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The Level Entry

Notes on thresholds, kerbs and the way into a building

What an Entrance Photo Hides About Step-Free Access

A photograph of a building entrance hides the threshold lip, the landing depth and the door leaf width. These are the three measurements a visitor meets first.

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EN-003EN-002EN-001

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EN-001 · Entrances and thresholds
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A wheelchair user's front wheel resting against a 20 mm threshold lip at a building entrance, low camera angle at floor level, overcast daylight from the open doorway.
Plate EN-001 A front wheel meets the threshold lip that decides step-free access.

A photograph of a building entrance cannot show whether the route is step-free. It hides three measurements that decide the answer: the height of the threshold lip, the depth of the landing in front of the door, and the clear width of the door leaf. A visitor meets all three before they meet anyone inside.

An architectural photography guide can set out how to frame a threshold, a landing and a door in one frame, and how to correct verticals so the opening reads square. It cannot put a number on the lip. That number comes from the drawing, the survey or a level laid on the paving.

What height of lip stops a wheel?

A vertical change of more than 15 mm stops most wheels. Approved Document M, the part of the Building Regulations for England that covers access to and use of buildings, treats 15 mm as the upper limit for a threshold that a wheelchair user can cross without assistance. Between 5 mm and 15 mm the edge has to be chamfered or rounded so the wheel climbs rather than jams. Below 5 mm the change is generally treated as flush.

A camera does not record this. A 20 mm upstand and a 4 mm upstand look the same in a photograph taken from standing height, and both look like a clean line where the paving meets the frame. The lip only becomes visible when the lens drops to the level of the threshold, or when something with a known size sits beside it.

For a level entry, the finished floor inside and the external surface outside should meet within that 15 mm band, with no step and no raised strip. Where a door sits on a raised threshold bar, the bar itself is the measurement. Where a mat well or a drainage channel interrupts the line, the gap and its cover count too.

How deep does a landing have to be in front of a door?

A landing in front of a door needs to be at least 1500 mm deep by 1500 mm wide where the door opens towards the user, and at least 1200 mm deep where it opens away. These figures come from Approved Document M and from BS 8300-1:2018, the British Standard for the design of an accessible and inclusive built environment. The depth matters because a wheelchair user needs to pull back, turn and approach the leaf without rolling off an edge.

A photograph flattens depth. A landing 900 mm deep and a landing 1800 mm deep can occupy the same area of a frame, and the paving pattern gives no scale. The landing also has to be level, or fall away at no more than 1 in 50 in any direction, so that a wheel does not run and a foot does not slide. A 1 in 12 ramp is a different element: it is the approach, not the landing, and it needs its own level platform at the top.

Where the landing is bounded by a kerb, a channel or a change in surface, the boundary is part of the measurement. A dropped kerb that is not flush with the carriageway breaks the route before the door is reached. The highway authority's own published figures for the crossing point give the level difference at the kerb line, and that figure is the one to check.

What clear width of door counts as step-free?

A clear opening width of at least 900 mm counts as step-free for a wheelchair user in most situations. Approved Document M gives 900 mm as the figure for a new dwelling's entrance door and for doors on an accessible route in non-domestic buildings, and BS 8300-1:2018 uses the same order of measurement. The clear width is measured between the face of the open leaf and the opposite frame or stop, not between the frame reveals.

A photograph shows the leaf, not the clear opening. A 1000 mm door hung on a frame with a 100 mm stop can deliver less than 900 mm of clear width, and the difference is invisible in a picture. Door furniture, a closer arm, a threshold strip or a second leaf of a pair all reduce the figure further. The measurement is taken with the door open at 90 degrees, which is also the position a photographer is least likely to record.

The three measurements a visitor meets first

The threshold, the landing and the door leaf are met in that order. A visitor arrives at the lip, crosses the landing, then passes through the opening. Each one can fail on its own, and each one can look correct in a photograph.

A useful test is to ask what the picture was taken to show. An entrance photographed from the pavement at eye level records the facade, the sign and the glazing. It does not record the 18 mm upstand at the door, the 1100 mm landing, or the 780 mm clear opening behind a heavy leaf. Those three numbers decide whether the entrance is step-free, and none of them is visible from where the camera stood.

Why the Equality Act 2010 changes the question

The Equality Act 2010 places a duty on service providers to make reasonable adjustments so that disabled people are not placed at a substantial disadvantage. For a building entrance, that duty can require a threshold to be altered, a landing to be extended or a door to be widened, even where the building was built to the standards of its time. The Act does not set the 15 mm, the 1500 mm or the 900 mm figures. Those come from Approved Document M and BS 8300-1:2018. The Act sets the obligation to act.

A photograph taken for a brochure or a listing does not discharge that duty, and it does not record whether the duty has been met. It records the appearance of the entrance on one day, in one light.

What to measure before you rely on a picture

Take a level and a tape to the entrance. Record the height of any lip at the threshold, in millimetres. Record the depth and width of the landing, in millimetres, and the fall across it. Record the clear opening width of the door with the leaf at 90 degrees. Note the level difference at any dropped kerb on the approach.

Compare each figure with the source that applies: Approved Document M for the building work, BS 8300-1:2018 for the design guidance, the Equality Act 2010 for the duty, and Changing Places guidance where a changing places facility is claimed. A photograph can support the record. It cannot replace it.

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A joiner's workshop bench in daylight, with a dimensioned pencil drawing in millimetres beside a half-assembled oak frame, chisels laid out, shot from above at close range.

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A wheelchair wheel passing through an interior doorway at floor level, a plain corridor floor and a door frame visible, soft daylight from a window further along the corridor.
The point where a straight corridor becomes a turn into a doorway.

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