Battle-Axe Lots and CDC: What You Can Actually Build Behind the Front Lot

A battle-axe lot can be one of the best-value sites in a Sydney street — quiet, private, and often cheaper per square metre. The catch is that the rulebook treats it differently. Here is the plain-English version of what a Complying Development Certificate lets you do on one, clause by clause.

If you own — or are eyeing — a block tucked in behind another house, you have probably had the same question land on your desk: can I just do this as a CDC, or am I stuck with a full DA? The honest answer is “it depends entirely on whether the lot ticks every box.” A battle-axe lot has its own set of those boxes. Miss one and the fast pathway closes.

This guide walks through the NSW Housing Code — Part 3 of the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 — as it applies to a new (or rebuilt) one or two storey dwelling house on a battle-axe lot. Every figure below is tied to a clause so you can check it yourself.

First, what is a battle-axe lot?

A battle-axe lot (also called a hatchet or flag lot) sits behind a street-fronting lot and reaches the road through a long, narrow strip — the “handle” or access laneway. The Housing Code describes it as a lot with three side boundaries and a rear boundary, where the rear boundary is the one opposite the face of the dwelling (cl 3.3(2)). In other words, it has no conventional street frontage, which is exactly why several of the standard rules are swapped out for battle-axe-specific ones.

Why CDC matters here

A Complying Development Certificate is a combined planning-and-construction approval. If a proposal meets every standard in the code, it can be certified — by a registered certifier or council — without a Development Application. The statutory determination window is 10 days (in practice the average runs longer), versus the months a contested DA can take. The trade-off is that CDC is strictly “as-of-right”: there is no merit assessment and no room to argue a variation. You either comply, or you don’t.

Does your battle-axe lot even qualify?

Before any design starts, the lot itself has to clear the eligibility gate at cl 3.1(3). For a dwelling house, all of the following must be true:

• The lot is zoned R1, R2, R3, R4 or RU5 (cl 3.1(3)(a)).

• The lot is at least 200 m² in area (cl 3.1(3)(b)).

• The lot is at least 6 m wide, measured at the building line (cl 3.1(3)(c)).

• There will be only one dwelling house on the lot at completion — a secondary dwelling (granny flat) doesn’t count against this (cl 3.1(3)(d) and 3.1(4)).

• The lot has lawful access to a public road at completion (cl 3.1(3)(e)).

• The battle-axe rule: the lot must be at least 12 m × 12 m, not counting the access laneway, and the access laneway must be at least 3 m wide (cl 3.1(3)(f)).

That last point is the one people trip on. The “12 × 12” is measured on the developable head of the block — the laneway is ignored. A long, skinny lot whose buildable rear is under 12 metres in either direction simply isn’t a Housing Code CDC site, no matter how big the total area looks on the title.

Before you design — pull the planning certificate. A lot can be knocked out of the code entirely even when it ticks cl 3.1(3): a heritage item, land flagged as susceptible to landslide risk, or other excluded land all rule out CDC (cl 3.2 and the Policy’s exclusions). A Planning Certificate (Section 10.7) confirms the zone, any exclusions, and — critically for battle-axe lots — registered easements over the handle. Get it first.

The build envelope: height, floor area, landscaping

Height — 8.5 m (cl 3.8)

The maximum height of the dwelling and any attached development is 8.5 m above existing ground level. Note that a basement — including a basement garage — counts as a storey (cl 3.1(2)), so a “two storey plus basement” design is really three storeys for code purposes and won’t fly.

Gross floor area (cl 3.9)

Maximum GFA scales with lot size. The key battle-axe twist: when you size the lot for GFA, the access laneway area is excluded (cl 3.9(2)). Your floor-area budget is set by the head of the axe, not the handle.

Lot area (laneway excluded) Maximum GFA

200 m² – 250 m² 78% of lot area

250 m² – 300 m² 75% of lot area

300 m² – 350 m² 235 m²

350 m² – 450 m² 25% of lot area + 150 m²

450 m² – 560 m² 290 m²

600 m² – 740 m² 335 m²

1,000 m² 400 m²

Intermediate bands (e.g. >560–600 m², >740–900 m²) taper at 25% of lot area + 150 m². Check cl 3.9 for the full table.

Landscaped area (cl 3.13)

You also have to keep a minimum proportion of the lot as deep-soil landscaping — from 10% on a 200–300 m² lot up to 45% above 1,500 m² — with each landscaped area at least 1.5 m wide and long. A patch of principal private open space is required too: at least 16 m² (lots 6–10 m wide) or 24 m² (wider), minimum 3 m × 3 m.

Setbacks on a battle-axe lot

This is the part that catches everyone, because a battle-axe lot doesn’t have a “front street” in the normal sense. The code handles it with three different rules — a front, sides, and rear.

Front — 3 m (cl 3.10(15))

Instead of the usual primary-road setback, a dwelling on a battle-axe lot must sit at least 3 m back from the boundary that its front faces — the shared boundary with the lot in front of it (cl 3.10(15)). (Battle-axe dwellings are also ignored when the council works out the street-setback average for neighbouring lots — cl 3.10(2)(a).)

Sides (cl 3.10(4))

A battle-axe lot has three side boundaries, and the side-setback table applies to each. For a typical lot the minimum is 900 mm, increasing once a wall gets tall:

Lot width at building line Wall height Minimum side setback

6 m – 10 m 0 – 5.5 m 900 mm

6 m – 10 m

5.5 – 8.5 m (height − 5.5) ÷ 4 + 0.9 m

10 m – 18 m 0 – 4.5 m 900 mm

10 m – 18 m 4.5 – 8.5 m (height − 4.5) ÷ 4 + 0.9 m

A wall can be built to one or both side boundaries in limited cases — for example, a lot 6–8 m wide where the wall has no openings and any neighbouring wall within 900 mm is masonry without windows (cl 3.10(5) and (6)). Walls within 900 mm of a side boundary are also capped at 3.3 m high (cl 3.10(7)).

Rear (cl 3.10(10))

The rear setback — to the boundary opposite the dwelling’s face — depends on lot area and building height:

Lot area Building height Minimum rear setback

200 m² – 900 m² 0 – 4.5 m (single storey) 3 m

300 m² – 900 m² 4.5 – 8.5 m (two storey) 8 m

900 m² – 1,500 m² 0 – 4.5 m 5 m

900 m² – 1,500 m² 4.5 – 8.5 m 12 m

So a two-storey home on a sub-900 m² battle-axe lot has to keep its upper level 8 m off the rear boundary — a constraint that often shapes the whole footprint on a tight block.

Parking and the forward-exit rule

At least one off-street car space is required, unless the lot is under 8 m wide at the building line (cl 3.16(1)). The battle-axe-specific catch is at cl 3.16(3): the parking space must be arranged so a vehicle can leave the lot in a forward direction. Reversing the full length of a long handle out onto the street isn’t acceptable, so you’ll usually need a turning area in the design. All parking and access must also meet AS/NZS 2890.1 (cl 3.16(2)).

What’s actually easier on a battle-axe lot

It’s not all extra hurdles. The street-presentation rules in cl 3.14 — the requirement for a door and window to a habitable room facing the road, the articulation-zone controls, the façade detailing — do not apply to a battle-axe lot (cl 3.14(1)). With no street to address, you get more freedom in how the front of the home is composed. Privacy still matters, though: the privacy-screen rules (cl 3.15) do apply, and they bite harder here because a battle-axe lot is usually hemmed in by neighbours on most sides. Expect to screen windows and raised decks that sit close to a side or rear boundary.

The deal-breakers

A single one of these will push the project off CDC and back to a DA:

• An easement under the building. Battle-axe lots frequently carry drainage, sewer, or right-of-carriageway easements down the handle. You can’t build over a registered easement (cl 3.2(1)(d)), bar a narrow exception for gutters, eaves, downpipes and underground drainage where the easement allows it (cl 3.2(2)).

• Heritage or excluded land. A heritage item or land otherwise excluded from the Policy is out — confirm via the planning certificate.

• Council variations. Schedule 3 of the Codes SEPP lets individual councils vary these standards for their area. The figures above are the state baseline; always check whether a Schedule 3 variation applies to your LGA before relying on them.

The short version

• Pull the planning certificate first — zone, exclusions, and easements over the handle.

• Confirm the head of the axe is at least 12 × 12 m (laneway excluded) and the handle is at least 3 m wide.

• Design to 3 m front, 900 mm-plus sides, 3 m or 8 m rear, within an 8.5 m height limit.

• Size floor area to the laneway-excluded lot area, and keep a forward-exit parking space.

• If any one test fails, it’s a DA — and a well-run DA is a different game worth planning for.

Frequently asked

Can you build on a battle-axe lot under a CDC? Yes — if it meets the Housing Code. The lot must be zoned R1, R2, R3, R4 or RU5, be at least 200 m², and the buildable part (excluding the access laneway) must be at least 12 m × 12 m with an access laneway at least 3 m wide (cl 3.1(3)). Miss any one of those and it’s a DA, not a CDC.

What are the setbacks for a battle-axe lot in NSW? Three apply: a 3 m front setback from the boundary the dwelling faces (cl 3.10(15)); side setbacks starting at 900 mm and increasing with wall height and lot width (cl 3.10(4)); and a rear setback of 3 m for a single-storey home or 8 m for a two-storey home on lots up to 900 m² (cl 3.10(10)).

How big can a house on a battle-axe lot be? Maximum height is 8.5 m above existing ground level (cl 3.8), and a basement counts as a storey. Maximum floor area scales with lot size (cl 3.9) — and crucially, the access laneway is excluded when sizing the lot, so your floor-area budget is based on the head of the block, not the handle.

What stops a battle-axe lot from qualifying for a CDC? The most common knock-outs are a registered easement running under the proposed building (cl 3.2(1)(d)), a heritage listing or other excluded land, or a Schedule 3 variation where a council has tightened the standards for its area. Confirm all three via the planning certificate before you design.

Not sure where your block lands? We assess battle-axe lots for CDC eligibility every week — and where the fast pathway doesn’t fit, we map the DA route instead. Send us the address and we’ll tell you what’s actually buildable before you commit to a design. Link Teale, Design Manager — 0403 993 876, link@planland.com.au, planland.com.au.

This article is general information about the NSW Housing Code (Part 3 of the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008) as in force at the time of writing. It is not legal or planning advice. The standards cited are the state baseline and may be changed by a Schedule 3 council variation or by a site-specific exclusion. Always verify against the in-force Codes SEPP and engage a registered certifier or town planner for your specific property.