Knocking down and rebuilding can work out cheaper than a big renovation, but not always. It depends on the condition of the house and what the planning rules allow. Here's what to weigh up.

Considering the costs of each option

If the house is in poor structural condition, knocking down and rebuilding may be cheaper and simpler than trying to fix it.

Repairing major structural damage, sourcing matching materials, and bringing an old house up to modern energy efficiency and quality can be expensive and slow. Be prepared to uncover more problems once you open things up.

The big one is asbestos. Homes built before 1990 may contain it. In Queensland, removing more than 10 m² must be done by a licensed asbestos removalist, and that cost applies whether you renovate or demolish.

But if you love the existing house, or most of the work is cosmetic, a renovation can be rewarding, and it can reduce your environmental footprint.

Overlays affect what you can renovate

If the house is heritage listed or in an overlay, tread carefully. Houses on your state heritage register are legally protected, and any proposed changes are closely examined to make sure they don't significantly alter the house's character.

Heritage and character overlays are areas set by councils with specific rules about changing existing buildings. In Brisbane, pre-1947 houses in character areas usually need council approval to demolish (the Traditional Building Character overlay). Check your council's planning scheme before you buy or budget, because councils enforce these rules strictly and can issue fines or stop-work notices for non-compliance.

Local authority regulations

Check whether the boundary rules have changed. You may not be able to knock down and rebuild in exactly the same position.

Setback rules (how close you can build to the boundary) may have changed since the house was built. If so, you might keep parts of the existing structure, such as the front facade, some external walls or the subfloor, so the project counts as a renovation rather than a rebuild. Whether it counts as a renovation is decided by council, so get that in writing before you design. Talk to council and your architect or building designer early.

You may not need to demolish everything!

If the house is structurally sound, the biggest gains often come from updating outdated, impractical layouts. A popular one is opening up living spaces by removing walls to create an open-plan kitchen, dining and living area.

Consider larger double-glazed or low-e windows for more natural light and better energy efficiency. A feature window or light well can also brighten the living areas.

Kitchens and bathrooms usually need modernising, and simple updates like new floor coverings, window furnishings, and rendering or plastering over old brickwork can transform a home.

Other things to consider

One advantage of renovating is you can often do it in stages and keep living in the house. If you can't, factor in the cost of somewhere else to live. And salvage and recycle materials where you can to recover some costs.

Summary

  • Knocking down can be cheaper than a big renovation, but it depends on the house's condition and the planning rules.
  • Asbestos in pre-1990 homes adds cost either way; over 10 m² needs a licensed removalist in Queensland.
  • Heritage listings and character overlays (like Brisbane's pre-1947 Traditional Building Character overlay) can restrict demolition and changes.
  • Check if boundary regulations have changed since the original construction; compromises may be needed if rules have shifted.
  • If the existing structure is sound, update outdated elements like living spaces, windows, bathrooms, and kitchens.
  • Renovating in stages can be advantageous, allowing you to continue living in the house during the process.