Drawing conventions that cause validation queries

Most validation queries are not about planning. They are about drawings that are missing a north point, a scale bar, a drawing number or a red line that includes the access. The national information requirements in the Development Management Procedure Order 2015 are short, and the authority's local list fills in the detail, but the conventions that satisfy both are mostly unwritten and learned by having an application returned.

For a practice submitting several applications a month, the cost is not the resubmission. It is the fortnight of dead time between the validation officer's email and the day the application enters the system, repeated across every job.

The scales expected for each drawing

Authorities expect drawings at recognised scales, and the expectations are consistent enough across England to treat as standard.

Two specific traps. A location plan at 1:200 is not a location plan, because it does not show the surrounding context the officer needs. And a drawing issued at A1 and printed at A3 is at half scale, which is why the paper size matters as much as the ratio.

State the intended paper size on every sheet. Then the officer printing it at A3 knows the drawing was set out for A1 and can scale accordingly.

Scale bars, and why a stated scale is not enough

A stated scale is only true at one paper size. A scale bar remains true whatever size the sheet is printed or displayed at, which is why almost every local list asks for one.

Put a graphic scale bar on every drawing, including the floor plans. Make it long enough to be useful, so a bar reading 0 to 10 metres on a site plan rather than 0 to 1 metre.

The related habit is dimensioning. Even with a scale bar, dimension the things the decision turns on: the depth of the extension, the distance to the boundary, the ridge height, the eaves height, the width of the access. An officer who has to scale off a drawing to find the depth of a rear extension will send a query, and a condition tying the development to a dimensioned drawing is much easier to enforce.

North points and orientation

A north point belongs on the location plan, the block plan and the site plan. It is a small thing and it is one of the most common reasons an application is returned.

It matters more than it looks. Daylight, sunlight and overshadowing assessment all depend on orientation, and a case officer forming an initial view of a rear extension needs to know whether the neighbour's garden is to the north or the south. On a sloping site, add spot levels and a direction of fall.

Keep the north point consistent across the drawing set. A location plan oriented with north up and a site plan rotated to suit the sheet is a frequent source of confusion, and if you rotate a plan, say so clearly rather than relying on the arrow alone.

Existing and proposed, side by side or separate

Every application involving alteration needs both the existing and the proposed situation. The disagreement between practices and authorities is whether they go on the same sheet.

The safe approach is to label unambiguously and avoid mixing. Either put existing and proposed on separate numbered sheets, or put them on one sheet with clear headings and a dividing line. What does not work is a single drawing with proposed work shown in a different line weight and no separate existing drawing, because the officer cannot show the existing situation to a committee or to a neighbour.

Three points that generate queries:

• Existing elevations omitted because nothing changes on that face. Submit them anyway.
• Existing floor plans drawn from the proposed layout rather than surveyed, so dimensions do not match the building.
• Demolition not shown. Where part of the building goes, show it hatched on an existing drawing.

For a scheme where design rationale matters, the Design and Access Statement should reference the drawing numbers directly, so the text and the drawings cannot drift apart through revisions.

The red line, the blue line and the fee

The location plan must outline in red all the land necessary to carry out the development. That includes the access, any visibility splay within your control, land needed for drainage, and land needed for construction access where it forms part of the proposal.

Other land owned or controlled by the applicant adjacent to the site is outlined in blue.

Getting the red line wrong causes three separate problems. The application may be invalid because the development cannot be carried out within the area shown. The ownership certificate may be wrong, since the certificate relates to the land within the red line, and ownership certificates A to D depend on who owns that land. And the fee may be wrong, because some fee categories are calculated by site area.

Check the red line last, after the drawings are complete, and ask one question of it: can everything shown on the proposed drawings be built inside this line. Where the answer is no, extend the line and revisit the certificate.

Fee errors are a common cause of invalidity in their own right, and the rules on planning fee exemptions and reductions are worth checking before the submission rather than after an invalidity notice.

Drawing numbers and revision control

Every drawing needs a unique number and a revision reference. The decision notice will list the approved drawings by number and revision, and that list becomes the legal definition of what was permitted.

A workable convention has four parts: a project code, a drawing type code, a sheet number and a revision letter. Whatever system you use, three rules apply.

Never reuse a number for a different drawing. Never issue two drawings with the same number and revision. And change the revision letter whenever anything on the sheet changes, including a note or a dimension.

Keep a drawing issue sheet recording what was submitted and when. When the authority asks, six months later, which version of the proposed elevations was approved, the issue sheet answers it in seconds. Where amendments follow, that record is what makes a later non-material amendment or a discharge of conditions submission straightforward.

Context and street elevations

Local lists frequently ask for a street elevation or a context drawing where the site is in a conservation area, in a terrace, or next to a building of different height.

What is being asked for is a measured elevation showing the proposal between its neighbours, drawn at the same scale and with the neighbouring eaves and ridge lines marked. A photomontage is not a substitute, because it cannot be measured.

Two practical notes. Survey the neighbouring heights rather than estimating them, because the drawing will be used to assess whether the proposal sits comfortably in the street. And include the existing street elevation as well as the proposed, for the same reason you include existing elevations generally.

Where design or heritage context carries the argument, support the drawings with a short Planning Statement that refers to the street elevation by drawing number.

A pre-submission checklist

Run this before every submission and the validation query rate drops sharply:

1. Location plan at 1:1250 or 1:2500, with two named roads, a north point, a scale bar and the site edged red.
2. Blue line shown for other adjacent land in the same ownership or control, or confirmed as not applicable.
3. Block or site plan at 1:500 or 1:200 with boundaries, levels and the access.
4. Existing and proposed floor plans and all elevations, separately numbered.
5. Sections through the site where levels change.
6. Every sheet carrying a drawing number, revision, scale, scale bar and intended paper size.
7. Dimensions on the measurements the decision will turn on.
8. The authority's local validation list read for this application type, not a list from a previous job in a different district.
9. The fee calculated against the current schedule and the red line area.
10. The ownership certificate matching the red line.

That ninth item is the one most often skipped. Local lists differ between neighbouring authorities, and the difference is usually two or three extra documents rather than a different philosophy.

Enter your postcode on PlanScope to see which supporting documents an application is likely to need alongside the drawing set.

This is general guidance, not legal advice; check your authority's current validation list and the position with the local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.