Prior approval: larger single-storey rear extension

The documents, and what each must show

Documents that are always needed come first. Each point is what the check looks for, with the article or guidance it rests on. The council’s local validation list can add to these.

1. Written description

   Always needed

   A written description of the extension with the three key measurements. On the Planning Portal this is the prior approval form; save or download the PDF and upload it here.

   What it must show

   • The file opens and can be read: not password-protected, not corrupted, and text and dimensions are legible when zoomed in.
   • States how far the extension goes beyond the rear wall of the original house.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(a)(i)
   • States the maximum height of the extension.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(a)(ii)
   • States the eaves height of the extension.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(a)(iii)
   • If it joins an existing extension, gives the three measurements for the total enlargement.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(a)(iv)
   • Lists the addresses of all adjoining properties.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(c)
   • Gives your contact address (and email if you want to be contacted by email).GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(d)

   Required by GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(a)

2. Plan of the site and extension

   Always needed

   A plan showing the property, the proposed extension and any existing extension it joins.

   What it must show

   • The file opens and can be read: not password-protected, not corrupted, and text and dimensions are legible when zoomed in.
   • Shows the property boundaries and the house.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(b)
   • Shows the proposed extension, with its depth from the original rear wall dimensioned.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(b)
   • Shows any existing extension the new one joins.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(b)
   • Is drawn to a stated scale (for example 1:200 or 1:500) and shows north.DMPO 2015 art. 7(2) (by analogy); council practice
   • Shows the adjoining houses and the distance from the extension to the boundaries.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(9)(b)

   Required by GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(2)(b)

3. Location plan

   Recommended

   Not required by the GPDO itself, but many councils ask for one, and it makes the site unmistakable. Buy an Ordnance Survey based plan at 1:1250 with the site edged in red.

   Draw the red line around the whole property, including the garden and the drive up to the road. Edge any other land you own nearby in blue.

   What it must show

   • The file opens and can be read: not password-protected, not corrupted, and text and dimensions are legible when zoomed in.
   • The plan is based on an up-to-date map (normally an Ordnance Survey base bought from an accredited supplier), showing today's buildings and roads - including any recent extensions and new houses nearby.PPG Making an application, para. 024 (ID 14-024-20140306)
   • A recognised metric scale is stated, normally 1:1250 or 1:2500, together with the paper size it was drawn for (A4 or A3).PPG Making an application, para. 024 (ID 14-024-20140306)
   • A north point is shown.DMPO 2015 art. 7(2)
   • The whole site is edged clearly in red: for a house, the full property including front and back garden, not just the footprint of the works.PPG Making an application, para. 024 (ID 14-024-20140306)
   • The red line takes in all land needed for the works, including the connection to a public road (it normally reaches the edge of the road or pavement).PPG Making an application, para. 024 (ID 14-024-20140306)
   • Any other land you own next to or close to the site is edged in blue (only if you own any).PPG Making an application, para. 024 (ID 14-024-20140306)
   • Enough surrounding roads and buildings are shown, with at least two roads named, for the site to be found without doubt.PPG Making an application, para. 024 (ID 14-024-20140306)
   • A scale bar is shown, so the plan can still be measured if it is printed at a different size.PPG Making an application, para. 023 (ID 14-023-20140306)
   • The Ordnance Survey copyright and licence number are shown (a sign the map base was bought legitimately and is current).
   • It is a proper location plan, not a screenshot from an online map or satellite image with no scale.DMPO 2015 art. 7(2)
   Common mistakes

   • The red line only goes round the extension, not the whole property.
   • The red line stops short of the road, so the access isn't included.
   • A screenshot from an online map: no scale, no north point.
   • An old map that doesn't show recent extensions or new houses next door.

   Required by GPDO 2015 Sch. 2 Pt 1 para. A.4(8)

4. Proposed elevations

   Recommended

   Drawings of each side of the building as it will look after the works, with heights and materials. Not required by the GPDO itself, but councils use them to judge the effect on neighbours, and may ask for them.

   What it must show

   • The file opens and can be read: not password-protected, not corrupted, and text and dimensions are legible when zoomed in.
   • Drawn to a stated metric scale, normally 1:50 or 1:100, and the paper size is given (or a scale bar is shown).DMPO 2015 art. 7(2); council local validation lists
   • Clearly titled 'proposed', with each elevation labelled (front, rear, side, or by compass direction).DMPO 2015 art. 7(1)(c)(ii)
   • Every elevation that changes is drawn, including the side facing a neighbour.DMPO 2015 art. 7(1)(c)(ii)
   • The new part is drawn together with the existing building, so its height can be compared with the existing roof and eaves.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.1(c)
   • Heights are dimensioned from ground level: ridge or top of the roof, and eaves (or parapet for a flat roof).GPDO 2015 Sch. 2 Pt 1 Class A, para. A.1(d)
   • External materials are written on the drawing (walls, roof, windows, doors), or a materials schedule is referred to.DMPO 2015 art. 7(1)(c)(ii)
   • New windows, doors and rooflights are shown, with side-facing upper-floor windows marked as obscure-glazed where that's proposed.GPDO 2015 Sch. 2 Pt 1 Class A, para. A.3(b)
   • The elevations match the floor plans and the block plan.DMPO 2015 art. 7(1)(c)(ii)
   Common mistakes

   • The side elevation facing the neighbour is missing.
   • No heights, or heights not measured from ground level.
   • Materials not stated.

   Required by GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(8)

5. Proposed floor plans

   Recommended

   Drawings of each floor as it will be after the works, with the new part clearly shown. Not required by the GPDO itself, but councils use them to judge the effect on neighbours, and may ask for them.

   What it must show

   • The file opens and can be read: not password-protected, not corrupted, and text and dimensions are legible when zoomed in.
   • Drawn to a stated metric scale, normally 1:50 or 1:100, and the paper size is given (or a scale bar is shown).DMPO 2015 art. 7(2); council local validation lists
   • Clearly titled 'proposed'.DMPO 2015 art. 7(1)(c)(ii)
   • Every floor the works affect is shown (for a loft conversion, the new loft floor and the floor below with the new staircase).DMPO 2015 art. 7(1)(c)(ii)
   • Room uses are labelled.DMPO 2015 art. 7(1)(c)(ii)
   • The overall external size of the new part is dimensioned (depth and width).DMPO 2015 art. 7(1)(c)(ii)
   • New work is told apart from what is there now (shaded, hatched or annotated).DMPO 2015 art. 7(1)(c)(ii)
   • The plans match the elevations and the block plan: same depth, same openings, same position.DMPO 2015 art. 7(1)(c)(ii)

   Required by GPDO 2015 Sch. 2 Pt 1 Class A, para. A.4(8)