What Is the DBP Act? A Guide for Apartment Owners and Strata Managers
The Design and Building Practitioners Act (DBP Act) is NSW legislation that regulates who can design, document and certify building work. It requires registered practitioners to declare that their work complies with the National Construction Code (NCC) and relevant Australian Standards, creating a documented line of accountability that did not previously exist.
Why the DBP Act Was Introduced
The DBP Act followed high-profile building failures, including cracking at the Opal Tower and structural issues at Mascot Towers. These cases exposed a lack of accountability across the NSW construction industry, leaving owners with defective buildings and no clear party responsible for the defects.
The DBP Act addresses this by ensuring work is carried out by registered practitioners who carry professional indemnity insurance. If work is defective, there is now a documented trail back to the practitioner who approved it.
How the DBP Act Applies to Class 2 Buildings
Class 2 buildings, meaning residential apartment buildings where owners share common structural elements, sit at the centre of the DBP Act. This is where the impact of poor building practice is shared across multiple owners rather than a single household, making registered oversight essential.
Under the DBP Act, regulated building work on a Class 2 building predominantly includes structural work, waterproofing and fire safety systems. A registered design practitioner (engineer) must produce a compliant design, and a registered building practitioner (contractor) must construct to that design. This applies to new developments and to repairs on existing buildings alike, regardless of the building's age.
DBP Act Compliance and Waterproofing Membrane Repairs
When owners seek to upgrade or replace balcony tiles, doors, or balustrades, the scope of work often extends beyond the apparent repair or replacement. This is primarily due to the impact such works can have on the existing waterproofing membrane and the associated compliance requirements.
For example, the removal of balcony doors, tiles, or balustrades will commonly damage or compromise the underlying waterproofing membrane. Under the Design and Building Practitioners Act (DBPA), building practitioners are required to comply with the National Construction Code (NCC) and relevant Australian Standards when carrying out remediation works. Where the waterproofing membrane is disturbed, the Design Practitioner is generally unable to certify the works unless the waterproofing system is replaced and terminated in accordance with AS 4654.2.
To be effective, waterproofing membranes must remain continuous and terminate at appropriate, compliant locations. These terminations are typically achieved within drip grooves beneath slab edges, within wall cavities behind external masonry façades, and beneath the subsills of compliant doors or full-height windows.
Patch Repairs vs Certified Remediation
The DBPA promotes comprehensive remediation practices that address the underlying causes of building defects rather than simply treating visible symptoms. Prior to the introduction of these requirements, repairs were often limited to localised defects, resulting in ongoing water ingress issues elsewhere within the waterproofing system.
A patch repair may temporarily stop water penetration at one location, but it does not necessarily prevent moisture from migrating through adjacent defects, penetrations, or non-compliant terminations. By requiring affected systems to be brought into compliance, the DBPA aims to reduce recurring failures and improve long-term building performance.
This approach improves accountability among all parties and helps ensure remediation works perform as intended over their service life.
What This Means for Owners and Strata Managers
Work once treated as routine maintenance now needs to be scoped and certified by a registered design practitioner under the DBP Act. This adds a step and a higher up-front cost, but it ensures a documented compliance trail exists and protects the owners from future construction defects and unforeseen costs.
NBCE supports owners’ corporations and strata managers across NSW with DBP Act-compliant design, inspection and certification services. Contact us to discuss your next project.