Accessibility Requirements in BR18: Step-Free Access & Layout

Accessibility is one of the requirements in the building code with the worst habit: you often discover it too late. An entrance has to be step-free, a door has to be passable by a wheelchair user, a building above a certain height has to have a lift — and each of those details has consequences for the placement of stairs, terrain regulation, floor heights and layout. Drawn in late, they get drawn in expensively.

The tricky thing about the accessibility requirements in BR18 is that they don’t apply the same way to everything. What gets triggered depends on the building’s use and its number of storeys. A single-family home, a multi-storey residential development and an office building are not hit by the same set of rules. So the first step isn’t to look up a door dimension, but to clarify which category your project lands in — because that determines which requirements are in play at all.

Why accessibility requirements trigger differently

The building code fundamentally distinguishes between construction for private residence and construction where the public or many users move about. The more a building is used by people other than the residents themselves, the stricter the accessibility requirements become. That’s the logic behind why an office building, a shop or a rental property with shared access routes typically has to meet more than a detached house.

So the use category determines the starting point. The number of storeys adjusts it further — particularly for the lift obligation, where it’s the number of storeys that triggers the requirement. That’s why it’s worth establishing early whether the project actually has the use and the number of storeys you think it does. This is precisely the kind of assumption that should be verified against the planning conditions and the use codes in BBR (the Buildings & Dwellings Register) before you draw any further — and it’s part of the broader clarification covered in the overview of BR18 requirements for new construction and when they trigger.

Rule of thumb: the more outside users the building is intended for, the more you should expect step-free access and accessible layout to apply in full — even if the building is small.

Step-free access — from pavement to entrance

Step-free access is the core principle. It means you have to be able to get from the ground and into the building without having to negotiate steps. The requirement isn’t only about the threshold itself, but about the whole access route: the paving, the gradient of any ramps, and that there are no level changes a wheelchair user or a person with a rollator can’t manage.

In practice there are two classic pitfalls:

• The terrain. A sloping site makes step-free access harder, and terrain regulation or ramps can eat into both the building zone and the budget. It has to be thought into the site plan, not solved afterwards.
• The threshold. Even a small step at the entrance door can break with step-free access. The detail lies in the junction between floor, door assembly and external paving — and it has to be designed deliberately.

Ramps are a legal solution, but they have limits on gradient and typically require landings on longer runs. A ramp that’s too steep does not meet the requirement, no matter how neat it looks. The specific gradient limits should be looked up in the current edition of the building code, since that’s where the precise figures are stated.

Door widths and internal passage

Step-free access doesn’t stop at the front door. Internally, the relevant doors and passages have to have a clear width that makes them usable for wheelchair users — this typically applies to access to the rooms and functions the user needs to reach. Note that it’s the clear passage width that counts, not the frame dimension: the door leaf, stop and handle eat into the opening you can actually pass through.

This has concrete consequences for the layout:

• Circulation areas and turning spaces have to be large enough for a wheelchair to manoeuvre — particularly in front of doors and in bathrooms.
• Narrow corridors and tightly packed layouts that look fine on paper can in practice fail on turning diameter.
• In multi-storey construction it also applies to the shared access routes: stairwells, distribution corridors and access to shared functions.

The precise figures for clear width and turning area should be verified in the building code’s current guidance, since they are what a building case officer holds the project up against.

The lift obligation in new construction

The lift obligation is the requirement that most often surprises developers, because it can shift a whole project’s economics. The principle is that buildings above a certain number of storeys have to have a lift, so that all storeys can be reached step-free — it’s no use having step-free access at ground level if the dwellings on the upper storeys can only be reached by a staircase.

That means the number of storeys is a design parameter, not just an outcome. The difference between a development just below and just above the lift threshold is the difference between having to accommodate a lift shaft, a machine room and the associated fire and structural considerations — or not. If you land right on the threshold, it can pay to run the numbers on both scenarios before the storey plan is locked.

The specific storey threshold for the lift obligation depends on the use and is set in the building code. It should be checked in the current edition for your exact building type, since the threshold is not the same for all categories.

Accessible layout within the dwelling

Beyond access and passage, BR18 imposes requirements on the layout itself — that dwellings and habitable rooms can be used by people with reduced functional capacity. This mainly hits wet rooms and bathrooms, where there has to be space to manoeuvre and to mount aids if the need arises. This is where “accessible layout” in a dwelling becomes concrete: not that everything has to be pre-installed, but that the layout doesn’t block it.

Accessibility also interacts with the other layout requirements. A bathroom has to have both manoeuvring space and meet the other requirements, and a dwelling must at the same time live up to the requirements on light and air. It’s rarely a single requirement that dictates a room — it’s several at once. The interplay with the daylight and indoor-climate requirements for dwellings and habitable rooms in BR18 is worth keeping in mind when the layout is laid out, so you don’t optimise one requirement and fail on another.

When accessibility should be clarified — and by whom

Accessibility is a discipline that belongs right at the start of the design phase, alongside building rights, use and volume. It’s cheap to incorporate at sketch level and expensive to fix once façades and plans are fixed. The sequence is decisive: clarify use and number of storeys, establish whether the lift obligation is triggered, and then let step-free access and internal passage shape the site plan and layout from the start.

For larger and more complex buildings, accessibility also forms part of the documentation that has to accompany the building case, and can touch the roles where a certified structural engineer and fire consultant are required by law depending on the building’s complexity. Although accessibility does not in itself trigger a certified consultant, it ties into the overall compliance assessment of the project — and that assessment should be done early.

How to bring accessibility in from the first sketch

The manual exercise is manageable but time-consuming: establish use and number of storeys, look up the current requirements in the building code, assess whether the lift obligation is triggered, and test whether the layout really leaves room for step-free access and turning area. This is the kind of groundwork that either saves or costs hours later.

In Project Development in Arcili the early clarification is gathered in one place: from cadastral parcel and use to volume and planning conditions, so that the assumptions that determine which accessibility requirements are in play are out in the open early in the process instead of surfacing as surprises late on. It doesn’t replace the architect’s or engineer’s assessment — but it removes the initial legwork, so the expertise can be spent on the real decisions.

Want to see how it works on a concrete project? Book a walkthrough and we’ll show you the flow from cadastral parcel to project brief.