Investigate an older house before demolition starts

Build an evidence record before opening up

Start with records, previous alterations, visible condition and the work you propose. Photograph the same locations and note when dampness, movement or service problems occur. A crack or stain is an observation, not a diagnosis. Ask an appropriate professional to identify likely causes, necessary investigations and any immediate restrictions on access or work.

This example concerns an older detached Sydney house. The proposed refresh keeps the footprint and has not yet reached demolition. Its budget does not assume the roof, structure or wiring is defective merely because of age. It also does not assume they are satisfactory because the rooms look tidy. The Your Home assessment approach helps identify what to retain, improve and investigate before design is fixed.

Match the question to the right specialist

Ask what is included in a visual inspection and what remains concealed. An inspector’s inaccessible-area note is a real limit, not proof that the hidden work is sound. If controlled opening-up is necessary, agree responsibility, reinstatement and hazard assessment first. Avoid commissioning several reports that answer the same narrow question while leaving the main decision unresolved.

Treat possible asbestos as a planning gate

The Asbestos and Silica Safety and Eradication Agency says a home built or renovated before 1990 may contain asbestos. That date is a reason to investigate, not a diagnosis of every material. Do not drill, sand or break a suspect surface to identify it. Arrange professional advice and testing where appropriate before disturbance; an ordinary visual building report may not establish material identity.

If asbestos is identified in the work area, use appropriately qualified and licensed professionals for the assessed work, confirm lawful transport and a receiving facility, and obtain the required records. Requirements depend on jurisdiction and material. This article does not offer a small-area DIY exception or sampling instructions. Keep ordinary skips and hazardous-material arrangements separate, and confirm current acceptance conditions rather than assuming a household collection programme is available.

Price the investigation before the renovation

In this invented example, final investigation allowances are AUD 1,800 structural, AUD 900 roof, AUD 700 moisture, AUD 800 electrical, AUD 900 plumbing/drainage and AUD 1,200 asbestos identification/testing: AUD 6,300 altogether. Agree deliverables, access and additional-test approval before commissioning. These are separate from the future work packages below.

All figures are final, including applicable tax, under the example assumptions. The AUD 7,500 is provisional; no asbestos has been confirmed by this table. It covers an assumed separate future professional work package, not the AUD 1,200 identification task. The AUD 9,500 repair allowance concerns one unresolved concealed repair outside the defined renovation package. The contingency base is AUD 82,000, excluding investigations and living/logistics costs.

Replace assumptions when evidence arrives

If professional investigation confirms no hazardous-material work is needed within the assessed scope, remove that AUD 7,500 allowance. Keeping the contingency fixed gives AUD 95,000. A negative result for one sample or area does not clear every concealed material in the house; retain the agreed controls and investigation boundaries.

If the named hidden repair is then defined at AUD 12,000 final, replace AUD 9,500 with AUD 12,000. Against the original model this produces AUD 105,000 with the reserve unchanged; if the hazardous-material allowance has also been removed, it produces AUD 97,500. State which scenario is being updated. Reassess the reserve if new findings widen the scope.

Authorise work only after the gates are resolved

• Record the assessed area, remaining limits and any urgent action.
• Resolve material identity before disturbing suspect areas.
• Turn findings into measured, priced work with clear exclusions.
• Confirm the sequence of cause repair, drying and reinstatement.
• Keep lawful waste arrangements and relevant completion records.

The NSW EPA renovation guidance supports checking the actual disposal arrangement and facility charges. No disposal operator has been verified for this example. Use Reno Pro to replace investigation allowances with accepted work and to record payments; it does not diagnose a building or make a concealed hazard safe.

Sources, date and scope

• Asbestos and Silica Safety and Eradication Agency — Householders and home renovators
• Australian Government, Your Home — Renovations and additions
• NSW EPA — Household building and renovation

Checked on 19 October 2026. Worked projects are in Sydney, NSW, unless stated otherwise. NSW rules are not national rules. All dollar amounts are Australian dollars (AUD); worked costs, quantities, margins and contingency percentages are invented teaching assumptions, not market prices, quotations or prescribed reserves. Each article describes a separate project. GST treatment is stated for the example; final amounts already include any applicable tax. Check the property, current approvals, insurance and contract with the appropriate professionals.