Construction Certificate

Specifications

Many design decisions and building details cannot be easily put into plans/drawings and therefore rely on a written text document to be described.

The purpose of a specification is to describe the standard to which a building is to be constructed, in terms of structural, operational, and aesthetic aspects.

The building specification should include but not be limited to:

• reference to the plans
• a description of construction materials for the walls (internal/external), floors, windows and roof including linings
• the relevant standards to which the following building components are to be constructed:
  • footings (structural and geotechnical standards),
  • timber framing,
  • site drainage,
  • building work associated with the installation of oil or solid fuel heating,
  • appliances,
  • termite control,
  • fire safety measures (fire resistance levels and essential services),
  • wet areas,
  • lighting and ventilation,
  • sound transmission class rating,
  • stair construction,
  • balustrades and the like
• evidence of any accredited components, process or designs to be relied upon, where relevant
• site preparation
• finishes
• Any matters required by the BASIX Certificate(s) to be shown on the plans or specifications that is not easily shown on the plans.

Plans

Plans must be specific to the building and cover the entire scope of the building work the application is for.

Plans must be drawn to suitable scale, be fully dimensioned and include, but not be limited to:

• A title block, drawing number and revision, date of the drawing, and details of who prepared the drawing, and the project address and lot details.
• A key for abbreviations, colouring and hatchings and a north point.

The types of plans submitted with a Construction Certificate application should include:

1. A site plan, showing the location of the proposed building, setbacks from boundaries, levels of adjacent ground, existing buildings on site and other site features such as easements, and fire source features.
2. Floor plans for each floor of the building, showing all building elements and detailed layouts at a suitable scale, which should include:
   • Reduced levels and proposed finished levels.
   • The intended use of each room.
   • Dimensions of rooms.
   • Dimensions of walls and structural elements.
   • Internal and external wall construction, including details of any sound insulation, fire resistance or the like.
   • Locations of door and window openings.
   • Floor coverings.
   • Reflected ceiling layout.
   • Layouts or rooms within the building and location of fixtures.
   • Locations of services.
   • Details of any performance solutions as relevant
3. Architectural Elevations of the proposed building, showing the relevant floor levels and heights, design, finishes and materials, which should include:
   • Dimensioned heights, including the overall height.
   • Proposed external materials.
   • Proposed finished floor and ceiling levels.
   • Floor to floor and floor to ceiling heights.
   • Location and sizes of window and door openings, balconies another external features.
   • Details of any performance solution as relevant.
4. Architectural Sections of the proposed building of at least two intersecting sections showing building elements and construction methods, which should include:
   • Sections of ramps and other elements with gradients and stairways.
   • Finished floor and ceiling levels.
   • Floor to ceiling heights.
   • Wall, window and door heights.
   • Thresholds and set downs.
   • Structural supports.
   • Building services and equipment.
   • All relevant vertical and horizontal building elements and their relationship to the building.
5. Architectural Details showing building elements and construction methods, which should include:
   • Details of junctions and interfaces between and within major building elements.
   • Details of key areas of the building such as a glass curtain wall interface with the floor slab.
   • Details of penetrations and proposed protections methods.
   • Methods of weatherproofing and attaching building elements.
   • Waterproofing details.
   • Tanking and damp-proofing details.
   • Wall details such as for fire resistance and sound insulation.
   • Access ramp, landing, threshold details.
   • Provision for fire safety and fire resistance, showing which elements are fire resisting, the proposed level of fire resistance, and any fire compartmentation. Ideally plans should be colour coded differentiating all the fire-resisting elements and clearly identifying fire compartmentation and bounding construction for the building.
6. Other design and construction drawings such as:
   • Structural designs and plans
   • Hydraulic services design and plans.
   • Mechanical services design and plans.
   • Electrical design plans.
   • Fire safety services designs and plans.
   • Lift services design and plans

Boundary Surveys

Council Building Surveyors will require a boundary survey (from a registered land surveyor) in the following situations:

• For Class 1 and 10 development:
  • Where the gap between a building (or part) and a boundary is relied on for fire separation and the gap to be provided is less than 1000mm OVER the minimum distance required by the Deemed-To-Satisfy provisions of the Building Code (usually 900mm, for a total of 1.9m needed to avoid the need for a survey).
  • In other cases, where the gap between a boundary and a building (or part) is less than 1000mm.
• For other classes of development, or buildings/structures of an industrial or infrastructure nature, where the building or structure (or part) is less than 6000mm from a boundary.
• In any instance where there is doubt as to the location of the boundary.

These guidelines have been in place since January 2021.

 Geotechnical Reports and Soil Assessments

In recognition of the consistent soil type in city of Broken Hill which typically classifies as M-D (in accordance with AS2870-2011), the following guide applies.

• For all new dwellings and additions over 50m², a full soil report from a suitably qualified and experienced geotechnical engineer will be required.
• For additions of up to 50m² to existing buildings, the following applies:
  • In accordance with the BCA Volume 2 clause 3.2.5.2 footing and slabs may be similar to existing footing and slab on the site.
  • Where a soil report is not provided applicants will be required to submit a “Soil Assessment” containing the following:
    • Provided details of the existing dwellings footings and slab.
    • Show how the performance of the existing building has been satisfactory ie minimal defects evident.
    • Provide a description of the soil in the area of the additions and include a photo.
    • Provide a statement that the proposed area for the extension has been checked and found to show no sign of past soil disturbance or soft soli zones. This is to be established by conducting soil probing or sample digging in the zone of the proposed work.
  • For Clarification please note the following:
    • Where the addition is to be a slab on ground and the existing building is not similar such as suspended floor on pad footings, it will be acceptable to assess the performance of a slab on ground building on the adjoining property.
    • The “soil assessment” referred to above should take into account the potential for the site to have underlying rock strata that could affect the ability construct the proposed footing or slab.

 Certification from a Structural Engineer

Some of the parts of the BCA requiring structural adequacy only provide a technical method of designing a compliant building.
Unlike other kinds of structures (like a standard timber-framed house), there are no ‘span tables’ or similar documents referred to by the BCA that can be used to easily check if the design complies with these provisions of the BCA.
A structural engineer is the appropriate person to perform the calculations and checks needed to check a design meets the requirements of the standards that are referenced by the BCA.
The BCA lists a certificate from a professional engineer as an acceptable form of evidence that a design fulfils specific requirements of the BCA.

Times a structural engineer is required to certify ther structural design include:

• Steel framing and/or structural elements
• Slabs and/or footings outside the 'standard designs' in AS 2870 (this includes all 'P' class sites)
• Complex or high-risk construction types, techniques or buildings
• Timber framing outside the standard provisions of AS 1684

Other Supporting Documents  

Other documents should be attached to your application for a Construciton Certificate as appropriate.

These may include:

1. Copies of any compliance certificates relied on for the plans or specifications.
2. A copy of any relevant BASIX Certificate(s)
3. Details of provisions made for fire safety and fire-resisting construction.
4. A list of the existing fire safety measures installed in the building.
5. A list of the fire safety measures proposed to be installed in the building (not applicable for Class 1a or 10 buildings).