From 30 September 2026, all new residential buildings over 18 metres must be designed and built with two protected staircases. The requirement comes from amendments to Approved Document B, the government’s fire safety guidance, published in March 2024 as part of the response to Grenfell.
Most of the coverage so far has focused on design and cost. Less has been said about what happens to your insurance when a scheme has to be redrawn.
That gap matters. A second staircase changes the construction value, the build programme, the fire strategy and the structural design. Each of those sits behind a policy schedule somewhere. Contractors’ all risks, structural warranty and professional indemnity cover were all priced against a design that may no longer exist.
This article looks at the second staircase rule from the insurance and liability side. What triggers a policy review, who carries the cost of a redesign under a JCT contract, and what developers with schemes above 18 metres should be doing this month.
What the Second Staircase Rule Actually Requires
The rule applies to new residential buildings in England with a top occupied storey more than 18 metres above ground level. That is roughly six storeys, though it depends on floor-to-floor heights.
Three points catch people out.
- The 18 metres is measured to the floor of the highest occupied storey, not to the roof or parapet.
- Interlocked stairs count as a single staircase under the revised guidance, so a scissor stair does not satisfy the requirement.
- A second stair is also needed where flats are not separated from the common stair by a protected lobby, or where travel distances exceed 7.5 metres in one direction or 30 metres in more than one.
The 18 metre threshold was chosen to match the definition of a higher-risk building under the Building Safety Act 2022. Any building caught by the second staircase rule is also caught by the Building Safety Regulator’s three gateway approvals process.
England is catching up here rather than breaking new ground. Scotland has had an 18 metre limit for years, and similar thresholds apply across much of Europe and North America.
The Transitional Rule and Why 30 March 2028 Is the Real Deadline
Schemes already in the pipeline can rely on the older single-stair guidance, but only if they pass a two-part test.
First, a building notice, initial notice or full plans application must reach the relevant building control authority before 30 September 2026.
Second, the works must be “sufficiently progressed” within 18 months of that date. That means by 30 March 2028.
“Sufficiently progressed” has a specific meaning borrowed from the higher-risk building transitional rules. It means the pouring of concrete for permanent foundations, or the permanent placement of piling, has started. Site clearance, hoarding and enabling works do not count.
Two misunderstandings are common.
Planning permission does not protect you. Only the building control route counts. A scheme with consent but no building control application will fall under the new rules.
Getting approval is not enough either. If a site acquisition stalls, funding slips or a planning condition drags on, and foundations are not in the ground by 30 March 2028, the transitional protection is lost. The scheme goes back for redesign.
The scale of this is not small. Forsters reported that around 38,000 homes in London alone had been delayed by uncertainty around the requirement. Industry tracker Glenigan put the number of affected London units at roughly 23,000 at one point. Many of those schemes are now approaching their transitional cliff edge.
Contractors’ All Risks: Why a Redesign Rewrites the Policy
A contractors all risk policy covers physical loss or damage to the works, materials and temporary works during the construction period. It is priced on three things: the value of the works, the nature of the works, and how long they take.
A second staircase moves all three.
Adding a second core changes the construction value. It usually extends the programme. It alters the specification, bringing more fire-stopping, more compartmentation and a different structural frame. A policy written for the original scheme may no longer describe the project being built.
Practical points to raise with your broker:
- Revised sum insured based on the new construction value, not the original tender figure
- Extended policy period covering the longer build programme
- Cover for delay in start-up if funding drawdown depends on completion dates
- Gateway 2 approval delays, which can leave a site dormant while a policy runs
- Whether the joint names arrangement still names the correct parties
Non-disclosure is the risk here. If the design changes materially and the insurer is not told, a claim can be reduced or refused. Speak to your broker before the redesign is instructed, not once the revised drawings are issued.
Structural Warranty and Latent Defects Cover Need a Fresh Technical Audit
Structural warranty insurance runs for 10 or 12 years after completion and protects against structural defects that appear later. Most mortgage lenders require it, so no warranty usually means no sales.
Warranty providers do not simply issue a policy. They appoint technical auditors who review the design, the structural calculations and the specification before cover is confirmed, and they inspect during the build.
A second staircase changes the loadings, the frame, the fire strategy and the layout. That audit has to be rerun against the revised design. Cover on the old drawings does not transfer across.
There is a cost implication too. Latent defects cover has historically been priced in the region of 1.3% to 1.7% of rebuilding cost, according to Designing Buildings. On a scheme where the redesign pushes the construction value up, the warranty premium moves with it.
Timing is the bigger risk. Warranty applications on higher-risk buildings take time, and the audit sequence needs to run alongside the Building Safety Regulator’s gateway process. Starting late can hold up handover and sales completions.
Professional Indemnity and the Design Liability Shift
The second staircase rule creates an unusual situation. On a redesigned scheme, two designs sit on the risk register at once.
The original single-stair scheme was designed, checked and signed off by a project team. That work does not disappear. Claims can be brought years later, so run-off professional indemnity cover on the abandoned design still needs to be in place.
The redesign then brings a second set of design decisions, often produced at speed under deadline pressure. Rushed design work is exactly what PI underwriters worry about.
JCT DB 2024, published in April 2024, raised the contractor’s design standard. Under the 2016 form, the benchmark was that of an architect or other professional designer. The 2024 form raises it to a qualified and experienced architect or other appropriate professional designer. Contractors taking on a stair redesign are being held to a higher bar than before.
Marsh has also flagged a newer exposure. Mismanagement of the golden thread of information and the mandatory occurrence reporting system could produce professional indemnity claims even where no design error occurred. On a higher-risk building, the paperwork is part of the risk.
JCT Contracts: Is the Redesign a Change or Your Problem?
This is where money is won and lost.
Under JCT Design and Build, clause 5.1 defines a change as an alteration to the Employer’s Requirements that changes the design, quantity or quality of the works. A client instruction to add a second staircase to comply with a statutory requirement will usually be a change, and therefore valued as a variation with an entitlement to time and cost.
Two things can undermine that position.
Bespoke amendments are increasingly drafted so that any errors, inconsistencies or divergences in the Employer’s Requirements are deemed to be contractor risk. Where that wording appears, the contractor may find the redesign treated as design development rather than a change.
The JCT forms also contain no drafting for the Building Safety Act gateway regime. Gateway 2 is a hard stop. Nothing can start on site until the Building Safety Regulator approves. JCT has acknowledged it made no special provisions for gateway delays, so parties are dealing with it through bespoke schedules of amendments. Who carries the delay risk when the regulator is slow is a matter of drafting, not standard terms.
That question is already in front of the courts. The Technology and Construction Court dealt with gateway approval delays in GS Woodland Court GP 1 Ltd v RGCM Ltd [2026] EWHC 351 (TCC), and the point is likely to recur.
A contract that has been amended for gateway risk and a policy that has not been reviewed since 2024 are a poor match. Both need looking at together.
Your Checklist
If you have residential schemes above 18 metres, five things need doing now.
- Audit the pipeline. Identify every scheme over 18 metres without building control approval. Those either need an application in before 30 September 2026 or a redesign.
- Stress-test the 2028 date. For schemes relying on transitional protection, work backwards from 30 March 2028 and check that foundations or piling will realistically be underway.
- Review contract terms. Check whether your amendments treat a statutory redesign as a change, and who carries gateway delay risk.
- Re-broker the cover. CAR, warranty and PI policies all need reviewing against the revised design, revised value and revised programme.
- Sequence the warranty audit early. Technical audits and gateway submissions run in parallel and both take time.
Why the Redesign Conversation Starts With Your Broker
The second staircase rule is being treated as a design problem. It is also a risk transfer problem, and the two are not on the same timetable.
Design teams can redraw a core in weeks. Reissuing a contractors all risk policy, rerunning a warranty technical audit and confirming professional indemnity cover on two separate design versions takes longer, and each one depends on information the others produce.
Schemes that fall out of transitional protection after 30 March 2028 will face all of this at once, on a site that is already sitting idle and costing money.
If you hold property developers insurance on a scheme above 18 metres, the sensible move is to map the insurance consequences before the redesign is instructed rather than after. Our team has been placing construction cover for developers and contractors for over 30 years, and we read the contract before we place the policy.
Talk to us and get a quote for your revised scheme.