Pre-Line Inspection Software for NZ Builders & Inspectors

The pre-line stage is the last point in the construction process where internal services — plumbing, electrical wiring, insulation, ventilation ducting, and fire stopping — are fully visible and accessible. Once plasterboard or other wall and ceiling linings are installed, these services are permanently concealed. If there is a plumbing leak, an incorrectly rated insulation batt, a missing fire stop, or a wiring defect behind the linings, the only way to find and fix it is to remove the linings — an expensive and disruptive process that no homeowner or builder wants to face.

New Zealand's Building Code imposes specific requirements on each service concealed at the pre-line stage. Clause G12 (Water Supplies) governs potable water systems, requiring correct pipe sizing, support, and pressure testing. Clause G13 (Foul Water) covers wastewater and drainage systems, requiring correct falls, venting, and trap sealing. Clause H1 (Energy Efficiency) mandates minimum insulation R-values for walls, ceilings, and floors — values that vary by climate zone across New Zealand. Clause C (Protection from Fire) requires fire stopping at all penetrations through fire-rated walls and floors, and correct installation of smoke alarms.

Council building inspectors conduct a pre-line inspection as a prescribed hold point, verifying that insulation is installed and that plumbing and electrical work appears to comply with the relevant standards. However, the council inspection is a compliance check — not a quality audit. An independent pre-line inspection goes further, verifying insulation R-values against the H1 schedule for the specific climate zone, checking that insulation is properly fitted without compression or gaps (which dramatically reduce thermal performance), confirming plumbing pressure test results, documenting fire stopping at every rated penetration, and checking ventilation provisions for bathrooms, kitchens, and subfloor spaces.

Common findings at the pre-line stage include incorrect insulation R-values (particularly in climate zones 1 and 2 where builders sometimes use R2.2 wall batts instead of the required R2.6), insulation that is compressed behind services or cut to fit around obstacles without replacement, missing fire stopping at penetrations through inter-tenancy walls in multi-unit developments, plumbing that has not been pressure-tested, and insufficient bathroom ventilation provisions. Each of these issues has code compliance implications and can lead to comfort, health, or safety problems for the building's occupants.

For inspectors conducting new build inspections in New Zealand, the pre-line stage is photographically intensive. Every wall cavity, every ceiling space, every penetration through a fire-rated element must be documented. InspectPro is designed for this volume of documentation — structured templates guide you through each area, photos are automatically organised by section, and annotations let you flag issues directly on the image so your report is clear, professional, and unambiguous.