G-03 Glossary term
Building coverage
The share of your site covered by building footprints when viewed from above.
Plain-language definition
Definition of Building coverage
The share of your site covered by building footprints when viewed from above.
What it means
Building coverage is the percentage of the net site area covered by building footprints. It usually counts the existing buildings and the proposed granny flat together, not just the new dwelling.
Look down from the sky
Floor area describes space inside a building. Building coverage asks how much ground the buildings occupy when viewed from above. A two-storey house may have far more floor area than footprint.
Roof overhangs or parts of a building extending beyond the ground-floor walls can affect the footprint under the national planning definition. The exact plan definition and measurement method must be used.
Worked example: Anika’s 600 m² site
| Measure | Area | What it means |
|---|---|---|
| Net site area | 600 m² | The denominator |
| 50% maximum | 300 m² | Maximum total coverage |
| Existing buildings | 205 m² | House, garage and counted footprints |
| Proposed granny flat | 70 m² | Proposed footprint |
| New total | 275 m² | 45.8% building coverage |
Three measurements to verify
- 01/
Net site area
This may not match the area at the top of a property record. The National Planning Standards definition excludes specified access areas and land subject to certain designations. Rear sites and shared access can make a material difference.
- 02/
Existing building footprint
Measure all buildings the applicable definition counts. Do not rely on the main house floor area alone; garages, sleepouts and other structures may form part of the total.
- 03/
Proposed building footprint
Use the final roof and wall geometry, not a rough internal floor-area number. Ask the designer to state the assumed footprint on the site plan.
Why coverage can change the design
If Anika adds a wide covered porch, changes the roof overhang or discovers that an old garage was omitted from the base drawing, the coverage calculation may change. A few square metres can matter on a tight site.
That does not always end the project. The footprint might be adjusted, an unused building removed, or a more lenient district-plan standard may apply. Each option needs checking against the full planning and building picture.
Coverage is not the same as
| Term | What it measures |
|---|---|
| Impervious area | Surfaces that do not absorb rainwater, which can include paving. |
| Floor area | Internal building area measured for a different purpose. |
| Yards or setbacks | Where a building can sit relative to boundaries. |
| Outdoor living space | Required usable outdoor area where those rules apply. |