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Drawing office notes
Balustrade height regulations for houses and commercial buildings.
In England, guarding beside the stairs and landings of a house should be at least 900 mm high. A balcony or roof edge needs 1100 mm, even on a house, and offices, shops and schools need 1100 mm everywhere except alongside a flight. Those figures come from Diagram 3.1 of Approved Document K. Here's the whole table, then the gap, climbing, strength and glass rules we check before a balustrade is drawn.
The law, then the guidance
Requirement K2 of the Building Regulations 2010 says barriers must be provided where needed to stop people falling: on stairs, ramps, floors, balconies and roofs people can reach, and round light wells and basement areas next to a building. It gives no heights. Those are in Approved Document K, 2013 edition, the government's guidance for England. Stick to it and building control will normally accept it, but it's not a guarantee. Our Part K stair note covers rise, going and handrails; this one stays with the balustrade.
When a drop needs guarding
In a dwelling, guarding should stop people being hurt by a fall of more than 600 mm. In any other building it should stop a fall of more than two risers, or 380 mm where the change in level isn't part of a stair.
Paragraph 3.1 lists the places: floor edges (including under an opening window), galleries, balconies, roofs, sunken areas next to the building, and anywhere else people can get to. The document says a public building may need a higher standard than a house, because visitors don't know their way round. Where only maintenance staff go, less may be accepted.
Minimum heights from Diagram 3.1
| Building | Where | Minimum |
|---|---|---|
| Single family dwelling | Stairs, landings, ramps, edges of internal floors | 900 mm |
| Single family dwelling | External balconies, Juliet balconies included, and edges of roofs | 1100 mm |
| Factories and warehouses (light traffic) | Stairs and ramps; landings and edges of floors | 900 mm; 1100 mm |
| Residential, institutional, educational, office and public buildings | Flights of stairs; all other locations | 900 mm; 1100 mm |
| Retail | Flights of stairs; all other locations | 900 mm; 1100 mm |
| Assembly | Within 530 mm in front of fixed seating; flights; everywhere else | 800 mm; 900 mm; 1100 mm |
| Glazing, all buildings | At opening windows (roof windows in loft extensions: see Approved Document B) | 800 mm |
Houses are the only place 900 mm is enough anywhere other than on the stair itself. A gallery inside a house is the edge of an internal floor, so 900 mm; put the same gallery in an office or shop and it needs 1100 mm. A balcony on a house needs 1100 mm too, and so does a Juliet balcony across French doors.
In commercial buildings 900 mm applies along the flight only. Where the balustrade leaves the stair and runs round the landing or stairwell, our drawing steps it up to 1100 mm. Diagram 3.1 has no row for the shared stairs and landings in a block of flats. So agree the figure with building control before anything is made.
Halfway through and want the sums done for your own stair? Ring the drawing office or leave your number below.
Call 07460 042 774Where the height goes missing on site
Decking or tiles laid after the balustrade goes in lift the floor and eat into the height, so we ask what the finished surface will be and set out from that. A planter or bench pushed against the guarding later can become a step for a child, which brings in the next rule.
Gaps and climbing where young children may be
Paragraph 3.3 covers buildings that children under five may use. Every opening has to stop a 100 mm sphere passing, and the guarding should be hard to climb, which the document puts as avoiding horizontal rails. Paragraph 1.39 says the same for stairs.
On a metal balustrade the sphere check isn't just about bar spacing. It also covers the gap under the bottom rail, at the wall or newel, and the triangle between a raked bottom rail and the nosings. Horizontal rails or wires work against the climbing advice where small children may be about, so we raise it at the survey. Upright bars and the problem goes away.
How strong it has to be
Paragraph 3.2 asks for guarding that resists at least the loads in BS EN 1991-1-1, with its UK National Annex and PD 6688-1-1, and points to BS 6180 for designing barriers and infill panels. BS 6180:2011, Barriers in and about buildings, is still current (BSI says it's under review). The 2011 revision added a table of minimum sideways loads for parapets, barriers and balustrades, and there's an annex on bolting glass.
We don't print load figures here. The right one depends on how the space is used, so a balustrade that suits a house landing can be too light for a shop floor. Loads and fixings go on our technical drawings, because a post can only be as strong as the concrete, steel or joist it's bolted into.
Glass, windows and Juliet balconies
Where glass is used in the guarding, paragraph 3.2 also sends you to Section 5. In critical locations the glass should break safely, be robust or in small panes, or be permanently protected; for safe breakage it names Class 3 of BS EN 12600 or Class C of BS 6206. On a glass balustrade the thickness and the clamping follow the BS 6180 design.
Paragraph 8.2 says that where someone could fall from a window above ground floor, the window needs opening limiters or guarding. Once the window becomes a door with a Juliet balcony, the 1100 mm figure applies.
Checking it with building control
Every figure here is a minimum from guidance. Building control has the last word on your job, and in East Grinstead that's usually Mid Sussex District Council's building control team, though another building control body can be used.
Our drawing shows the height, the bar spacing and every fixing, and it's yours to hand in. See the systems we make on the balustrades page or, for stairs indoors, internal balustrade. Surveys round East Grinstead are free, or send the drop, the run and a photo through our quote form.
Questions we are asked about balustrade heights
Is 900 mm high enough for a balcony balustrade?
Not outdoors. Diagram 3.1 gives 1100 mm for external balconies, Juliet balconies and roof edges, on a house as anywhere else. In a house, 900 mm covers stairs, landings, ramps and internal floor edges.
How high should a balustrade be in an office or shop?
At least 900 mm along a flight and 1100 mm everywhere else, including landings, mezzanines and galleries. In assembly buildings, guarding within 530 mm in front of fixed seating can be 800 mm.
When does a raised deck or patio need a balustrade?
In a house, anything over a 600 mm drop needs guarding. In other buildings it's a fall of more than two risers, or 380 mm away from a stair. Whether your deck comes under the Building Regulations at all is worth asking building control first.
Are horizontal bars or wires allowed?
If under-fives could use the building, the advice is to avoid horizontal rails and size every gap so a 100 mm sphere is stopped. Elsewhere that paragraph doesn't apply, though height and loads still do. Our wire infill page shows the options.
What is BS 6180?
BS 6180:2011, Barriers in and about buildings, is the code of practice Approved Document K points to for designing barriers and infill panels. BSI lists it as current and under review.
Sources: Approved Document K, 2013 edition (gov.uk): paragraphs 1.38 to 1.41, Section 3 with Diagram 3.1, Section 5 and paragraph 8.2. Building Regulations 2010, Schedule 1, requirement K2 (legislation.gov.uk). BS 6180:2011, Barriers in and about buildings (BSI product page; we quote only what BSI publishes there). Mid Sussex District Council, building control applications. Checked: 10 October 2026.