Construction AI: the second stair becomes law in a month, and the takeoff that prices itself as you draw

Here's the dated fact to put in front of anyone running a tall residential scheme. The amendment to Approved Document B that requires a second common staircase in blocks of flats with a top storey of 18m or more comes into force on 30 September 2026. It was published on 29 March 2024 with a long run-in, and that run-in ends this month (Pinsent Masons, RICS).

The headline gets the attention, but the transition is where the money sits. To keep a scheme on the old single-stair rules, an application, a building notice, an initial notice or a full-plans building control application, has to be in before 30 September. And the work has to be sufficiently progressed, either before that day or within 18 months of it, so before 30 March 2028 (Constructionline). What "sufficiently progressed" means on site is the bit people gloss over: permanent foundation pours or piling actually started, not a cleared plot and a programme that says you meant to. So there's a real scramble on right now to get applications banked before the 30th, and a second judgement after it about whether the ground work counts. Get either wrong and the stair count changes, which changes the core, which changes the floorplate.

And it isn't only the stair. The same package brings design provisions for evacuation lifts, tighter travel-distance limits, and evacuation alert systems in residential buildings over 18m (RICS). Where AI genuinely earns its place here is unglamorous: reading a drawing set against the new provisions to flag the misses before a building control officer does, and keeping a clean record of which rule set a building sits under and why. Think of it like the MOT paperwork on an old car. Nobody enjoys it, but the day you sell, the folder that proves what was done and when is worth more than the polish. That's what the golden thread is really for, and this deadline is the moment it stops being a slide and starts being the thing that decides whether your single-stair design is defensible. The person who carries that is the technical lead trying to prove, two years on, that the foundations were in on time.

Today's action: For every tall residential job near the line, write down the application date and the exact state of the groundworks, and keep it somewhere that survives a staff change.

Togal.AI launched Assemblies on 29 August 2026. The idea is straightforward and, I think, overdue: as an estimator takes off a drawing, the software builds the bill of materials alongside the measurement, material, labour and equipment together, rather than leaving someone to rebuild it all in a spreadsheet afterwards. Drywall is the starting trade, and you can either use Togal's templates or build your own assemblies to match how your firm actually prices (Togal.AI, Highways Today).

Drywall first is a deliberate choice, and a sensible one. A wall is never just its length or its area. It's studs at a spacing, track top and bottom, one or two or three layers of board, a fire rating, sometimes insulation, sometimes a service void, and the labour to hang and finish all of it. Embed that logic and the takeoff stops being a measurement and becomes a priced scope. That's the shift worth watching, and Togal say drywall is the start rather than the limit.

One point of precision, because the words matter. This is a point solution, a sharp one for a single trade, not challenger construction software, the broad AI-first platforms taking on the big incumbents across a whole project. It does one job and does it well, and it belongs here in Tools and Platforms. The category only means something if we don't pin it on everything that ships with an estimate attached. What this does for the person doing the paperwork is real enough on its own: it takes the double-handling out of the estimate, so the estimator spends the saved hour judging the number instead of retyping it.

The procurement filter: When you trial it, price a job you already know the answer to, and check whether the assembly logic is yours to edit. If the templates can't bend to how you actually estimate, the saving evaporates on the second job.

Put the two together and you get the shape of where this year's actually going. On one side, regulation keeps raising the bar on the record: the second-staircase deadline isn't only a design rule, it's a demand that you can prove, later and under pressure, which rules your building was built to and when the work started. On the other, the useful AI keeps turning up at the task edge, in the estimator's takeoff, not in some grand platform that promises to run the firm. Both point the same way. The value is in the boring, provable middle, the scope that's priced as it's drawn and the record that holds up when someone asks.

The comparison only goes so far, but it's a bit like a good site diary. Nobody wins an award for it, and it's the first thing anyone reaches for when a job goes to dispute. The firms that treat the record as a product, not an afterthought, are the ones this deadline will be kind to.

For your board pack: Name one person who owns the "which rule set, proved how" record for every live tall-residential scheme, before 30 September, not after.