Build the demolition cost docket

One demolition rate cannot describe the site

Two buildings with the same floor area can have different structural systems, heights, foundations, access, hazardous materials and neighbours. A single dollar-per-square-metre rate can therefore look precise while omitting the items that control risk. This calculator makes users price separate work packages.

Soft strip is applied to gross floor area and can cover removal for reuse, fixtures, non-structural finishes and manual separation only when the entered quote says so. Structural or mechanical demolition is applied to a comparison volume: total floor area multiplied by average storey height. That volume is not a survey of concrete, brick or timber and must not be used as a disposal quantity.

Measure garages, sheds, pools, slabs, driveways, basements, retaining walls, tanks, trees and underground structures separately if they are outside the floor-area scope. Include making good to retained structures and the boundary. A “clear site” must be defined by finished levels, retained assets, imported fill, compaction, testing and erosion controls.

Survey hazardous materials before destructive work

The Australian Government asbestos agency advises that homes built or renovated before 1990 may contain asbestos. It is difficult to confirm asbestos by sight alone; an appropriate professional survey and accredited laboratory testing can identify material and condition. Demolition can turn hidden material into widespread contamination if investigation is delayed.

The asbestos area and rate are deliberately separate from ordinary demolition. The rate should state the material type, accessibility, removal class, notification, enclosure or control method, air monitoring where applicable, clearance, transport, licensed facility fees and records. Laws differ across jurisdictions, and some work must be performed by licensed removalists.

Other hazards can include lead paint, silica-containing masonry, synthetic mineral fibres, refrigerants, stored chemicals, mould, contaminated soil and biological waste. The survey allowance is not limited to asbestos. Make the demolition plan respond to the actual register or survey rather than a generic age assumption.

Demolition needs an engineered and safe sequence

Safe Work Australia’s model Code of Practice provides guidance on managing demolition risks, while state and territory regulators determine legal effect. Planning must consider structural collapse, falls, plant movement, services, fire, hazardous substances, noise, dust, adjacent structures and unauthorised entry.

Before work, establish how loads transfer and which elements provide bracing. Removing a roof, wall or slab out of sequence can destabilise retained work or neighbouring property. Temporary propping, exclusion zones and engineered methods belong in the scope before a contractor mobilises.

Locate, isolate and verify electricity, gas, water, sewer, communications, solar, batteries, fuel and other services. Capping for future redevelopment is different from temporary isolation. Obtain authority evidence and preserve any service that must remain live for neighbours or site controls.

Site establishment can include fencing, signage, amenities, access, emergency arrangements and security. Dust and traffic allowances may need water, monitoring, street occupation, spotters, covered loads, road cleaning, vibration controls or condition surveys. Local approval conditions can specify working hours and neighbour notification.

Price waste by verified streams and destinations

The calculator separates mixed waste from mineral material because transport and facility rates can differ. Enter estimated tonnes supported by a pre-demolition audit, quantity survey or contractor methodology. Confirm whether the facility charges by measured mass, volume, bin or minimum load and whether transport is included.

Source separation can improve recovery and reduce mixed disposal, but it needs space, sequencing and clean material. Concrete or brick contaminated with asbestos or other prohibited material cannot simply be treated as recyclable. Timber, metal, fixtures and architectural elements need an identified buyer or reuse route before a credit is reliable.

The salvage credit is deducted before contingency. Enter only a documented net credit after extra labour, storage, transport, marketplace fees and damage risk. If ownership of recovered materials transfers to the contractor, do not claim the same credit again. The calculator rejects a credit larger than the gross scope costs.

Keep weighbridge dockets, asbestos waste records, clearance evidence and facility receipts. They demonstrate what left the site and where it went. Illegal dumping or misclassification can create environmental, financial and reputational consequences beyond the original contract price.

Confirm the approval route in the correct jurisdiction

Demolition can be exempt, complying or subject to a development approval depending on building, location and local law. Heritage, bushfire, flood, trees, biodiversity, contamination, party walls and public land can affect the pathway. The NSW Planning Portal describes its state-specific routes, but those conditions should not be copied to another state or territory.

Approval does not replace work health and safety, asbestos, environmental, utility, road or waste duties. Establish who is responsible for certificates, notifications, inspections, neighbour communication and close-out documents. Do this before setting a demolition date or redevelopment programme.

Insurance and licensing requirements can depend on the work and jurisdiction. Check the contractor’s authority for the exact demolition and hazardous-material scope, not merely a general business registration. Ask how subcontractors are selected and controlled.

Compare tenders using one demolition scope

Issue the same reports and plans to every tenderer, allow a site inspection and require explicit exclusions. Check whether price changes if measured waste differs, hazardous material is found, access is delayed or the redevelopment requires a different final level.

Contingency is calculated after the documented salvage credit. GST is then added only if selected. Convert every entry to the same GST basis. A preliminary reserve cannot substitute for asbestos surveys, engineering, approvals or authority disconnections that are already foreseeable.

Define completion for the next project stage

A demolition contractor may finish when debris is removed, while a builder expects a surveyed, compacted, service-ready platform. Define retained trees and structures, temporary drainage, erosion controls, fencing, fill source, compaction tests, capped services and site access. Photograph boundaries and adjoining property before and after work.

New construction can expose demolition omissions: buried slabs, tanks, footings, contaminated fill or incorrect sewer capping. Decide who carries latent-condition risk and how discoveries are measured and approved. Keep demolition contingency available until handover evidence is accepted.

If redevelopment is delayed, budget ongoing security, weed control, dust, stormwater, rates, insurance and inspections. A vacant cleared site still has owner responsibilities. The calculator estimates the works described in its fields, not the holding cost between demolition and rebuilding.