a council's own list of documents it needs on top of the national requirements, adopted so it can refuse to register an application without them. Hertsmere has none on its planning page, so the national rules set the floor. That sounds simpler than its neighbours, and on paper it is. In practice it moves the judgement from a checklist to you and the case officer.

What do the national requirements actually demand?

The national minimum is short. You need the form, the ownership certificate (A, B, C or D, with notice served on any other owner), the fee, and a location plan showing the site in relation to the surrounding area. Beyond that, the government's guidance says additional plans and drawings will in most cases be needed to describe the proposed development, as required by article 7(1)(c)(ii) of the Development Management Procedure Order 2015 (gov.uk, Making an application).

That last clause is where a householder application is won or lost. The law requires drawings that describe the development; it does not list them. For an extension or loft, the officer can only assess what the drawings show, so a set that leaves out an elevation or the neighbour's window gives the officer a reason to ask, delay or refuse.

What should a Hertsmere householder drawing set include?

Without a council list, we work back from what Hertsmere's design guidance tests. Its Planning and Design Guide Part D (a 2016 draft, used for development management since September 2016) says extensions should not cross a 45-degree line drawn from the nearest habitable-room window next door, kitchens included, and that dormers sit at least 0.3m below the ridge, above the eaves and 0.5m in from the side walls (Hertsmere Design Guide Part D). An officer cannot check either test without seeing it drawn.

So a complete Hertsmere set usually carries:

1. A location plan at 1:1250 or 1:2500 with the site edged red.
2. A block plan showing the extension against the boundaries and the neighbouring houses.
3. Existing and proposed floor plans and elevations at 1:50 or 1:100, every sheet with a scale bar.
4. A roof plan where the roof changes, with dormer set-backs dimensioned.
5. The 45-degree line from the neighbour's nearest habitable-room window, shown on plan or elevation.
6. Parking on the block plan where the work removes a space, since the council's Parking Standards SPD applies to householder extensions (Hertsmere SPDs).

Items 1 and 3 follow the national guidance and the council's own page; items 2, 4, 5 and 6 are our practice for Hertsmere, drawn from what its guidance tests rather than from a validation rule.

What is the Shenley Plan Code Compliance Checklist?

The Shenley Plan Code Compliance Checklist is a form in which the applicant sets out how a proposal meets the Shenley Neighbourhood Plan's design code. Hertsmere asks for it with applications in the Shenley Neighbourhood Plan area and says it will form part of its local validation requirements in due course. The council publishes two versions: one for the applicant to complete at validation and one for the officer's assessment. If your house is in Shenley, the drawings and the checklist need to tell the same story, so we complete the checklist from the finished drawings, not before.

When do Article 4 directions or the Green Belt change things?

In Hertsmere, Article 4 directions and the Green Belt change whether you apply, and what the drawings must show.

Article 4 directions on named Radlett bungalows, in Theobald Street, Williams Way, Faggots Close, Craigweil Avenue, Newberries Avenue, Gills Hill Lane, Goodyers Avenue, Links Drive and The Close, remove rights including adding storeys under Part 1 Class AA (Radlett bungalows Article 4). The council lists further directions in Borehamwood, Bushey, Elstree, Letchmore Heath, Potters Bar, Radlett and Shenley, each removing different rights (Hertsmere Article 4 directions). We have not read every one in full, so we check the direction for your address before design.

Hertsmere has 15 conservation areas, including Elstree Village, Radlett North and South, Shenley, South Mimms, The Royds in Potters Bar and Bushey High Street (Hertsmere conservation areas). In one, expect the officer to want a heritage statement even without a list that says so.

In the Green Belt, the officer compares the extension with the original house on floor space, volume, site coverage and height under Policy SADM26, so the drawings need those figures; our post on extending a house in the Green Belt in Hertsmere explains the test.

Why does pre-application advice matter more in Hertsmere?

Hertsmere says plainly that applications submitted without pre-application discussion that need significant amendments are likely to be refused (Hertsmere pre-application advice). With no local list to tell you what is missing, that warning carries weight. Written householder advice costs £230.40, or £374.40 with a meeting, on the April 2025 schedule the council links (fee schedule). For a modest rear extension that meets the 45-degree line it is often unnecessary; for a two-storey side extension or a Green Belt scheme it can save a refusal.

For example (illustrative, not a real job): a 1950s semi in Borehamwood plans a two-storey side extension. Outside the Green Belt and any conservation area, the national list applies. We would still draw the neighbour's nearest habitable-room window and the 45-degree line, dimension the side gap, show the lost driveway space against the Parking Standards SPD, and export every sheet to PDF with a scale bar. None of that is a Hertsmere validation rule; all of it answers a question the officer would otherwise ask.

How long does Hertsmere take?

Between 1 July 2025 and 30 June 2026, Hertsmere made 208 of its 454 householder decisions under an agreed extension of time; of the other 246, it decided 224 within 8 weeks (MHCLG live table PS2). Since 15 June 2026 the council has been designated under section 62A for its handling of major applications, but it still decides householder applications itself (Hertsmere designation notice).

Some extensions in Hertsmere need no application; run the project through this checker first:

Where one is needed, we charge £895 for the drawings, survey included, and the council's £548 fee is paid to Hertsmere separately. Council detail is on our Hertsmere page and the Hertfordshire page; local costs are in extension plans in Radlett.

Frequently asked questions

Does Hertsmere have a local validation checklist? Not on its planning page. It points to the national validation requirements and adds a few items, including the Shenley checklist in that neighbourhood plan area.

What file format does Hertsmere want? PDF, with plans to a recognised metric scale and a scale bar, according to the council's apply page.

Do I need a CIL form for an extension in Hertsmere? The council asks for the CIL additional information form where necessary. We confirm at the quote stage whether your scheme needs it.

Can I apply by email in Hertsmere? Yes. The council accepts downloaded forms by email to its planning team or by post, with one paper copy.

Is pre-application advice compulsory? No, but the council warns that applications needing significant amendments without it are likely to be refused.