What actually drives a knockdown rebuild's cost?

A knockdown rebuild is often described as the price of a new home plus demolition. That leaves out many of the decisions that make one site different from another. A reliable cost conversation starts with the land, the design and the exact scope of work.

The existing site

Demolition is not a single standard line item. Access, what must be removed, neighbouring structures, services and site protection all affect the method. The work that follows can depend on levels, soil information, drainage and the way the new home sits on the block. If these details are unresolved, the tender needs to say which assumptions are being made rather than hiding them in a headline price.

The design and its details

Shape, structural spans, glazing, finishes and services can move cost significantly. A square-metre rate cannot tell you whether the price includes the same materials, site work or level of finish as another proposal. Plans and specifications should identify the choices you care about and the details that would otherwise become allowances. Consumer Affairs Victoria recommends reducing uncertain prime cost and provisional sum items where possible by specifying selections early.

The approval path and programme

The project's planning and building approvals depend on its location and design. A condition or design change can affect both the construction scope and timing. The programme should therefore include the approval and procurement dependencies, not just the on-site build. A date without the assumptions behind it is hard to rely on.

What to request in a tender

Ask for an itemised description of demolition, site preparation, the new home, external works and exclusions. Identify the source of any allowance, what would trigger a change and how that change would be priced. Compare the scope and specifications before comparing the final numbers. A lower figure with significant omissions may not be the lower project cost.

EJN Build's approach is to work from the site and drawings toward a clear scope and a programme that shows dependencies. We use written variations before changed work begins so price and timing can be considered together. Explore our knockdown rebuild service, or tell us about your project and we can identify what information is needed for a meaningful assessment.