Generally, where the work is outside the scope of the original consent (for example, additional footprint or increases in floor area, construction method, or significant changes to the layout), this would be considered a major variation. A formal amendment would be required for the new work to be undertaken.
Variations that are major often result when the variation impacts on a number of Building Code clauses.
The following examples demonstrate where compliance with the Building Code will be significantly affected (a major variation), therefore providing a trigger that a formal amendment is required. If approved, any amended application becomes part of the approved building consent documents file for that building project.
Examples of major variations
These examples are considered major variations because they impact on Building Code compliance and these changes need to be redrawn so the plans and specifications reflect what is to be built.
- A deck or carport shown on the building consent drawings is no longer to be built.
- The applicant wants an ensuite bathroom to be installed instead of a walk-in wardrobe shown on the building consent drawings.
- A change to the assembly (for example, acrylic shower unit to a tiled shower unit)
- Timber joists complying with NZS 3604 are shown on the building consent drawings, but the applicant is advised by the builder to change to a manufactured proprietary joist system.
- The applicant wants to change part, or all, of the proposed cladding system from that approved in the original consent.
- A new house is approved with a perimeter foundation wall and ordinary internal piles, but it is decided instead to construct a complete timber pile foundation.
The following scenarios outline situations of proposed variations that are major and require a formal amendment to consented building work:
|Scenario 1: The building inspector visits the site for the foundation inspection prior to pouring the perimeter foundation. On arrival the inspector is told the foundation is to be changed from slab on ground to a pile foundation.This would be a major variation because it is a significant departure from the approved building consent and the change could significantly affect the structural integrity of the building.
The inspector requests that work on site stops until the applicant has applied for a formal amendment (including new plans detailing the construction change) to the building consent and the amendment has been granted.
|Scenario 2: The plumbing inspector visits a site to undertake a pre-line plumbing inspection for a new two-storey dwelling. At the inspection, the inspector identifies that although the specification details a G13/AS1 graded stack compliant system, the plumber is about to install an AS/NZS 3500 elevated drainage system.
Because this is a completely different design principle at play,with different plumbing from the approved building consent,the inspector considers this a major variation and requires that a formal amendment to the consent be made. The plumbing work ceases until the new design has been documented, submitted to the BCA and the amendment is granted.
|Scenario 3: The plumber on a job tells the inspector that the owner wishes to install a roof-mounted solar water heating system rather than the mains pressure system detailed in the approved building consent.The inspector discusses with the builder and follows up with an inspection report/memorandum either in a letter or email explaining that a formal amendment to the consent will be required for the change.
This is a major variation and requires a formal amendment because the installation is considerably different from that approved. It also impacts on a number of other Building Code requirements such as Clauses E2 External Moisture, B2 Durability and B1 Structure where the solar water heating system may transfer a substantial load to structural roofing members.
|Scenario 4: The building inspector visits the site to undertake a pre-line building inspection. During the inspection the builder explains to the inspector that, although the drawings show an acrylic shower unit, the owner intends to install a wet area floor and tiles, walls and floor over a membrane.
The inspector sees this as a major variation. The inspector requires the owner and/or builder/designer to apply for a formal amendment to the consent for this work because it is a significant change to a complex construction method affecting a number of different Building Code requirements such as Clauses E3 Internal Moisture and B2 Durability.
|Scenario 5: A designer contacts the local building consent authority to explain that because of local supply issues she wishes to change the timber floor joists to a factory-manufactured flooring system. The designer provides the BCA with the design information and statements.
The building consent authority considers this to be a major variation and requires a formal amendment because the building was originally designed to NZS 3604 and the new flooring system falls outside of this Standard. The designer completes a formal amendment to the building consent and submits the information to the building consent authority for their assessment and approval.
|Scenario 6: During construction of a dwelling on a slope, the designer decides to increase the size of the excavation and change the detailed footing with a jack frame supporting the level above to a full height concrete block wall. The change is from a timber framed sub-floor to a concrete sub-floor structure.
This is considered a major variation because it is likely that an engineer will need to design the wall and footing.The designer will also need to detail how the wall will be‘tanked’ to prevent moisture passing through the wall.There may be also be drainage issues to consider.
While the above scenarios may assist in determining what is a major variation, building consent authorities will still be required to take into account individual circumstances with each variation they are dealing with.