Glossary
Updated 3 min readWorks without an account
FloorGen measures each room’s net area inside its walls and adds the walls for the gross area. What those are called depends on the project’s region: the UK says NIA and GEA, Germany NRF and BGF. This page explains each term.
Area terms in the plan summary
| Term | What it means |
|---|---|
| Net (interior) | Floor area inside the walls of each room. The area printed on a room is its net area. |
| Gross (to exterior walls) | Net plus the full thickness of the walls around each room. A wall shared by two rooms counts once. Called Gross (to outer walls) outside North America. |
| Net internal area (NIA) | The UK name for net. FloorGen’s figure is not a RICS measurement. |
| Gross external area (GEA) | The UK name for gross. |
| Net floor area (NRF) | The name for net in Germany, Austria and Switzerland. Wohnfläche also discounts low ceilings and open areas, which FloorGen does not. |
| Gross floor area (BGF) | The name for gross in Germany, Austria and Switzerland. |
| Surface habitable | The French name for net. The loi Carrez also leaves out areas under 1.80 m, which FloorGen does not. |
| Super built-up | Gross plus a loading percentage, set as Loading over gross. Shown when a loading is set, or when Areas lead with is set to Super built-up. |
| Above grade (gross) | Gross area of every floor except basements. |
| Below grade, basement (gross) | Gross area of the basements. |
| Balcony (open), Terrace (open) | Open areas, listed apart and left out of net and gross. |
| Plot coverage | Gross area of the ground floor as a share of the plot. Needs a plot size. |
| FAR | Floor area ratio: gross area of the ground and upper floors divided by the plot area. Needs a plot size. |
| Total height | The plinth plus the storeys above it. |
Other words FloorGen uses
| Term | What it means |
|---|---|
| Floor | One storey of the building: a basement, the ground floor or an upper floor. |
| Design | One version of a floor’s layout. Keep several to compare options. |
| Storey height | A floor’s height from its floor to the floor above, slab included. It stacks the floors and caps how tall a wall can be. 280 cm by default. See Heights and levels. |
| Slab | The floor structure above a storey, set as Slab thickness: 15 cm by default. |
| Clear height | The storey height less the slab: the room’s height up to the underside of the floor above. |
| Plinth | How far the ground floor stands above the plot, set as Plinth height (whole house). It lifts every floor except basements. |
| Level code | The short name on floor cards: B1 for the basement nearest the ground, G for the ground floor (S for a stilt level, with S+1… above it), then G+1, G+2… and Terrace. |
| Sill height | How high a window’s bottom edge sits above the floor. |
| Elevation | Two things: an item’s height above the floor, set as Elevation; and a side view of the building, see Elevations. |
| Pitch | The slope of a gable or hip roof in degrees, set as Pitch in the 3D view’s roof settings: 10° to 60°, 30° by default. |
| Building code profile | The rule set the checks use, such as IRC (US) or UK Approved Documents (England). The region picks it. |
| Print set | A PDF with a sheet per floor at a real scale and a title block. |
| Restore point | A saved version of the project in Version history… you can go back to. |
| Guest | Someone using FloorGen without an account. Projects stay in that browser. |
| MCP | Model Context Protocol, the way AI apps such as Claude and ChatGPT connect to FloorGen. |
Questions
Why doesn’t my room area match my measurement?
Room areas are net, inside the walls. If you measured to the outside of the walls, compare with the gross area.
How do I see FAR and plot coverage?
Open the plan summary and click Add plot size, then enter the plot’s width and depth.
How do I change which terms are used?
The terms follow the region, set under Region in Settings. See Language and units.