Wales has fixed 1 July 2026 as the go‑live date for the next block of Building Safety Act measures. The Welsh Statutory Instrument was made on 12 December 2025 by Rebecca Evans MS and brings key Part 3 powers of the 2022 Act into force for Wales, according to legislation.gov.uk (SI 2025/1368).

For developers, contractors and building control teams, the headline changes are practical. Compliance and stop notices (section 38), a revamped offence for breach of building regulations (section 39), automatic lapses of approvals and notices (section 36), and a fall‑back route for Welsh Ministers to determine certain higher‑risk building applications if deadlines are missed (section 37) all start applying in Wales on that date. Default powers enabling Welsh Ministers to transfer local authority building control functions in defined failure cases (section 45) also switch on.

Compliance and stop notices will matter day‑to‑day. Local authority building control will be able to direct remedial steps through a compliance notice or require specified work to cease via a stop notice where there is, or would be, a contravention. The Act lets building regulations set the format and service of notices and requires reasonable notification to others affected. In short: expect clearer paperwork and firmer timelines for putting defects right.

Appeals exist but don’t remove urgency. A compliance notice is paused while an appeal runs, but a stop notice may continue to bite unless a court or tribunal orders otherwise. Site managers will want pre‑agreed playbooks for partial shutdowns, sequencing around safety‑critical work, and evidencing prompt remedial action. That reduces downtime if disputes arise.

Penalties for breaches sharpen materially. Section 39 provides for prosecution on indictment with a potential custodial term of up to two years and fines; it also extends the window for local authorities to require alteration or removal of non‑compliant work from 12 months to 10 years. Record‑keeping, photographic evidence and a clean audit trail from design through handover now carry real value if challenged later.

Programmes will need re‑baselining around the new three‑year rule. From 1 July 2026, building control approvals, initial notices and related plans certificates will lapse automatically if work has not commenced within three years of the relevant application or acceptance date. On multi‑plot schemes, commencement must be evidenced for each building, so phasing plans and plot start certificates should be aligned to avoid sections of a site losing approval mid‑delivery.

There is also a service‑level backstop for higher‑risk building cases. If a building control authority does not determine prescribed applications within set timescales-and no extension has been agreed-the applicant can ask Welsh Ministers to decide the original application (section 37). That creates a clear incentive to track statutory clocks and resource complex submissions properly from day one.

Governance pressure rises on local authorities too. Section 45 updates ‘default powers’, allowing Welsh Ministers to transfer specified building control functions where performance risks public safety. This is a rare step, but the signal is unmistakable: leadership teams should invest in training, quality assurance and caseload management before the 1 July start.

What should businesses do between now and 30 June 2026? First, map projects against the three‑year commencement rule and document ‘start on site’ criteria that your building control body will accept. Second, refresh contracts and method statements so stop‑notice contingencies-temporary works, re‑sequencing, cost ownership-are explicit. Third, reinforce design assurance and site inspection routines so potential compliance issues are caught before they escalate to formal notices.

Cross‑border teams should note the Welsh pathway sits alongside earlier Welsh commencement regulations from 2023 and 2024 on dutyholders, competence and the registered profession. Approved Inspectors have been replaced by Registered Building Control Approvers and Registered Building Inspectors under Wales‑specific regulations, with Welsh Government circulars and charging schemes already in place. Those frameworks remain the baseline; 1 July 2026 adds sharper enforcement and time‑limit rules rather than starting from scratch.

For transparency: the commencement instrument is published on legislation.gov.uk as The Building Safety Act 2022 (Commencement No. 6) (Wales) Regulations 2025. The underlying provisions referenced above are sections 36, 37, 38, 39 and 45 of the Building Safety Act 2022, and related amendments in Schedule 5 to the Act, as shown on legislation.gov.uk and prior Welsh commencement regulations. Always check project‑specific transitional provisions with your building control body before acting.