Building Safety Act Gateway 2 cost impact on residential HRBs, 2026
What design, programme and construction cost lines the Gateway 2 approval regime is adding to residential higher-risk buildings.
Gateway 2 is the first statutory approval checkpoint for higher-risk buildings. It is adding 3 to 8% to total build cost on eligible residential projects, plus 8 to 12 weeks of pre-start programme, and is reshaping how QSs cost-plan these jobs.
Sources: Building Safety Act 2022, BSR operational guidance, RICS and CIOB market commentary. Live labour cost backdrop: ONS Labour Cost Index for construction. Latest: N/A.
A higher-risk building (HRB) is defined under the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 as a building that is 18 metres or taller, or has 7 or more storeys, and contains at least 2 residential units. Gateway 2 sits between planning and construction under the Building Safety Act 2022, and no in-scope project can start on site without Building Safety Regulator (BSR) approval of the design.
Which projects this applies to
- 18 metres or more above ground level.
- 7 or more storeys.
- Contains at least 2 residential units.
- In-scope from planning through to handover.
Mid-rise residential developers are increasingly running buildings just under the threshold (typically 17.5m, 6 storeys) specifically to avoid the regime. That is a strategic choice with its own cost and design consequences, and worth modelling alongside the in-scope option on any marginal scheme.
Source: Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023. Always confirm against the current guidance at gov.uk/guidance/higher-risk-buildings-regulator.
The cost lines that change
| Cost area | Change | Typical uplift |
|---|---|---|
| Design fees | Principal Designer competence evidence, Gateway 2 package, fire and structural safety case | +20 to +40% on design fee |
| BSR approval fee | Building Safety Regulator statutory fee, scales with floor area | +£30,000 to £150,000 per building |
| Programme | 8 to 12 week BSR review, longer if deficiencies | +£50,000 to £300,000 of preliminaries |
| Competence evidence | Compiling contractor and designer competence records | +£10,000 to £40,000 of management time |
| Insurance | PI and latent defects repricing | +5 to +15% on cover cost |
| Golden thread | Information management system for regulated info | +£20,000 to £60,000 set-up plus ongoing |
Ranges are based on market commentary from RICS, CIOB, and BSR guidance at time of writing. Actual figures vary substantially by project complexity and by how well the design team has prepared the submission.
What Gateway 2 actually checks
The BSR reviews the design package for compliance with Building Regulations with particular weight on fire and structural performance. Four specific items sit at the top of the review list:
- Design package compliance with Building Regulations, with fire and structural performance scrutinised hardest.
- Competence evidence for the Principal Designer and Principal Contractor.
- The proposed construction control plan (how changes will be managed during build).
- The golden thread information management approach.
Source: Building Safety Act 2022, Part 3; BSR operational guidance.
Timeline implications for cost planning
ONS Labour Cost Index for construction. Base: 2015 = 100. The plot lines show when the Building Safety Act received Royal Assent and when the full Gateway regime became live for in-scope HRBs.
Assume 12 weeks from submission to approval as a realistic baseline. BSR statistics through 2024 and into 2025 showed average review times lengthening, with complex submissions running 16 to 20 weeks. Price the preliminaries on the longer scenario, not the statutory minimum.
Minor design changes mid-construction need change-control approval. Major changes require resubmission to Gateway 2, which can stop work on site. Cost planners should build in a change-management contingency of 2 to 4% of contract value on HRB projects that is ring-fenced for this risk specifically, rather than folding it into the general contingency where it competes with scope risk and prelims overrun.
How QSs should adjust their cost plans
- Add a dedicated Gateway 2 line in the cost plan, not just spread the uplift across existing headings.
- Price design fees on the high side until the practice has a completed HRB in its track record.
- Build preliminaries at 12 to 16 weeks of pre-start for Gateway 2, on top of the standard mobilisation period.
- Carry a separate change-control contingency of 2 to 4% on top of the base contingency.
- Flag competence evidence compilation as a distinct workstream with its own cost.
- Price PI cover uplift into fee proposals; do not absorb it.
The design-and-build contractor question
Some developers are moving away from pure design-and-build for HRBs because the Principal Designer duty under Gateway 2 sits uncomfortably with contractor-led design. A common alternative is a two-stage procurement where the design is completed to Gateway 2 approval under an independent Principal Designer, then handed to a contractor for construction. QSs should expect this procurement shift to continue and price accordingly (typically +1 to +2% on overall cost versus pre-BSA D&B baseline, traded off against reduced change-control friction later).
What is less of a problem than first feared
The industry feared Gateway 2 would add 15% or more to HRB costs. In practice, on well-run projects with experienced Principal Designers, the total uplift is sitting at the lower end of the 3 to 8% range cited above. The bigger risk is programme, not direct cost. Badly prepared Gateway 2 submissions that bounce back from the BSR lose weeks, and those weeks hit the preliminaries line hardest, compounded by any labour cost drift during the wait. See the companion guide on fixed-price versus cost-plus contracts for how this reshapes the procurement conversation.
Cost ranges in this article are industry estimates at time of writing, synthesised from RICS and CIOB commentary and from BSR published guidance. The regime is still maturing; numbers will stabilise as more HRB approvals complete. Always confirm with the Building Safety Regulator published guidance (gov.uk/guidance/higher-risk-buildings-regulator) for current statutory requirements. For the live labour figure the preliminaries inflation rests on, see the Cost Tracker.