Glossary.

Every planning, risk and market term you will see in Home Logbook, in plain English. Tap the ? icon anywhere in the app to jump back here.

Acid sulfate soil

Soil containing iron sulfides that, when disturbed by excavation or drainage, produce sulfuric acid that damages concrete, steel, and nearby waterways. Triggers extra planning controls when present.

BAL (Bushfire Attack Level)

A rating from BAL-LOW to BAL-FZ (Flame Zone) measuring how much heat or ember exposure a property faces during a bushfire. Higher BAL = stricter construction standards for new builds and major renovations.

Biodiversity area

Mapped land containing native vegetation, threatened species, or important habitat. Clearing or disturbance usually triggers a Biodiversity Development Assessment Report.

Coastal hazard

Land subject to coastal erosion, tidal inundation, or projected sea-level rise. Often carries development controls aimed at managing risk over a 50–100 year horizon.

Council

The local government area that issues planning approvals, building certificates, and rates notices for your property. Their LEP and DCP set most of the rules that apply.

DA (Development Application)

A formal request to your local council for permission to build, renovate, or change the use of a property. Required for most works beyond simple maintenance and like-for-like repairs.

Drinking water catchment

A catchment area that feeds a town water supply. Building, on-site sewer, and even land-use changes are tightly controlled to protect water quality downstream.

Easement

A legal right for someone else — council, neighbour, or utility — to use a defined strip of your land, commonly for drainage, sewerage, or access. You usually cannot build permanent structures over it.

Encumbrance

Any restriction on title — mortgage, easement, covenant, caveat — that affects what you can do with the land or transfers with it on sale.

Flood zone

Land mapped as at risk of flooding in a defined event (e.g. a 1-in-100-year flood). Triggers floor-level requirements, material restrictions, and sometimes higher insurance.

FSR (Floor Space Ratio)

A planning rule that limits how much floor area a building can have relative to its land size. An FSR of 0.5 on a 600m² block allows up to 300m² of total floor space across all storeys.

GFA (Gross Floor Area)

The total floor area of a building measured to the outer face of the external walls, excluding voids and some basements. GFA divided by site area gives the FSR.

Groundwater vulnerable land

Land where the water table is shallow or aquifers are easily contaminated. Excavation, dewatering, and chemical storage all face extra planning controls.

Height limit

The maximum building height permitted under the local planning instrument, usually measured in metres above natural ground level. Caps how many storeys you can add.

Heritage-listed

A property or street included on a heritage register because of historical, architectural, or cultural significance. Renovations, demolitions, and even external paint changes typically need council approval.

Landslide risk

Mapped areas where slope, geology, or rainfall patterns make landslip more likely. Council may require geotechnical reports before approving works.

Mine subsidence

Land within a designated district where historical underground mining can cause the ground to settle. Subsidence Advisory NSW must approve building work in these districts.

Overcapitalisation

Spending more on renovations than the property can return at sale. The classic example is a $300k kitchen in a $600k suburb median — most of that spend won't come back.

R1 General Residential

A flexible residential zone permitting a mix of housing types — houses, dual occupancies, multi-dwelling housing, and shop-top housing in some cases.

R2 Low Density Residential

Standard suburban zoning. Permits single houses, dual occupancies, and some home businesses, with height and density limits to preserve a low-density street character.

R3 Medium Density Residential

Allows townhouses, villas, and small apartment buildings alongside detached houses. Often applied to streets near town centres or transport corridors.

R4 High Density Residential

High-density apartment zoning, typically near major transport and town centres. Larger building envelopes and shorter setbacks than R1–R3.

R5 Large Lot Residential

Rural-residential zoning with large minimum lot sizes (often 1ha+). Detached houses only, frequently with restrictions on subdivision.

Renovation headroom

The gap between your last sale price and the suburb median. Positive headroom means there's room to spend on renovations before risking overcapitalisation; negative means you may already be at or above market.

Suburb median price

The middle sale price of all houses (or units) sold in the suburb over a recent period. We pull this from official suburb performance statistics — it's a market benchmark, not a valuation of your specific property.

Wetlands

Coastal or inland wetland areas with state environmental significance. Strict controls apply to drainage, vegetation removal, and any works within the wetland buffer.

Zoning

A planning category set by your local council that controls what you can build and how the land can be used. Common residential zones are R1 (general residential), R2 (low-density), R3 (medium-density), R4 (high-density), and R5 (large lot).