Two changes landing this week: what do they mean for residential developers?

There are two dates I think residential developers need to have firmly in their diaries this week. 30th September & 1st October

They relate to two very different changes, but both have something in common: they introduce additional requirements and costs at a time when bringing residential development forward is already becoming increasingly challenging.

As an architect working with developers in and around Reading and Wokingham, I'm particularly interested in what these changes mean for the small and medium-sized developer.

There is a lot of discussion around building safety — quite rightly. The Building Safety Act and subsequent changes to fire safety requirements have been driven by the need to make buildings safer for the people who live in them.

But there is another part of the conversation that is important too.

Can developments continue to be financially viable and actually get built?

30 September: the second staircase requirement

From 30 September 2026, new residential buildings in England with a storey at least 18 metres above ground level will be expected to have a second staircase under the updated Approved Document B guidance. GOV.UK

The intention behind the change is clear.

A second staircase provides an additional means of escape and supports evacuation in the event of an emergency. It forms part of the wider changes to fire and building safety that have followed the Grenfell Tower tragedy and the Building Safety Act. GOV.UK

From a design perspective, however, adding another staircase isn't simply a case of drawing another line on a plan.

It can affect the core of a building, circulation, apartment layouts, net-to-gross efficiency, structural design and ultimately the number and size of homes that can be delivered.

And that matters because development appraisals work on very fine margins.

If you lose saleable floor area to additional circulation or cores, or have to redesign a building around a different arrangement, the consequences can extend well beyond the architectural drawings.

There are transitional arrangements, which are important for projects already in the system. Government guidance states that the relevant building regulations approval needs to have been obtained before the change takes effect and the work must be sufficiently progressed by 30 March 2028 to benefit from the transitional provisions. GOV.UK

For developers with projects around the threshold, therefore, understanding exactly where a scheme sits now is important.

1 October: the Building Safety Levy

The following day brings another significant change.

From 1 October 2026, the Building Safety Levy comes into operation in England.

This is a charge on qualifying new residential development, with the money being used to support the remediation of building safety defects. GOV.UK

One of the points I think is particularly relevant to the SME development market is the threshold.

The levy applies to major residential development, defined as 10 or more new dwellings.

Developments of fewer than 10 dwellings are exempt from the levy, subject to the wider rules and exemptions. The threshold is linked to the development covered by the planning permission, so developers cannot simply divide a larger development into separate applications to avoid the levy. GOV.UK

That means a nine-home scheme and a ten-home scheme could sit on opposite sides of the levy threshold.

And once you cross that threshold, the calculation is based on floorspace rather than simply the number of homes.

So what could that actually mean in Wokingham?

This is where the numbers become more tangible.

The Government has published different levy rates for each local authority.

For Wokingham, the current rates are:

£22.49 per m² for previously developed land and £44.98 per m² for land that is not previously developed. GOV.UK

The levy is calculated using chargeable residential floorspace, measured on a Gross Internal Area basis. Certain communal areas can also form part of the chargeable floorspace. GOV.UK

To put that into context, imagine a relatively straightforward development of 10 homes averaging 80m² each.

That's approximately 800m² of residential floorspace, before considering any chargeable communal areas.

At the Wokingham rate, that would give an illustrative levy of:

Previously developed land:800m² × £22.49 = £17,992

Non-previously developed land:800m² × £44.98 = £35,984

For a 20-home development averaging the same 80m²:

Previously developed land: approximately £35,984

Non-previously developed land: approximately £71,968

And at 30 homes:

Previously developed land: approximately £53,976

Non-previously developed land: approximately £107,952

These aren't quotes for individual projects — the actual calculation depends on the chargeable floorspace and the circumstances of the development — but they demonstrate the scale of the additional cost. GOV.UK

Why the 10-home threshold interests me

This is perhaps the part of the new levy that I think deserves the most consideration from the perspective of the SME developer. A developer delivering hundreds of homes has a very different financial model from someone bringing forward a 10, 15 or 20-home scheme.

For a smaller developer, an additional cost of £20,000, £40,000, £70,000 or more isn't necessarily something that can simply be absorbed.

It has to sit somewhere within the development appraisal.

And that's before we consider land acquisition, construction inflation, finance costs, professional fees, planning obligations, Community Infrastructure Levy, affordable housing requirements and the increasing number of technical and compliance requirements that come with residential development.

The Government itself recognised during the consultation process that SME developers can be disproportionately affected by development costs and operate on smaller margins. GOV.UK

That doesn't mean the levy shouldn't exist.

It does mean, in my view, that the cumulative effect of all these requirements needs to be understood when we talk about housing delivery.

Safety and viability aren't opposing objectives

I don't think this needs to be an argument between building safety and development viability.

We need both.

People buying or renting a home should be able to expect that the building has been designed and constructed to appropriate safety standards.

Equally, if the cost and complexity of delivering housing becomes too difficult for developers to make schemes work, there is a risk that projects simply don't progress.

As architects, we therefore have an important role to play much earlier in the process.

It's not enough to produce a design that looks good and satisfies the planning requirements.

We need to understand the whole development equation.

Can the building be constructed efficiently?

Does the core work?

Does the layout make commercial sense?

Are we designing efficiently within the new safety requirements?

What happens when the building crosses a particular height threshold?

What additional costs are coming into the project?

And, importantly, are we identifying these things early enough for the developer to make informed decisions?

To recap, the dates I would have in my diary for anyone involved in residential development, particularly around the Reading and Wokingham area:

30 September 2026

New second staircase provisions come into force for relevant new residential buildings at 18m+.

1 October 2026

The Building Safety Levy comes into operation for qualifying residential developments.

Neither change means development stops.

But both reinforce something I have increasingly found in my work: early design decisions have a much bigger financial impact than they used to.

The days when you could develop a concept, get planning permission and then work out the technical and financial implications later are becoming increasingly difficult.

For developers, architects, engineers and consultants, the earlier we understand the regulatory and commercial constraints, the more opportunity there is to design intelligently around them.

For me, that is the real conversation.

How do we continue to create safe, good-quality homes while making sure schemes remain deliverable?

That's a question I'm sure many developers will be asking over the coming months.