Drain-tile pipe sizes & slope conventions
Drain tile (perforated pipe in gravel) carries water to a sump or daylight. Common pipe is 3–4 in, laid at about a 1% slope (~1 in per 8 ft) so it drains. These are stable conventions, not code — confirm local requirements. Apply them in the French drain and interior drain tile tools.
| Element | Convention | Notes |
|---|---|---|
| Pipe size | 3–4 in perforated | Corrugated or rigid PVC |
| Slope (fall) | ~1% (≈ 1 in per 8 ft) | Enough to drain, not so steep it silts |
| Gravel surround | washed stone | Wrap in filter fabric to resist clogging |
| Outlet | sump or daylight | Interior tile → sump; exterior → daylight if grade allows |
Timeless conventions, not a code reference — confirm pipe, slope and outlet requirements with your local building department.