Roof drainage directs rainwater from the roof to a discharge point. A siphonic system uses outlets and pipework designed to operate together.
Start with four questions
- What roof area drains into each zone?
- What rainfall data will be used for design?
- What elevation difference and pipe routes are available?
- Where does the water discharge, and what emergency overflow routes are provided?
Understand the components
Consider roof outlets, collector pipes, downpipes, connections, supports, gutters, and the receiving drainage system. Component selection must be coordinated with the network design.
Use the calculator as a starting point
The calculator helps explore roof area, rainfall intensity, and estimated flow. Final sizing requires a complete engineering review.