The long‑signalled requirement for a secondary stair in new residential high‑rise has now taken effect, with planning and building control teams beginning to reflect the rule in current submissions. Housebuilders, build‑to‑rent operators and developers are moving quickly to test how the added core changes net area, unit mix and viability. Architects and fire engineers are reworking egress strategies and smoke control, while contractors assess programme impacts and resequencing around a larger or re‑positioned core. Local planning authorities are indicating that live applications may need revisions, though the handling of transitional schemes appears to vary by authority. Funders and insurers are watching closely, and some are said to be seeking evidence that designs align with the new position before releasing drawdowns. The shift lands at a time of heightened scrutiny over life safety in residential buildings and tighter gateways under the building safety regime.
TL;DR
/>
– The second stair requirement is now being applied to new residential high‑rise, with planning and building control starting to reference it.
– Design teams should expect core layouts, net‑to‑gross and smoke control strategies to change, with potential knock‑ons for unit numbers and mix.
– Contractors are reporting likely programme adjustments, procurement of stair components, and resequencing around reworked cores.
– Transitional handling for schemes already in the pipeline varies, so early dialogue with the authority and building control is essential.
What it means for UK residential high‑rise delivery
/> For design teams, the immediate task is to re‑site or enlarge the vertical core to accommodate a compliant second stair and associated fire‑rated structure. That typically triggers a cascade: revised lift and riser positions, fresh smoke ventilation strategies, and a check on structural grids, especially where long‑span slab solutions are in play. Most teams anticipate some net‑to‑gross pressure, so apartment layouts and mix may need rationalising to protect value while meeting egress and compartmentation requirements. MEP distribution is likely to be revisited as riser paths change, and façade coordination will need another pass where stair locations alter window and spandrel arrangements.
On the commercial side, viability models are being refreshed to reflect potential area losses and any uplift in construction allowances for additional structure, doorsets and fire protection. Employers’ Requirements may need amendments to capture the updated life‑safety strategy, while PCSA scopes are being expanded for re‑design, coordination and cost checks. Consultants advise early engagement with building control and the fire engineer to test interpretation points, particularly where sites are constrained and alternative arrangements could be considered within the rules. Where planning consents exist, teams are weighing minor‑material amendments against fresh submissions, factoring in committee cycles and consultation.
A plausible on‑the‑ground scenario is playing out on a city‑centre tower where enabling works are complete but the main contract has not been let. The client pauses to instruct a core redesign to incorporate a compliant second stair, accepting a modest reduction in net saleable area. The architect and structural engineer re‑coordinate the core, moving a riser bank and adjusting slab openings, while the fire engineer revises the smoke control approach. Planning officers signal that a targeted amendment is likely acceptable, subject to updated drawings and a short consultation. The contractor rebases preliminaries and resequences early floors to prioritise core works and maintain tower crane efficiency. Funders request confirmation that the redesign aligns with the live regulatory position before releasing the next tranche.
Timelines, procurement and the road ahead
/> Programme‑wise, the market expects a front‑loaded design effort and potential tender delays where documentation must be updated. Two‑stage procurements may become more attractive to clients who want early contractor input on buildability around larger cores and stair prefabrication. Supply chain capacity for precast and in‑situ stair flights, fire‑rated doorsets and smoke control kits could tighten if many schemes pivot at once, so buyers are exploring early orders and alternatives. Contracts will also need careful drafting around responsibility for redesign, gateway submissions and any resulting time and money, particularly on schemes that were at an advanced stage.
Finance and planning considerations will run in parallel. Planning authorities are signalling alignment with the new position, and many will expect clear statements on egress and life‑safety in design and access documents. S106 and affordable housing heads of terms may be revisited if unit numbers change, which has knock‑on effects for grant, valuation and delivery phasing. In the rental market, operators are considering whether amenity and back‑of‑house areas can be rationalised to offset area trade‑offs without diluting resident experience.
# What to watch next
/>
Key areas to keep in view as the market adjusts to the new rule:
– How transitional arrangements are applied to projects with consent or those already in procurement, and where local authorities set their cut‑off points.
– The extent to which fire‑engineered alternatives are considered within the regime on constrained sites.
– Supply chain responsiveness for stair systems, cores, smoke control and associated doorsets in the near term.
– Whether lenders and insurers tighten underwriting positions, influencing funding terms and sales strategies.
# Caveats
/> Details of scope, definitions and any transitional reliefs are still being interpreted on live schemes, and approaches may vary between authorities and building control bodies. Teams should rely on the latest formal guidance and project‑specific advice rather than assumptions drawn from other jobs. Some projects could see limited design change if they benefit from transitional provisions, but others may need more extensive rework depending on stage and approval status. None of this constitutes legal or technical advice.
The direction of travel points to second stairs becoming a baked‑in assumption for new residential towers, with design and procurement methods adjusting to make that the new normal. The key question is how quickly the industry can absorb the change without materially denting delivery volumes or scheme viability in tighter markets.
FAQ
/>
What does “second staircase” mean in this context?
It refers to a requirement for two independent protected escape stairs serving residential high‑rise buildings, forming part of an overall life‑safety strategy. The intent is to improve evacuation resilience and fire‑fighter access, working alongside compartmentation, smoke control and alarm systems. Exact technical provisions depend on the applicable regulations and guidance in force.
# Which projects are affected now that the rule is live?
/> The change is being applied to new residential high‑rise schemes moving through planning and building control, with transitional handling for in‑flight projects varying by authority. Teams with consents or tenders already in motion are being asked to engage early to confirm how their specific case will be treated. As always, the applicable scope turns on the definitions adopted in the current regime.
# How might designs change on typical towers?
/> Core layouts are likely to grow or be reconfigured to include a compliant second stair, which can affect lift positions, risers and smoke ventilation. Apartment layouts may be adjusted to recover efficiency, and structural grids may be tuned to accommodate revised openings. Façade and MEP coordination will usually need a fresh round to reflect the new core geometry.
# What could this mean for cost and programme?
/> Most teams expect some upfront redesign effort and potential tender or gateway delays as documentation is updated. There may be additional spend associated with stairs, fire doors, structure and coordination, offset where possible by design efficiencies. The overall impact will be scheme‑specific, influenced by constraints, procurement route and the stage at which changes are made.
# What should project teams do first?
/> Confirm the regulatory position with the planning authority and building control, and align the fire strategy with your design team. Re‑run area schedules, cost plans and programme to understand trade‑offs, and speak to suppliers early about stair systems and related components. Document any changes clearly in submissions to reduce approval risk and keep funders informed.
