Minimum Freeboard Values
In gutters where overflow can enter the structure, freeboard is necessary to allow for wave action, obstructions, and other unforeseen circumstances. Freeboard is the height of the watertight portion of a gutter or profile above the design capacity (water level) at maximum rain intensity. Gutter Capacity Calculations allow for these minimum freeboard values.
Minimum Freeboard Values
| Gutter Type | Freeboard |
|---|---|
| Internal gutters | 30 mm |
| Secret gutters | 15 mm |
| Valleys > 8° | 15 mm |
| Valleys < 8° | 20 mm |
| Asymmetrical valleys | 20 mm |
| External gutters with overflow | No freeboard required |
| External gutters with no overflow | 15 mm |
Clause:
005_003_003_000_000_000_000_000_000
Clause Number:
5.3.3
/cop/roof-drainage/roof-drainage-design#minimum-freeboard-values
Revision Category:
2 - Editing and rearrangement