Hanging an exterior door is a physically demanding but straightforward carpentry task if approached methodically. The common failure modes are doors that bind in the frame, gaps that let in draughts, and poorly aligned strikes that either do not latch properly or require slamming. All of these are avoidable with accurate measurement, careful hinge positioning, and patient adjustment. This guide also covers the Building Regulations requirements that apply when you replace an exterior door, obligations that catch many homeowners by surprise.

Tools Needed

  • Tape measure and combination square
  • Pencil and marking gauge
  • Hand plane (jack plane for straightening, block plane for final fitting) or power plane
  • Chisel set (25 mm for hinge morticing)
  • Mallet
  • Drill/driver with drill bits and driver bits
  • Hinge template (jig), strongly recommended
  • Packers and shims (hardwood or composite)
  • Spirit level (1.2 m)
  • Screwdrivers
  • Handsaw or jigsaw (for trimming door bottom)
  • Weatherstripping and threshold bar
  • Silicone sealant and gun

Understanding UK Exterior Door Sizes

UK door sizes are standardised but the range is relatively limited. The most common exterior door leaf sizes are listed below, and 1981×838 mm is generally taken as the most common of all.1

WidthHeightCommon Context
762 mm (2’6”)1981 mm (6’6”)Standard pre-1970s housing
813 mm (2’8”)2032 mm (6’8”)Some older properties, garages
838 mm (2’9”)1981 mm (6’6”)Standard modern housing (most common)
914 mm (3’0”)1981 mm (6’6”)Wider access, some period properties

Always measure the existing opening (the clear structural opening in the masonry or timber frame) before ordering a door. The frame rebate needs to be only a few millimetres larger than the leaf (see the clearances in Step 2), while the structural opening must also allow for the frame section, packers and plaster returns, so check the manufacturer’s stated structural opening size before ordering. If replacing like-for-like in an existing frame, measure the old door leaf directly.

Measure height and width in at least three places: top, middle and bottom (for width) and left, centre and right (for height). Frames are rarely perfectly parallel, and the narrowest measurement governs.

Door Material Comparison

MaterialCost Range (supply only)U-ValueMaintenanceLifespan
uPVC£300–£7001.2–1.6 W/m²KVery low20–30 years
Composite (GRP skin, foam core)£700–£1,8000.9–1.4 W/m²KLow30–35 years
Timber hardwood (oak, meranti)£600–£2,0001.4–2.0 W/m²K (solid); 1.0–1.4 W/m²K (engineered)Medium–high30–50+ years with maintenance
Aluminium£1,000–£3,0001.0–1.4 W/m²K (thermally broken)Low30–40 years

Composite doors dominate new installations in the UK due to their low maintenance, good thermal performance and wide range of styles. Timber doors remain popular in conservation areas and period properties. A listed building needs listed building consent for significant works, and where the council has made an Article 4 direction, changing a front door can need planning permission.2 Always check with your local planning authority before changing door material in a conservation area or on a listed building.

Building Regulations: What You Must Know

Part L: Thermal Performance

Approved Document L, Volume 1: Dwellings (2021 edition) requires that replacement windows and doors in existing dwellings achieve minimum thermal performance. Table 4.2 sets the limits for a new or replacement door as follows.3

  • Doors with more than 60% of the internal face glazed: whole-doorset U-value of 1.4 W/m²K or better, or a Doorset Energy Rating of Band C or better
  • All other doors: whole-doorset U-value of 1.4 W/m²K or better, or a Doorset Energy Rating of Band B or better
  • The figures are for the complete doorset (leaf and frame), not the centre pane. A 1.2 W/m²K centre-pane figure applies only as a fallback where a fully glazed door cannot meet the whole-doorset limit because the building’s character must be maintained (paragraph 4.10), and an external fire doorset may be 1.8 W/m²K (Table 4.2, note 14)3

Most compliant composite and uPVC doors from mainstream UK suppliers already meet this threshold. Fitted by an installer registered with a competent person scheme (FENSA or CERTASS, for example), the door comes with a certificate once the work is complete.4 If you fit the door yourself, or use an unregistered installer, you need approval from a building control body, either the local authority or a registered building control approver, which will check the work.4 A registered installer, by contrast, can self-certify without involving local authority building control.4

Timber solid doors, particularly older ledged-and-braced designs, often do not achieve 1.4 W/m²K without a thermal core or heavy weatherstripping. For a listed building, or a home in a conservation area, Approved Document L does not require full compliance where it would unacceptably alter the character or appearance, so agree the door specification with building control first.3

Document Q: Security

Approved Document Q (Security, 2015) applies to new dwellings, including those formed by a material change of use, not to like-for-like replacements in existing homes.5 It requires easily accessible doorsets, including the entrance door, to be secure doorsets made to a design shown by test to meet PAS 24:2012, or bespoke timber doorsets built to its Appendix B.5 Doorsets meeting other standards of similar or better performance are also accepted, and many suppliers now certify to the current edition, PAS 24:2022.5

If your project is a new build, a barn conversion, or a change of use that requires a full building regulations application, the entrance door must be a secure doorset under Document Q, which in practice means a door certified to PAS 24 or an equivalent standard. Many composite door manufacturers supply doors certified to PAS 24:2022; look for the certificate on the product specification, not just in the marketing copy.6

For ordinary like-for-like replacements in existing homes, Document Q does not apply, but fitting a BS 3621-certified lock and Secured by Design hardware is still best practice and may be required by your home insurer.

Step-by-Step: Hanging an Exterior Door

Step 1, Prepare the frame. Check the existing frame is square, plumb and in sound condition. Rot in the frame must be cut out and repaired before hanging a new door. Use a spirit level to check all four sides. Note any out-of-plumb or out-of-square, you will plane the door to match the frame rather than assume the frame is true.

Step 2, Size the door leaf. A correctly fitting door should have a gap (known as the ‘stile clearance’ or ‘hanging gap’) of approximately 2–3 mm on the hinge side, 2–3 mm on the latch side, and 2 mm at the head. The threshold gap depends on the floor finish and any threshold bar fitted, typically 5–10 mm. Transfer the frame measurements to the door and mark the lines to be planed or sawn.

Step 3, Plane to size. If trimming more than 5 mm from the width, use a circular saw or jigsaw first, then finish with a plane. Always plane from the face to the back to avoid splitting the face veneer. For the top and bottom, plane inwards from each corner to avoid breaking out the face.

Step 4, Mark hinge positions. For exterior doors, use three 100 mm (4-inch) hinges: two are generally inadequate for the weight and wind-loading of an exterior door. Typical hinge positions are about 150 mm from the top of the door, 250 mm from the bottom, and one centred between them. A hinge jig ensures consistent positioning between door and frame; it is the most reliable way to avoid misaligned hinges.

Step 5, Mortice the hinges. Use the hinge as a template, scoring around it with a Stanley knife. Chop out the mortice with a chisel to the depth of the hinge leaf, no more. A hinge leaf recessed too deeply causes the door to bind; one not recessed enough leaves a gap at the frame. The hinge should sit exactly flush with the surface.

Step 6, Fit hinges to the door. Fix the hinge leaves to the door with the screws supplied. For timber doors, pilot holes prevent splitting. Use all screws, short-hinging a heavy door by using only two screws per hinge is a common cause of hinge failure.

Step 7, Hang the door. With a helper or door horses, lift the door into the frame and pack it at the correct height with shims under the bottom edge. Align the door hinges with the frame mortices and fix the frame side of the hinges. Open and close the door, check the gaps on all sides and that the door swings freely without binding.

Step 8, Adjust and plane as needed. Doors rarely fit perfectly on first hanging. Tight spots will leave witness marks on the frame, plane those areas carefully. If the latch side does not close flush, the hinges may be over-morticed (causing the door to spring away from the latch side); pack out the hinge mortice with thin card.

Step 9, Fit the lock. Mark the lock body position on the door edge and chisel out the mortice to accept the lock case. Mark the spindle, keyhole and bolt positions on the face and drill through. Fit the latch/lock body and mark the frame for the strike plate. Mortice the frame for the strike box and fit the strike plate. Test the latch and deadbolt engagements, both should feel positive without requiring force.

Step 10, Weatherstripping. Compression seals should be fitted to the head, hinge side and latch side of the frame before the door is finally closed up. The seal should compress evenly when the door is shut. For the threshold, fit an appropriate threshold bar or draught excluder. The type depends on the floor level relationship between inside and out, and whether a low-threshold (wheelchair-accessible) detail is required. At the principal entrance of a new dwelling, Approved Document M asks for an accessible threshold: level, or with a total upstand of no more than 15 mm.7

Step 11, External sealing. Apply a bead of low-modulus silicone sealant between the frame and the external masonry reveal, and between the frame and the internal plaster. This prevents water ingress at the frame perimeter, a common cause of frame rot that is not visible until significant damage has occurred.

Common Mistakes

  • Hanging with two hinges. Three 100 mm hinges are the usual minimum for a full-size exterior door. With only two, a heavy door is far more likely to sag and strain the frame.
  • Not pilot-drilling timber. Driving hinge screws without pilot holes into hardwood stiles risks splitting the door. In softwood frames, over-driving screws strips the thread; countersink properly.
  • Ignoring the threshold. A well-hung door with a leaking threshold will still produce draughts and water ingress. The threshold detail deserves as much attention as the hanging.
  • Not notifying building control. An external door is a controlled fitting under the Building Regulations, so replacing one needs either a Competent Person certificate or building control approval.4 Many homeowners are unaware of this and only discover it during conveyancing.
  • Mismatching door and frame hand. Confirm the handing (which side the hinges are on, viewed from outside) before ordering. Reversing a door costs time and sometimes money if the door is pre-bored for hardware on the wrong side.

Pro Tips

  • A router hinge jig is worth having if you hang doors regularly: a compact jig costs about £47, and a full two-piece door-and-frame jig about £209.89 It removes guesswork from the most precision-critical stage of the process.
  • For composite doors with multipoint locking, the lock adjustment screws on the gearbox are the primary fine-tuning tool for door alignment, use them before reaching for the plane.
  • In exposed locations, apply end-grain sealer to any timber door at the top and bottom edges, even if the door is pre-primed. End grain absorbs moisture fastest and is the most common starting point for rot.

The rules in this note are those that apply in England. Scotland, Wales and Northern Ireland have their own building standards and permitted development rights.

References (9)

Figures in this note were checked against the sources below on 2 October 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalsupplier figureVivid Doors, guidance.RN-L4ZZA2A UK door supplier's sizing guide listing the standard external door leaf sizes (1981 x 762, 1981 x 838, 2032 x 813 and larger) and naming 1981 x 838 mm as the most common. Supplier source used only for a product-size fact; no official body publishes a door size list.
  2. 2technicalvery strongPlanning Portal, guidance.RN-LIPHMWThe Planning Portal on planning permission for doors and windows: usually not needed for repairs, maintenance and minor improvements including replacing windows like for like, with the exceptions that catch people, listed buildings, conservation areas, flats, and where permitted development rights have been removed.
  3. 3technicalvery strongMinistry of Housing, Communities and Local Government.RN-L0FCJXThe in-force U-value tables a DIY insulation or door note must quote, with the exact numbers. Table 4.2, limiting U-values for new fabric elements in existing dwellings, sets roof 0.15, wall 0.18, floor 0.18, swimming pool basin 0.25, window 1.4 or Window Energy Rating Band B minimum, rooflight 2.2, doors with more than 60 per cent of the internal face glazed 1.4 or Doorset Energy Rating Band C minimum, and other doors 1.4 or Doorset Energy Rating Band B minimum. Table 4.3, for existing elements, gives a roof threshold of 0.35 and an improved value of 0.16, which is the figure a loft insulation note needs: paragraph 4.12 says a retained element whose U-value is higher than the column (a) threshold, for example through a loft or garage conversion, should be upgraded to the column (b) value. Paragraph 4.13 allows a lesser upgrade only where the improved value is not technically or functionally feasible or would not achieve a simple payback of 15 years or less. Paragraph 4.8 requires a replacement element to be no worse than the one it replaces as well as meeting Table 4.2. Paragraph 4.10 gives the heritage exception: where character must be maintained, a centre pane U-value of no more than 1.2 or low-emissivity secondary glazing. Note 9 records that the timber window concession of 1.6 or Band C ended on 14 June 2023. The 2021 edition came into force on 15 June 2022; a 2026 edition exists at https://assets.publishing.service.gov.uk/media/69c122a6cfa346b9d4704a55/ADL1_2026.pdf.
  4. 4technicalvery strongPlanning Portal, guidance.RN-33F8DPThe Planning Portal on building regulations for doors and windows: since 1 April 2002 the regulations have applied to all replacement glazing, covering thermal performance, safety glazing, means of escape and ventilation. That 2002 date is the one that matters at sale, because it is when a FENSA certificate or a building regulations notice started being expected for replacement windows.
  5. 5technicalvery strongMinistry of Housing, Communities and Local Government.RN-VGR6O6The security standard for doors and windows, ISBN 978 1 85946 601 8, in force from 5 March 2015 and last updated 22 November 2024. Requirement Q1 applies only to new dwellings, and to easily accessible doors and windows giving access into a dwelling from outside, into a building containing flats from outside, or into a flat from the common parts. Paragraph 1.2 requires secure doorsets tested to PAS 24:2012 or designed to Appendix B, with STS 201 Issue 5:2013, LPS 1175 Issue 7:2010 security rating 2, STS 202 Issue 3:2011 burglary rating 2 and LPS 2081 Issue 1:2015 security rating B accepted as equivalents. Paragraph 1.3 caps a letter plate aperture at 260mm x 40mm and points to DHF technical specification TS 008:2012. Paragraph 1.4 requires a door viewer on the main entrance door unless clear glass or an adjacent window serves the purpose, plus a door chain or limiter. Paragraph 2.2 requires ground floor, basement and other easily accessible windows and rooflights to be tested to PAS 24:2012, with STS 204 Issue 3:2012, LPS 1175 rating 1 and LPS 2081 rating A as equivalents, and paragraph 2.3 requires frames to be mechanically fixed to the structure. Appendix B specifies a doorset in solid or laminated timber to a minimum density.
  6. 6technicalstrongBSI Knowledge, a standard.RN-LUDU9FThe current version of PAS 24, published 30 September 2024, superseding PAS 24:2022. It specifies test methods and acceptance criteria for doorsets and windows intended to resist the attacks associated with a casual or opportunistic burglar, covering hinged, sliding, pivot and folding windows and single and double leaf hinged, sliding, pivot and folding doorsets. The A1:2024 amendment was made to keep pace with the changing modus operandi of criminals and to update referenced industry documents. It tests the manufactured product before installation and does not specify materials or installation methods. PAS 24 is the specification behind Approved Document Q in England and Wales, appears at clause 4.13 of the Scottish building standards, and certification to it is one route to meeting the police Secured by Design scheme.
  7. 7technicalvery strongMinistry of Housing, Communities and Local Government.RN-5IVIKFParagraph 1645 of the M4(2) guidance requires a minimum 1,200 mm clear space in front of and between all kitchen units and appliances in living, kitchen and eating areas. Wall switches, socket outlets, stopcocks and controls must have their centre line between 450 mm and 1,200 mm above floor level (Diagram 1.5), consumer units are mounted with switches 1,350 to 1,450 mm above floor level, and boiler timer controls and thermostats between 900 mm and 1,200 mm. Communal approach routes and flights need a minimum clear width of 1,200 mm and every landing a minimum 1,200 mm clear of any door swing. Handrail guidance is measured 450 mm above the pitch line of the treads.
  8. 8costsupplier figureScrewfix.RN-0DT5UNA price, true at 2026-09. Screwfix's product page for Trend's two-piece aluminium hinge jig for recessing door and frame hinges, priced at £208.99 including VAT.
  9. 9costsupplier figureToolstation.RN-R4F4YNA price, true at 2026-09. Toolstation's product page for a compact Unika router hinge jig for 76 mm and 102 mm hinges in doors and frames, priced at £46.99 including VAT.

  1. External Door Sizes, Vivid Doors, accessed 30 September 2026. vividdoors.co.uk

  2. Doors and windows: Planning permission, Planning Portal, accessed 30 September 2026. planningportal.co.uk

  3. Approved Document L, Conservation of fuel and power, Volume 1: Dwellings, 2021 edition incorporating 2023 amendments, HM Government, accessed 7 September 2026. assets.publishing.service.gov.uk

  4. Doors and windows: Building Regulations, Planning Portal, accessed 30 September 2026. planningportal.co.uk

  5. Approved Document Q: Security, Dwellings, 2015 edition, HM Government, accessed 30 September 2026. assets.publishing.service.gov.uk

  6. PAS 24:2022+A1:2024, Enhanced security performance requirements for doorsets and windows in the UK, BSI, accessed 2 October 2026. knowledge.bsigroup.com

  7. Approved Document M, Volume 1: Dwellings, 2015 edition incorporating 2016 amendments, HM Government, accessed 30 September 2026. assets.publishing.service.gov.uk

  8. Trend H/JIG/A 1250mm 2-Piece Aluminium Hinge Jig, Screwfix, accessed 2 October 2026. Priced at 2026-09 and left there. screwfix.com

  9. Hinge Jig by Unika, Toolstation, accessed 2 October 2026. Priced at 2026-09 and left there. toolstation.com