Knockdown Rebuild on a Narrow Block — Is It Possible?
Yes — a knockdown rebuild on a narrow block is absolutely possible. But it requires a floor plan designed specifically for the block width, careful management of side setbacks, and creative use of every square metre. Buildana (Lic. 487805C) has built custom homes on blocks as narrow as 10m frontage in Fairfield, Liverpool and Canterbury-Bankstown. Here is how it works.
What Counts as a Narrow Block?
In the context of Western Sydney KDRs:
• Standard block: 15m+ frontage. Comfortable for a standard home with double garage, side access, and generous facade. • Narrow block: 12–14m frontage. Feasible with careful design. Side setbacks limit the building width. • Very narrow block: Under 12m frontage. Challenging but buildable. The home will be long and narrow, with limited side setbacks.
Side setback requirements in most Western Sydney DCP controls: • 0.9m minimum to a boundary (single storey or ground floor) • 1.5m minimum for walls with windows facing the boundary • 0m setback to one boundary may be permitted for attached garages or party walls (varies by council)
On a 12m-wide block with 0.9m setbacks on both sides, the building width is limited to 10.2m. That is enough for a double garage (5.8m) plus a narrow entry and foyer. A functional 4-bedroom home can be designed within that width — but it requires a floor plan specialist, not a generic project home plan.
Design Strategies for Narrow Block KDRs
Building on a narrow block is a design challenge, not a deal-breaker. Strategies that work:
1. Long plan — bedrooms and living areas run front to back rather than side to side. The home is deep rather than wide.
2. Central corridor with rooms on both sides — maximises use of the available width.
3. Zero-lot-line on one side — building to one boundary (with appropriate fire-rated wall) and placing all setback on the other side. This creates one wider side yard rather than two unusable narrow strips.
4. Rear-loaded garage — garage accessed from a rear lane (if available) frees the front facade for living space.
5. Two-storey design — going up rather than out maximises floor area without consuming the full block. A 10m × 12m footprint (120 sqm per floor) creates a 240 sqm home on a narrow block.
6. Courtyard design — internal courtyards bring light and ventilation into the centre of a deep, narrow plan.
7. Roof terraces and balconies — where outdoor space at ground level is limited, upper-level outdoor areas compensate.
Buildana has designed homes for blocks as narrow as 10m in Merrylands, 10.5m in Bankstown, and 11m in Fairfield. Each required a custom plan — no project home template works on a narrow block.
Cost Implications of a Narrow Block KDR
Building on a narrow block does add some cost — but not dramatically.
Higher per-sqm construction cost: Narrow block homes tend to be deeper (longer front to back), which increases external wall area relative to floor area. External walls are one of the most expensive elements. A narrow block home may cost 5–10 per cent more per sqm than the same floor area on a wider block.
Scaffolding and access constraints: Narrow side setbacks limit construction vehicle and scaffold access. Materials may need to be craned over the building rather than delivered by forklift through a side access. This adds $5,000–$15,000.
Complex foundations: Narrow blocks near boundaries often require deeper foundations to avoid undermining neighbouring property footings. Edge beams and piers may be needed along boundaries. Additional cost: $5,000–$15,000.
However, narrow blocks in Western Sydney are often in older, established suburbs with strong land values — making a KDR an excellent investment despite the slightly higher per-sqm cost.
For broader block suitability guidance, see our is your block suitable for a KDR guide. For the full knockdown rebuild process, read our complete guide to knockdown rebuilds in Western Sydney. Contact Buildana for a free site assessment.
