What is an Inspection Test Plan (ITP) in Construction?

An Inspection Test Plan — commonly called an ITP — is a document that defines every quality checkpoint on a construction project, what needs to be checked at each point, who checks it, and what the acceptance criteria are. For residential builders, ITPs are increasingly being requested by certifiers and are a practical tool for catching defects before they are covered up by subsequent work. For commercial builders, they are often a contractual requirement.

How an ITP is structured

A typical construction ITP is organised by work activity or stage. For each activity, the ITP specifies:

• The inspection point — what is being inspected and at what stage of the work
• The inspection type — witness (you must be present), hold (work cannot proceed without sign-off), or review (documentation review only)
• Who inspects — builder's supervisor, independent inspector, certifier, or engineer
• The acceptance criteria — what standard must be met for the inspection to pass
• The reference document — which standard, specification, or NCC clause applies
• The sign-off field — who signed it off and when

The completed ITP becomes a quality record showing that each inspection was carried out and met the required standard. This is the document that protects you if a defect claim arises years later.

Hold points versus witness points

The most important distinction in an ITP is between hold points and witness points. A hold point means work cannot proceed past this stage without a sign-off. If the certifier has a hold point at pre-pour inspection of the slab, no concrete can be poured until they have physically attended and signed off.

A witness point is one where the relevant party is notified and given the opportunity to attend, but if they do not attend after adequate notice, work can proceed. Most inspection points on residential projects are witness points rather than hold points — hold points are reserved for the highest-risk activities where proceeding without inspection would be unacceptable.

What ITPs cover on a residential build

A residential ITP typically covers inspection points at:

• Excavation and base preparation
• Slab reinforcement and formwork pre-pour
• Frame — completion of structural framing
• Wet area waterproofing before tiling
• External wall cladding and weatherproofing
• Insulation installation
• Rough-in services (electrical, plumbing, air conditioning) before lining
• Internal lining (plasterboard) completion
• Pre-handover defect inspection

The specific inspection points depend on the project type, the applicable standards, and the certifier's requirements. For projects with engineered elements, the engineer will typically have their own hold and witness points that need to be incorporated.

Why use an ITP on residential builds?

Many residential builders only encounter ITPs when a developer or certifier asks for one. But running your own ITP — even a simplified one — has real practical benefits. It forces a quality check at each stage before work is covered up, creates a documented record if a defect claim arises, gives subcontractors a clear quality standard to work to, and demonstrates to clients and certifiers that quality management is systematic rather than ad hoc.

The cost of catching a waterproofing defect before tiles go down is a fraction of the cost of fixing it after. An ITP hold point at that stage pays for itself the first time it catches something.