The Building Safety (Wales) Bill

The Building Safety (Wales) Bill was passed by the Senedd in March 2026. Following a four week statutory period in which various devolution/legislative competence questions can be raised by the UK government, the Bill will go forward to Royal Assent (it is assumed this will occur in April 2026).

The Welsh government has previously said they plan for the Bill/Act to be implemented from April 2027 as various pieces of secondary legislation will be needed and the government has promised guidance to assist industry and residents transition to the new regime.  Similarly, it is likely that more detail about the Welsh regime will be set out in regulations and government guidance over the coming months.

This note sets out a high level overview of our understanding of the key differences between the English and Welsh regimes.  It is limited to the occupational phase of the building lifecycle, and does not address the construction or development phase.  These phases are not dealt with in the Bill and are instead the subject of secondary legislation which takes effect from 1 July 2026.  Our Construction team has written about this on LinkedIn here.

The table below summarises some of the key differences the notes following it provide some more detail.

Summary table

Issue	England	Wales
Buildings	“Higher risk building” (HRB): a building of at least 18m or 7 storeys in height containing two or more residential units	“Regulated building”: all buildings containing 2 or more residential units regardless of height Categories of regulated building: Category 1 – a regulated building of 18m/7 storeys or more Category 2 – a regulated building of 11m/5 storeys (up to but not including 18m/7 storeys) Category 3 – a regulated building under 11 metres in height or with less than five storeys
Exceptions	Buildings consisting entirely of: a hotel secure residential institution military barracks/MOD living accommodation	Buildings used solely as: armed forces accommodation secure residential accommodation a hospital a care home a school
Registration	HRBs must be registered with the Building Safety Regulator before they can be occupied	Category 1 and 2 buildings will both need to be registered with the building safety authority (the local authority for that area)
“Accountable Person”	An Accountable Person is (in broad terms) the person who owns or has a repairing obligation under a lease for any common parts in the HRB. Where there is only one Accountable Person for the HRB, that person will also be the Principal Accountable Person. Where there is more than one, the Principal Accountable Person is (in broad terms) the person with ownership or repairing obligations in the structure and exterior of the HRB.	Each regulated building, regardless of height, will have an accountable person, and principal accountable person who will be responsible for the management and assessment of structural and or fire safety risks depending on which category the building is in. The definitions of Accountable Person and Principal Accountable Person are similar but not identical to the English regime. For example: any person under a contractual obligation to provide services relating to repair, maintenance or safety of part of a regulated building (e.g. a managing agent) may be treated as being an AP for that part of the building.  This is not the case in England. The definition of AP includes any person who has any degree of control over part of the building.  Further detail on this may follow in regulations
Regulatory responsibilities for AP/PAP	Wide ranging specific responsibilities with the overarching aim of assessing and managing building safety risk i.e. the risk to the safety of people in or about the building from spread of fire or structural failure of the HRB.  Specific responsibilities include: Preparation of safety case and safety case report Registering the HRB before occupation Maintaining the “golden thread of information” about the building and providing information and documents to residents, the Building Safety Regulator and others in various circumstances engagement strategy and complaints procedures Apply for a building assessment certificate from the Building Safety Regulator when directed to do so	The responsibilities vary depending on the category of the regulated building. Category 1 buildings are subject to very similar requirements to HRBs in England. Category 2 buildings are more limited (for example structural assessments are not required for these buildings, but are for Category 1). Category 3 buildings are subject to yet more limited obligations, mainly focused on fire risk assessments. All regulated buildings will be subject to a requirement to maintain the golden thread of information.
Enforcement/ regulator	Centralised – the Building Safety Regulator	Decentralised – individual local authorities

Key difference – categories of building

There are several key differences between the English regime under the BSA 2022 and the Welsh approach under the Bill. In Wales, some version of a regulatory regime will apply to all buildings containing 2 or more residential units regardless of height (referred to in the Bill as “regulated buildings”). In England, the enhanced regulatory regime applies only to higher risk buildings (i.e. 18m or 7 storeys or more in height with two or more residential units)

Regulated buildings in Wales will be split into 3 categories determined by height and the number of storeys contained within the building.  Regulations are likely to be required to set out how height/no of storeys is to be determined – as was the case in England.

There are sliding scales of regulation for each category, with category 1 being the tallest and most highly regulated and the Welsh government’s intention is that the April 2027 implementation will start with these “Category 1” buildings:

• Category 1 – a regulated building of 18m/7 storeys or more (i.e. the same height threshold for what, in England, would be called a “higher risk building”);
• Category 2 – a regulated building of 11m/5 storeys (up to but not including 18m/7 storeys); and
• Category 3 – a regulated building under 11 metres in height or with less than five storeys

Category 1 and 2 buildings will both need to be registered with the building safety authority (which in Wales will be the local authority rather than a centralised Building Safety Regulator as in England).

Key difference – Accountable Person/Principal Accountable Person for all regulated buildings

It appears from the Bill that each regulated building, regardless of height, will have an accountable person, and principal accountable person who will be responsible for the management and assessment of structural and/or fire safety risks depending on which category the building is in.  An overview summary of obligations by building category is set out below:

The Bill’s terminology refers to management and assessment of “fire safety risk” and “structural safety risk”.  In the BSA, “building safety risk” is risk is a defined term which encompasses risk from spread of fire or structural failure.  The Welsh terminology is very similar but not an exact mirror of the BSA wording, so there may be additional nuances in Welsh secondary legislation setting out further detail on how such risks should be managed and assessed.

Category 1 and 2 buildings will be subject to both fire safety and structural safety duties.  Category 3 buildings and some HMOs will be subject only to fire safety duties.

The role of AP/PAP has existed in England since 2022 under the BSA, but only applies to higher risk buildings (i.e. buildings which would be in Category 1 in Wales).

The definitions of AP and PAP in the Bill are very similar to those in England but are not completely identical, which may make it slightly more difficult to navigate the regime across both jurisdictions.
For example, in the BSA, where there is more than one AP in a building, the PAP will be the person who has the ownership or repairing obligation for the structure and exterior of the building.  The Welsh Bill uses different wording, referring to the “external structure” which it defines as the foundations, external walls and roof of the building, subject to certain exclusions.  How this subtle difference in terminology will play out in practical terms remains to be seen.

There is an additional nuance which is that the Bill provides that any person under a contractual obligation to provide services relating to repair, maintenance or safety of part of a regulated building (e.g. a managing agent) may also treated as being an AP for that part of the building.  This is not the case in England.

In summary

Wales

• Broader scope: covers all multi occupied residential buildings with two or more units.
• Wider definition of AP and AP/PAP required for all regulated buildings.
• Registration required for lower rise buildings than in England
• Golden Thread applies universally.
• Local authority-led regulatory model, rather than a central regulator.

England

• Regulatory regime targeted at higher risk buildings.
• Narrower AP definition and AP/PAP only for HRBs.
• Golden Thread and registration limited to HRBs.
• Centralised Building Safety Regulator.