PSST! Did you hear the one about the simple little house that had specification clauses for six cladding types? Unfortunately, none of them were the one actually used on the building.
Drawings found wanting
One of the biggest bugbears when trying to get a building consent can be requests for information (RFIs). This is both for the building consent authority (BCA) staff member writing them and the consent applicant such as the designer and builder receiving them.
Before any designers jump up and down, the BRANZ construction documentation survey of 53 sets of drawings found:
- 40% were lacking details
- 15% lacked clarity and were not job specific
- 30% referred to other documents for details
- 50% had inconsistent scales
- 59% did not clearly identify materials and finishes.
Reducing the risk of RFIs
The potential for an RFI should be reduced where consent documentation:
- includes a completed and signed application form
- includes a recent certificate of title
- is clear and easy to read
- has spaces correctly labelled
- is project specific
- identifies restricted building work
- complies with the required information as identified by the BCA
- identifies site coverage, distance to boundaries, relative levels to a recognised datum of floors and finished ground and more
- includes details of critical aspects of construction
- is consistent and coordinated across all professions, such as designer, architect, engineer and fire engineer
- identifies the compliance paths being used
- references the means of compliance – Acceptable Solution or alternative method with supporting evidence as to Code compliance
- is supported by relevant information
- includes all required producer statements
- has the required certificate of design work
- has the engineer’s design features report where specific engineering design is utilised
- has been peer-reviewed before submission.
What should be in the drawings
On its website, MBIE states that, as a minimum, all drawings submitted for consent should contain:
- a drawing number and title
- the designer’s and owner’s name and the job address
- version control dating.
Depending on the project, your application might need to include:
- site plan
- location plan
- foundation plan
- floor plan
- roof framing plan
- exterior elevations
- construction details
- door and window schedule
- plumbing layout or schematic plan
- wet area details including waterproofing as necessary
- electrical plan
- how clause H1 Energy efficiency is being complied with and the levels of insulation provided.
Minimum detailing should cover:
- structural elements, junctions and fixings
- window and door head, sill and jamb
- penetrations through exterior walls and roofs
- fire separation junction and penetration details
- cladding junctions (horizontal and vertical)
- wall and roof junctions
- expansion and movement joints
- bottom plate and cladding overhang
- weatherproofing details including the difficult ones
- soffit and parapet details
- stairs showing rise, going, pitch and handrails
- damp-proofing and tanking (if part of the project), cross-sections and details
- deck balustrades and handrails, heights, layouts and fixings
- deck or pergola connections to main structure
- retaining wall details (if part of the project).
Information on what constitutes a good set of documents and the requirements for a building consent application are available from:
- BRANZ Bulletin 505 Acceptable plans and specifications
- BRANZ Renovate, see www.renovate.org.nz, then Regulation and compliance
- MBIE website at www.building.govt.nz/projects-and-consents/apply-for-building-consent/.