Councils in Canterbury have worked together to develop naming consistency for residential building inspections.

There are a number of checklists available for your reference on the Christchurch City Council website which cover the main checks carried out by a building inspector for each type of inspection.

When using this information, please note the following points below that are specific to Selwyn District Council.

Note: This information will be updated regularly when requirements change.

Site scrape/siting

Is required for residential and commercial buildings with single pour floors and ribraft floor systems to check the ground bearing and that site has been scraped with all vegetation and organic matter removed.

You’ll need a formal amendment to the building consent where a consented two pour floor system is changed to a single pour. Inspections can’t be booked until the amendment has been approved. If there’s no approved amendment, the inspector will fail the inspection and require a re-inspection allowing a section of the cut to be seen.

Site reports from engineer carrying out construction monitoring for your project need to clearly note that they have inspected the site scrape and confirm that all vegetation and organic matter has been removed. This engineer will need to be nominated and agreed at the time of consent application.

Foundation/waste pipes/floor slab

We generally carry out the following three inspections, exception for single pour floors and ribrafts where these will be combined

  • foundation
  • waste pipes
  • floor slab.

Pre-roof

We use the name pre-wrap for this inspection.

Pre-cladding

We use the name post-wrap for this inspection.

Note that windows don’t have to be in for a post wrap inspection if using a rigid air barrier to wrap the building.

Pre-stop

We don’t carry out these inspections unless the building consent includes a firewall and then it will be called up as a post-line inspection.

Tanking

We use the name internal membrane for this inspection.

These inspections were reintroduced on 1 September 2018 to provide better consumer confidence due to the high costs involved with membrane failures. Inspections are required (but not limited to)

  • bath plinths
  • tiled showers
  • wet floor showers
  • any tiled floor with a floor waste.

Tanking membrane inspection are not required for bath and vanity splashbacks.

The following documents must be onsite and in good condition before the tanking inspection (note this is not an exhaustive list of all inspection requirements)

  • issued building consent, including advice notes and schedule of inspections
  • consented/amended plans, supporting documents and specifications with the SDC approved stamp
  • copies of site inspection reports conducted by an engineer, where required
  • completed ‘construction statement - waterproofing’.

Drainage

The following vary from the provided checklist

  • soakholes need to be viewed under construction (not complete as noted on the checklist)
  • inspection of construction of the effluent bed and installation of septic tanks.

A heads up for drainlayers – not all is what it seems. Ask for test results before you purchase your filter sand (2A) for your effluent bed. This needs to comply with the requirements of NZS4407 and AS/NZS1547, particularly around the size of the sand grains.

Very fine sand binds together once wet and will likely form a crust. This prevents the correct filtering process from happening and eventually blocks the effluent bed, which can lead to system failure and become a substantial issue for the homeowner. Note that crushed glass may be used, however this must be signed off by the effluent system designer.

Final

In addition to items on the checklist, we’ll view the following

  • driveways
  • roof flashings
  • decks (if included in consent)
  • subfloor baseboards including venting & access
  • safety glass locations
  • interior water proofing and finishing.

If the driveway forms part of the building work covered by your building consent then it must be formed (dug out and boxed up) for the final inspection. This enables the inspection to check compliance with access and surface water. Please see the vehicle crossing information pack [PDF, 2628 KB] for information on Council requirements for vehicle crossings.

Safe tray requirements

A safe tray is required with storage water heaters when installed in household units and adjoining household units when

  • you’re installing a storage water heater (hot water cylinder), and
  • you didn’t have one installed previously, and
  • G12/AS1 is your chosen means of complying with the building code.

The purpose of installing a safe tray is to prevent water damage to dwellings caused by storage water heaters.

Safe trays are not required

  • in buildings that are not dwellings - unless there is an adjoining dwelling
  • buildings solely used as commercial buildings such as offices or warehouses
  • for non-storage water heaters, such as under-bench boilers/chillers and instantaneous water heaters.

If you’re replacing an existing storage water heater this is considered an ‘alteration to an existing building’ under the Building Act. Therefore where an existing storage water heater doesn’t have a safe tray, and is replaced as an alteration to an existing building, then a safe tray isn’t required. This is because the building only needs to comply to at least the same extent as before the alteration.

If a safe tray is difficult to install, in either a new or replacement situation, alternative solutions can include

  • locating the storage water heater outside
  • using instantaneous water heaters.
  • More details on safe tray requirements can be found in the New Zealand Building Code G12/VM1.