Ministers have confirmed that new residential buildings over 18 metres in England will be expected to include a second staircase, with a firm cut-off falling in 2026. The move, long trailed by government and anticipated by many fire engineers, sets a clearer timeline for design teams and developers who have been holding schemes in abeyance. It affects both public and private housing pipelines, from build-to-rent and student blocks through to mixed-tenure schemes. The confirmation brings forward immediate decisions on redesign, re-consenting and procurement of revised cores and escape systems. Transitional arrangements are understood to exist, but the direction of travel is that single-stair designs will cease to be acceptable for new 18m-plus projects beyond the deadline. That puts pressure on programmes and viability appraisals in the coming months, particularly where layouts, net internal areas and unit mixes are tightly wound.
TL;DR
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– Second staircases will be required on new residential buildings above 18m in England, with a 2026 cut-off guiding compliance.
– Design teams should review layouts, egress strategies and plant locations now, and engage early with building control and fire engineers.
– Developers may need to revisit planning approvals, viability and phasing to accommodate a second core and associated systems.
– Contractors face resequencing risks and supply-chain adjustments for cores, stairs, smoke control and services.
What the 2026 cut-off means for schemes above 18 metres
/> For clients and consultants, the practical meaning of a 2026 cut-off is binary: either a scheme over 18 metres proceeds with two stairs in compliance with the post-deadline position, or it must demonstrate it qualifies under any transitional route before that point. In commercial terms, the second core typically requires space reallocation, potential loss of net saleable or lettable area, and rethinking of plant, risers and shafts. Fire and smoke control strategies—pressurisation, vents and lobbies—will need to be revalidated, as will evacuation modelling and lift provision. On constrained sites, a second core can also interact with façade design, daylighting calculations and structural grids, prompting knock-on revisions to apartment typologies and accessibility.
Local planning authorities are bracing for a rise in Section 73 applications and non-material amendments where previously consented schemes need additional core space or façade changes. Some projects may find they need a fresh application if massing, unit counts or external appearance shift materially. Building control bodies will expect to see updated fire statements and egress calculations that unambiguously reflect the two-stair approach. The earlier these issues are brought into pre-app and compliance conversations, the less exposure there is to rework late in the programme.
# Site scenario: how a redesign could play out
/> A mid-rise city-centre scheme over 18 metres is nearing tender, with a single stair designed under earlier assumptions. The client pauses to model a second staircase, discovering it compresses several one-bed units and requires relocation of a roof plant to maintain clearance above the cores. The architect adjusts the structural grid to avoid transfer elements, while the MEP team re-routes risers and revises smoke control to suit enlarged lobbies. The contractor flags lead times on precast stair flights and core formwork, reshuffling the programme to bring forward groundworks while the superstructure package is re-detailed. Planning officers indicate a Section 73 route is viable given minimal changes to height and massing, but request updated daylight and façade drawings before sign-off.
Design, cost and programme implications across the supply chain
/> Contractors are already reporting pressure on sequencing as core locations shift and stair elements move up the procurement agenda. Where offsite or slip-formed cores are specified, suppliers may need early engagement to confirm tolerances, lifting strategies and installation windows. Designers will be re-running egress models and recalibrating lobby sizes and door widths to align with the second stair, often triggering secondary changes across services zones, risers and ancillary spaces. Housebuilders and build-to-rent operators are rechecking standardised apartment stacks, with some moving to more symmetrical plans to accommodate twin cores without excessive corridor runs.
Cost plans are being revisited, not only for the additional stair but for consequential scope in partitions, doorsets, smoke control, lifts and structural works. Some schemes may claw back efficiency through simplified shafts or by rationalising apartment sizes; others may accept lower net-to-gross ratios to retain planning massing. Programme-wise, the risk sits in late-stage redesign: every month spent reworking cores can compress procurement and façade release dates, raising exposure to escalation and availability issues.
# Caveats
/> There is still uncertainty around exactly how transitional arrangements will be interpreted in borderline cases, including what constitutes “sufficient progress” before the deadline. The position in Scotland, Wales and Northern Ireland may differ, so cross-border portfolios should not assume a single UK-wide approach. Mixed-use schemes and conversions can raise edge cases on scope and measurement, and project teams will want documented advice from their fire engineer and building control body.
From policy to site: timelines, risk and capacity
/> The cut-off concentrates risk around approvals and technical assurance, areas that already face limited capacity. Building control teams and fire engineers are likely to see surges in workload as schemes are redesigned and re-submitted, increasing the value of early, well-evidenced proposals. Land deals and options linked to unit counts or gross development value may need re-opening if layouts move materially, and lenders will be looking for clear statements on compliance pathways to mitigate deliverability concerns. For public programmes, the impact on grant conditions and tenure mixes may require dialogue with funding bodies to avoid delays.
# What to watch next
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– Clarification on how transitional arrangements will be applied in practice for schemes straddling the deadline.
– Any additional guidance on acceptable design solutions for constrained footprints and complex mixed-use layouts.
– Signals from local planning authorities about preferred routes for amending existing consents to add a second stair.
– Market response in tender prices and lead times for core systems, stairs, doors and smoke control components.
The direction of travel is now set: two-stair solutions will become the default for new 18m-plus residential blocks, and the market is pivoting to make that workable at scale. The key question is whether design, approvals and supply capacity can align quickly enough to avoid a dip in starts as the 2026 deadline draws near.
FAQ
# What does the 2026 cut-off actually require?
/> It marks the point after which new residential buildings over 18 metres in England are expected to include a second staircase as part of their fire safety strategy. Transitional routes may exist for schemes that have progressed sufficiently before the deadline, but the policy intent is to move to two-stair designs. Project teams should verify the position with their building control body and fire engineer.
# Does this apply across the whole UK?
/> The confirmation relates to policy in England. The devolved administrations set their own building standards and timing, so requirements may differ in Scotland, Wales and Northern Ireland. Portfolios spanning multiple nations should take local advice before locking designs.
# What happens to schemes already in planning or on site?
/> Industry briefings suggest transitional arrangements are intended to prevent stranded projects, particularly where work is already advanced. Whether a specific scheme qualifies will depend on its approvals status and progress and will need agreement with the relevant authorities. Many teams are choosing to redesign now to avoid later uncertainty.
# How might a second staircase change building design?
/> A second core typically rebalances floorplates, affects corridor lengths and lobby sizes, and can influence riser, lift and smoke control strategies. Structural grids and plant locations may need to shift to keep efficient spans and maintain headroom. The impact varies by site constraints and building typology.
# What should project teams do now?
/> Start a targeted review of schemes over 18 metres, prioritising those near tender or construction, and engage early with building control and the fire engineer. Map the planning route for any material amendments, refresh egress modelling, and bring core systems and stairs forward in procurement. Keep funders and occupiers informed where layouts or unit numbers may change.
