In October, a floor area becomes a tax bill. In most firms, nobody owns the floor area.
Start with the term. From 1 October 2026 there is a new tax in England called the Building Safety Levy. It is charged on new homes, and the money goes towards fixing historic fire-safety defects in buildings somebody else built — the government expects to raise around £3.4 billion over ten years. It is not a fee for a service but a tax, calculated on the size of what you build.
What sets it off, and when
It attaches to the building control application — the application for approval that the works comply with the Building Regulations, a separate exercise from planning permission, usually handled by a different person in a different month. Not the planning consent. The building control application.
It only bites on what the regulations call a major residential development: ten or more new dwellings under the planning permission, or thirty or more bedspaces in purpose-built student accommodation. And you cannot duck the threshold by splitting a scheme into several smaller applications, because the test is applied to the planning consent they sit under.
The charge is per square metre of new residential floorspace, measured as gross internal area — the floor area inside the external walls, which is not the number on the sales brochure. The rate is set district by district in a table attached to the regulations, weighted to local house prices. It runs from £12.70 a square metre in County Durham to £100.35 in Kensington and Chelsea. That rate is halved if the scheme sits on previously developed land — land that has had a building on it at some point since 1 July 1948, with carve-outs for farm buildings, minerals extraction and landfill, and only if 75 per cent of the land inside the planning red line qualifies.
Ask who in your business could answer that, this afternoon, for the site you started last month.
The date on the application is now worth money
The levy is not retrospective: applications made before 1 October 2026 are not chargeable, even if amended afterwards. So for every scheme you already hold planning for, the date you file the building control application has pounds attached to it. In most firms that date is whatever day somebody’s inbox got round to it.
Then the part that catches people. The levy falls due on the earlier of completion or first occupation of the first residential building covered by that application — and the whole application becomes payable at that moment, including buildings you have not started. Put a five-phase scheme through as one global application and finishing phase one bills you for all five. Split it into staged applications and you pay in tranches instead. Same total, very different cash flow, and the decision gets made by whoever fills in the form.
If it is not paid, building control must not issue the completion certificate. No completion certificate, no occupation. No occupation, no sale. A piece of tax admin now sits directly on the path to being paid.
What the office actually has to produce
Basic information goes in with the building control application. Fuller information with the commencement notice — the notice you already give to say work is starting — and that is where the floor areas, the exempt units and the land history have to be stated. The collecting authority, which is your local council even where a private building control body or the Building Safety Regulator does the inspecting, then has five weeks to issue a liability notice saying what you owe. You pay. They issue a payment certificate within two weeks.
Which means somebody in your office has to commit, in writing, to a floor area for a scheme that has not been built, a count of which units are exempt, and a claim about what stood on the land seventy years ago. Then defend all three, months later, against a design that has moved on twice.
Where does the floor area live today? In a schedule of areas the architect produced at planning stage. In a spreadsheet the quantity surveyor keeps, which is slightly different. And on a brochure, measured a different way, which is the one people quote in meetings.
Three numbers, no owner. That has been survivable because nothing turned on it. Now something does.
What a fix looks like
Small, as usual. Not a levy module bolted onto a platform.
One row per plot on the job record: plot number, tenure, gross internal area, the drawing number and revision the area came off, who took it off, when. Then the scheme facts once: the previously-developed claim and its evidence, the planning reference, the building control application reference and date, the commencement notice date, the liability notice, the payment date, the certificate. Half a screen, hanging off your existing job number.
The value is not the arithmetic; a spreadsheet does that. The value is provenance and a diary. When the design changes you can see which plots moved and whether what you declared is still true. When the liability notice lands, you can check it against your own figure instead of paying whatever the council typed. And the phase-one payment gets forecast rather than discovered.
The honest version: the levy is not creating a problem in your business. It is putting a price on not knowing your own floor areas.
Where this doesn’t apply
Quite a lot of places. If you build commercial, industrial, fit-out, civils or maintenance work, this is nothing to do with you. If you are a subcontractor, the bill sits with the client named in the building control application — although expect that client to start chasing you for area take-offs faster than they used to. Under ten dwellings on the permission: out. Non-profit registered social housing providers: out, and social housing units in a chargeable scheme count towards the ten but are not charged. Care homes, hotels, hospitals and school accommodation: out. Wales, Scotland and Northern Ireland: England only.
And if you turn out three hundred homes a year with a development team and a cost plan that already tracks area per plot by revision, you do not need me. Add three columns, set a reminder, move on.
The firms this catches are in the middle. Big enough to clear ten units regularly, not big enough to employ someone whose job is knowing which revision is current. If you are not sure which of those you are, that is usually the answer.
Get in touch.