What qualifies as an HRB

A building is a high-risk building under the Building Safety Act 2022 if it meets all three criteria:

• At least 18 metres in height measured from ground level to the top floor surface, or at least 7 storeys.
• Contains at least 2 residential units at any point.
• Is in England (Scotland, Wales and Northern Ireland have their own regimes).

How height is measured

Height is measured from external ground level to the top of the top occupied storey. Excluded:

• Plant rooms and machinery above the top occupied storey.
• Single-storey decorative features (parapets, lift overruns).

Counting storeys

A storey is counted if it is at least 30 cm tall. Excluded:

• Basements that do not have any external access.
• Plant rooms.

Mixed-use buildings

A building with residential and commercial floors qualifies if at least 2 of the residential floors fall under the height or storey criteria. The commercial part of the building does not change the calculation.

Borderline cases

Buildings close to either threshold should be checked by a building surveyor. The Building Safety Regulator publishes guidance and you can submit borderline cases for confirmation.

Edge cases

Marking a site as HRB in PropLink

1. Open the site.
2. Click Edit.
3. Tick Is HRB.
4. Enter the building height and number of residential storeys.
5. Enter the Building Safety Regulator registration reference (assigned when you register).
6. Enter the registration date.
7. Save.

The site appears in the HRB module and the safety case section becomes available.

Mixed estates

For an estate with one HRB and several non-HRB blocks, mark the HRB site individually. Other sites continue without HRB obligations.