The building was fine. I couldn't work out where to go.

Four signs in the foyer.

One is a directory listing every room in the building. One is an arrow to something called Suite B. One is a laminated notice about a fire door. One is a welcome board with the day's events on it, two of them crossed out in biro.

Not one of them tells me where to check in - and not one tells me where the toilet is.

The building has done nothing wrong. Level threshold, wide doors, the lift works, the lighting's inside tolerance.

It would pass an audit - and on those terms it deserves to.

And I'm sat in that foyer five minutes later with less left than I walked in with.

Cognitive access is what it costs you to work out where to go

Cognitive is the fourth of the six domains I assess, and it asks one question: can someone understand and act on information without excessive mental load?

Wayfinding logic. Signage simplicity. Information hierarchy. How many things are competing for your attention at once.

What I'm really answering is whether you can navigate without exhausting your mental bandwidth.

The Physical domain asks whether there's a route. This one asks whether you can find it - and what finding it takes out of you.

Every junction without a sign is a decision. Which way, have I passed this already, am I going round in circles.

Each one spends something, and nobody's counting them.

There is a standard for this. PAS 6463:2022, Design for the mind: neurodiversity and the built environment, effective from 31 October 2022. It's the first British standard written around how neurodivergent people actually process a space, and it turns on three principles: Clarity, Control and Calm.

Hardly anyone assesses against it - it isn't in Approved Document M, and you can't measure it with a tape.

Three wrong turns is a measurement

So I measure it a different way.

I walk in cold and try to reach a named facility without asking anyone. Usually the accessible toilet - sometimes the lift, sometimes a room on the second floor.

I record the wrong turns, the hesitations, and how long it took.

"Three wrong turns, and no directional signage until the second-floor landing" is a finding. It's repeatable, and it isn't an opinion about how a building feels.

Then I photograph the place it went wrong. The junction with nothing on it. The two identical corridors. The sign that names somewhere without saying which way it is.

The signs themselves get measured against BS 8300, because there are real numbers here and most buildings have never checked them.

Text and board need at least 30 points of difference in light reflectance value - and so do the board and the wall behind it. White text on a glass sign on a white wall fails twice.

Character height follows viewing distance: around 50mm to be read at two metres, 150mm at six. So the tidy 10mm room numbers on the drawing are legible at 30 centimetres with good sight, and decorative after that.

Signs belong between 1400 and 1700mm, centred on 1500. At two metres they look neat on a plan - and they're out of my eyeline completely.

They go on the latch side, and not on the door itself. A sign on an open door is a sign in a cupboard.

One room gets one name: pick between Toilet, WC and Lavatory and use it everywhere, because a visitor who's already tired is now translating as well as navigating.

None of that is taste. Under the Equality Act 2010 a failure to provide an auxiliary aid can be discrimination - and information you can't read is information you haven't been given.

A loud, bright room makes your signage unreadable

Here's the part I've never heard another consultant say out loud.

Cognitive load is downstream. Fix the Visual and Auditory domains and the Cognitive score usually rises on its own, without anyone touching a single sign.

The flickering light isn't only a visual finding. The hall that rings for a second after every footstep isn't only an acoustic one.

Both of them charge you for being in the room - and they charge it to the same account you were about to spend on reading a sign and choosing a corridor.

I work to under 0.6 seconds of reverberation where people are meant to concentrate, and under 40dB of background noise in a quiet working area, 45 in general occupied space. Those are my working figures rather than clause numbers, and I say so in the report.

A room that breaches them makes the wayfinding harder for everybody in it - including the people who'd have managed it fine on a quiet morning.

A busy carpet and a wall of posters compete with the one sign that's actually working. The skill is holding functional contrast high on doors, signage and stair nosings while keeping decorative contrast low everywhere else.

So I don't assess the six domains in separate chapters and add up the scores. I assess them the way they land - on one person, in the same ten minutes, out of the same finite capacity.

A building can pass its wayfinding check at nine in the morning and fail it at two, when the cafe's full and the blinds are up.

The signage didn't change.

I built this column because I kept failing at it

The six domains are mine, built out of decades of working out why places that let me in still sent me home early. I told that story properly in the first post in this series.

This is the domain where I stopped being only the auditor.

I'm autistic and I have ADHD. My brain doesn't do the background filtering that other people's does for free, so the hum, the flicker and the fourth sign all arrive at the same volume as the thing I'm trying to think about.

Four undirected decisions and my working memory is full.

That isn't a gift and I'd swap it tomorrow. What it does mean is that I notice the load while it's happening - and I can write down the point it started, which is the point a consultant with a lux meter walks straight past.

There's a whole industry telling neurodivergent people their brains are a secret advantage. It's selling something - usually to the people it's hardest on.

The useful version is smaller and duller. I'm a reasonably well-calibrated instrument for one domain, and I show my working so nobody has to take my word for it.

There's nowhere to stop, and that's a finding

When a space does overload someone, they can leave and miss what they came for, or push through until they shut down.

In most buildings that's the whole menu.

The third principle in PAS 6463 is Calm, and it means somewhere to withdraw and recover before overload rather than after it. Its absence is a finding in its own right, and I write it as one.

If a venue tells me it has a quiet room, I go and check.

Is it actually quiet, with a dB reading to say so. Is it actually dimmable. Is it actually available on the day - or is it a store cupboard with a laminated sign on the door and a stack of chairs in it.

A quiet room that fails its own sensory check is worse than no quiet room, because now you've made the journey for nothing.

And before anyone says it

Yes, I know. You can't dumb everything down.

Nobody's asking you to. Plain language has nothing to do with the reader's intelligence - it's about how much capacity they've got left by the time they reach your sign, and everyone's is lower when they're late, lost or unwell.

Clarity usually means putting less in front of people rather than writing it simpler.

At the entrance, name the major destinations. At each junction, say which way they are. At the door, confirm they've arrived.

The directory of two hundred rooms in the foyer isn't extra service - it's every decision in the building handed to someone at the exact moment they're least able to make one.

Most of what you'd take out was never carrying meaning anyway - it was carrying somebody's job title and a cancelled event from March.

And when this gets fixed properly, the people it helps most aren't disabled at all. They're your new starter in week one, your delivery drivers, the parent with a pushchair and a toddler, and everyone who's ever walked in for the first time and been too embarrassed to ask.