Balustrade and handrail rules in England

At a glance

Millimetres, 2013 edition (England). "Dwelling" means the diagram's "single family dwellings".

Scope: England, the 2013 edition

Approved Document K is practical guidance on how to meet Part K of the Building Regulations 2010. It is guidance, not the regulations themselves: the document says there is no obligation to follow its solutions, and that if you prefer another way to meet a requirement you should discuss it with building control. This sheet covers the parts that decide how high a balustrade or handrail must be, how large a gap it may leave, and when glass needs special care.

The edition read is the 2013 edition, for use in England, which took effect on 6 April 2013 and is the edition gov.uk lists today. Two matters sit outside it: fire performance of balcony materials is dealt with in Approved Document B, and the design of accessible routes in Approved Document M. Neither is covered here.

Guarding heights (Diagram 3.1)

Guarding must be at least the height shown in Diagram 3.1 for the building type and location (para 3.2a). A wall, parapet, balustrade or similar obstruction can serve as guarding (para 3.2b). Guarding is needed wherever it is reasonably necessary for safety at the edge of a floor, gallery, balcony, roof, stair or sunken area next to a building (para 3.1). The Performance statement under requirement K2 puts the threshold at a fall of more than 600 mm in a dwelling, and at more than two risers (or 380 mm if not part of a stair) in other buildings.

• A Juliet balcony is listed with external balconies at 1,100 mm for single-family dwellings (Diagram 3.1).
• Stairs: guard the sides of flights and landings where the drop in a dwelling is more than 600 mm (para 1.41), and in other buildings, and the common parts of buildings containing flats, where there are two or more risers (para 1.40). Paragraph 1.38 sends you to Diagram 3.1 for the height.
• Opening windows: Diagram 3.1 gives 800 mm for guarding at opening windows, except roof windows in loft extensions (see Approved Document B1). Where a person may fall through a window above ground floor level, para 8.2 asks for opening limiters or guarding.
• The handrail can be the top of the guarding if you can match the heights (para 1.34b).

The 100 mm sphere rule, and when it applies

The document ties the rule to a condition. In a building that may be used by children under five years of age during normal use, guarding should (a) have no opening that a 100 mm sphere can pass through, so a child cannot be held fast, and (b) avoid horizontal rails, so a child cannot readily climb it (para 3.3). The same two points are made for guarding to a flight of stairs in para 1.39. The reading is plain: where the condition applies, both parts apply.

The document does not list which building types may be used by children under five, so do not assume the rule falls away for a given project. Settle it with building control at design stage. Horizontal bar or cable infill is a popular metalwork pattern, and para 3.3b asks you to avoid horizontal rails where the condition applies, so agree the infill with building control before it is drawn.

The test is for any opening in the guarding, so check each gap on the drawing, including the gaps at posts and at the foot of the infill. A stair in a dwelling with open risers has its own 100 mm sphere test (para 1.9b); the stair sheet in this library covers it.

Handrail heights (para 1.34 and Diagrams 1.11 to 1.13)

• All buildings (para 1.34): the top of the handrail is 900 to 1,000 mm from the pitch line or floor, and a handrail goes on both sides if the stair is 1,000 mm wide or more.
• Common stairs in blocks of flats without a passenger lift, and buildings other than dwellings (para 1.35): continuous handrails on each side of flights and landings. Diagram 1.11 (flats) shows 900 mm above the pitch line and 1,000 mm at landings; Diagram 1.12 (other buildings) shows 900 to 1,000 mm above the pitch line and 900 to 1,100 mm at landings. Both show a minimum 300 mm extension at the ends.
• Buildings other than dwellings (para 1.36): where there is full-height structural guarding and a second, lower handrail is provided, its top is 600 mm vertically from the pitch line; a continuous handrail along flights and landings; no projection into the access route; a handrail that contrasts visually with its background without being highly reflective; a slip-resistant surface that, in places with extreme temperatures, does not become excessively cold or hot to touch; an end finished so clothing is not caught; and the profile in Diagram 1.13 (circular 32 to 50 mm diameter, or non-circular 50 mm wide and 39 mm deep with rounded edges).
• Metal handrails: para 1.36e notes that where resistance to vandalism or low maintenance matters, metals with relatively low thermal conductivity may be appropriate, and para 1.36d is a reminder for polished finishes: the handrail should not be highly reflective.
• Dwellings on severely sloping plots (para 1.37): in the entrance storey, a flight of three or more risers needs a continuous handrail on each side and on intermediate landings.

Paragraph 1.34a gives one range for all buildings while Diagrams 1.11 and 1.12 show landing heights up to 1,000 or 1,100 mm. Read the paragraph and the diagram for your building type together, and where they seem to differ, ask building control which governs.

Glass in balustrades and glazing in critical locations (Section 5)

Where glazing is used in guarding, para 3.2d sends you to Section 5. Section 5 shows critical locations in Diagram 5.1 (paragraph 5.1): the shaded areas in doors, side panels, walls and windows to which requirement K4, protection against impact with glazing, applies. In a critical location, glazing must do one of the following (para 5.2):

• Break safely (paras 5.3 and 5.4): suitable if it meets Class 3 of BS EN 12600 or Class C of BS 6206, or, in a door or door side panel with a pane wider than 900 mm, Class 2 of BS EN 12600 or Class B of BS 6206.
• Be robust (para 5.5) or in small panes (paras 5.6 and 5.7). Diagram 5.3 gives the maximum dimensions and a maximum area of 0.5 m² for a small pane, and para 5.7 sets a minimum thickness for annealed glass.
• Be permanently protected by a screen (para 5.8) that keeps a 75 mm sphere from touching the glass, is robust and, if the glass is there to stop falls, is difficult to climb (for example no horizontal rails).

The document does not give glass thickness or build-up for a glass balustrade that must itself resist the loads in para 3.2c. That is for the structural engineer and the glazing supplier.

Loads and fixings: for a structural engineer

Paragraph 3.2c says guarding should resist, as a minimum, the loads given in BS EN 1991-1-1 with its UK National Annex, and PD 6688-1-1, and the note to para 3.2 refers to BS 6180 for further guidance on barriers and infill panels. This sheet states no load figure: those standards were not read for it. Which category of load applies depends on how the area is used, and the structural engineer chooses it, checks the posts and fixings, and checks the structure they are fixed to.

The partner workshop that fabricates the balustrade should supply calculations or test evidence for its system, and a fixing detail the engineer has accepted, before fabrication starts. Asking for that in the specification is cheaper than finding the gap at inspection.

Scotland, Wales and Northern Ireland

The 2013 edition is for use in England. Building regulations are devolved: Wales publishes its own Approved Document K, and Scotland and Northern Ireland use their own technical guidance. We have not read those for this sheet, and they may use different figures or rules. Do not carry the England figures into a project elsewhere without checking the local document.

Six checks before a balustrade drawing is issued

• Building and location: find the row in Diagram 3.1 that matches the building category and where the guarding is.
• Under-fives: decide with building control whether the 100 mm sphere and no-horizontal-rails points apply.
• Handrail: height from the pitch line and from the floor, one side or both, and whether the building type brings the extra points in paras 1.35 and 1.36.
• Glass: if any glass is used, check Section 5 and ask the engineer and glazing supplier for build-up and fixing.
• Loads: the engineer names the load category; evidence for the system comes before fabrication.
• Fire and access: check Approved Document B for balcony materials and escape stairs, and Approved Document M for accessible routes. Neither is covered here.

Guarding to [stair / landing / balcony], finished height [ ] mm, not less than Approved Document K (2013, England) Diagram 3.1 for [building category and location]. [Where children under five may use the building: no opening to pass a 100 mm sphere; no horizontal rails (paras 1.39, 3.3).] To resist not less than the loads in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1, category [ ], as set by [structural engineer]; calculations or test evidence and fixing detail agreed before fabrication.

Handrail to [stair reference], top [ ] mm above the pitch line (900 to 1,000 mm, Approved Document K 2013 para 1.34a) and [ ] mm above landing floor level, on [one side / both sides; both if the stair is 1,000 mm wide or more]. [Buildings other than dwellings: continuous; section to Diagram 1.13; contrasting, not highly reflective; end finished to avoid catching clothing (paras 1.35, 1.36).]

Glazed guarding to [location]: [laminated / toughened laminated] glass [ ] mm, to the structural engineer's design for the loads in BS EN 1991-1-1 with its UK National Annex, category [ ]. Critical locations (Diagram 5.1): para 5.4 [Class 3 of BS EN 12600, or the class the engineer states]. Fixing, edge and base detail by [structural engineer / glazing specialist], agreed with building control before fabrication.

Standards and sources

• Approved Document K: Protection from falling, collision and impact, 2013 edition, England: read in full on 5 November 2026.
• gov.uk: Building Safety Regulator call for evidence on Part K (19 Oct 2026): a review; current guidance stays in place.
• BS EN 1991-1-1 and UK National Annex; PD 6688-1-1; BS 6180; BS EN 12600; BS 6206: named in the document; not read.

Questions we are asked

How high must a balustrade be in England?

It depends on the building and the location. Approved Document K (2013 edition) Diagram 3.1 gives at least 900 mm for stairs, landings and internal floor edges in a single-family dwelling, and 1,100 mm for its external balconies, including Juliet balconies. In residential, institutional, educational, office, public and retail buildings it gives 900 mm for flights and 1,100 mm elsewhere.

What is the 100 mm sphere rule?

In a building that may be used by children under five during normal use, no opening in the guarding may let a 100 mm sphere pass through, so a child cannot be held fast (Approved Document K paras 3.3a and 1.39a). The same paragraphs ask you to avoid horizontal rails that a child could climb.

Does the 100 mm rule apply to every balustrade?

The document ties it to buildings that may be used by children under five during normal use. It does not list which building types qualify, so agree with building control at design stage rather than assuming the rule does not apply.

How high should a stair handrail be?

The top of the handrail is 900 to 1,000 mm from the pitch line or floor (para 1.34a), with a handrail on both sides if the stair is 1,000 mm wide or more (para 1.34c). Buildings other than dwellings and common stairs in some blocks of flats have further points in paras 1.35 and 1.36.

What loads must a balustrade resist?

Approved Document K says guarding should resist at least the loads in BS EN 1991-1-1 with its UK National Annex and PD 6688-1-1 (para 3.2c). We state no load figures here. The structural engineer chooses the category and checks the posts, fixings and supporting structure.

Do these figures apply in Scotland, Wales or Northern Ireland?

No. The 2013 edition is for use in England. Wales publishes its own Approved Document K, and Scotland and Northern Ireland have their own guidance. Check the document for the nation your project is in.