Contract documentation

Working drawings and specification

Once all key decisions are made and the owner has confirmed they are satisfied, construction documentation can start to allow the project to be priced, consented and built.

The main function of contract documents is to provide sufficient information to allow the contractor to perform the repair work in accordance with the contract and the Building Code. Pricing after the consent is obtained allows consent conditions imposed by the BCA to be incorporated by the contractors.

Consent documentation for remediation should include:

  • scope of works – a written description of the project and the work entailed
  • site plans identifying access to the site, location of services and where new and demolition materials can be stored
  • existing floor plans identifying bracing, expected wall damage locations and fittings that may need to be removed (such as kitchen units, window locations)
  • existing elevations identifying existing cladding, expected areas of damage, extent of wall cladding removal, estimated areas of framing damage and features to be removed such as decks or pergolas
  • existing cross-sections indicating where main structural elements occur that might be affected by damage and the envisaged potential extent of damage from a feature such as a cantilevered deck
  • proposed floor plans
  • proposed elevations highlighting new cladding, changes in appearance, and locations of specific construction details
  • proposed cross-sections showing new construction details (such as changes to roof form and new bracing details)
  • construction details covering:
    • integration of the existing with the new
    • wall cladding – wall top and bottom, corners, junctions
    • window and door penetrations
    • decks and balcony walls
    • flashings
    • new internal linings where required
    • critical junctions.
  • ground, floor and deck levels (existing and proposed)
  • site drainage.

The designer may also consider including a set of original documents as ‘information only’, which may reduce the need to redraw existing construction.

The written specifications for the work complement the working drawings by quantifying the scope of the work, identifying the materials and components to be used, listing the standards to be complied with, defining the quality of workmanship expected and listing any approved suppliers of materials or components.

As for other construction work, documentation for remedial projects should be specific to the remediation work rather than relying on general specifications.

At the completion of the working drawings and specification, designers should ensure that all potential weathertightness problems identified have been addressed in the repair solution. For example, while the new cladding is shown on a cavity, have any inadequate ground levels been addressed? Have the requirements for future maintenance and access for it to occur been considered?

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Peer review

Designers, particularly when new to this type of work, should also get remediation documents peer-reviewed by a designer experienced in this type of work or an NZIBS Building Surveyor.

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Contracts

A key part of any building project is the contract, which defines the roles and responsibilities of the parties to the contract – primarily the owner and the builder. Before obtaining prices, it is recommended that the designer provide the tenderers with a schedule of conditions outlining the existing state of a property or adjoining properties that may be affected by the project.

The Building Act requirements around contracts don’t just apply to builders, but to work done by any tradesperson. For residential building work of $30,000 (including GST) or over, you must have a written contract. There are certain things the contract must include – default clauses apply if the contract doesn’t contain the required information.

General conditions of contract can be based on a recognised standard form, such as NZS 3910 Conditions of contract for building and civil engineering construction or those from Master Builders, Certified Builders or the NZ Institute of Architects.

The general conditions of contract must work with and complement specific conditions for the remediation project. It is important that any contradictions between general and specific conditions are avoided, as these can lead to contractual problems and additional costs.

Specific remediation requirements to be incorporated into the contract documents should include:

  • required staging of work in multi-unit remediation if specific staging is required
  • responsibility and processes for determining the extent of damage once work is under way
  • responsibility for insurances and the required insured sums – for the building, the building works, materials stored off and on site and public liability
  • when site access is available and specific restrictions when working on a site
  • weather and other protection of the works and existing building elements
  • QA programme if required
  • access to existing facilities such as toilets and kitchens or whether they are to be provided by the contractor
  • any special conditions such as protection of existing vegetation (including on a neighbour’s property)
  • arrangements for access to a neighbour’s property (for example, use of a neighbour’s land may be required for scaffolding in some instances)
  • special protection requirements, such as building security where the owner’s property may remain in the building, or safety of occupants where a dwelling unit is not vacated
  • definition of the areas around the building(s) that are available for material storage, site huts and so on
  • specific health and safety requirements such as dealing with toxic moulds
  • procedures for dealing with issues that arise during construction
  • protection from damage of existing materials and finishes that are not being altered
  • authorisation process for the expenditure of monetary sums included in the contract
  • liquidated damages if any
  • contractors’ bonds
  • retention calculation
  • defects liability period
  • the builder’s rates for additional work not identified in the contract documents – an example would be the rate to replace rotten timber that was not allowed for.

Updated: 17 May 2017