French Drain Design & Construction Supervision

Cal Engineering Drain Design & Repair in the Bay Area CA specializes in French Drain engineering design to protect properties from water seepage incoming from runoff / sheet flow or underground and high water table.

Few notes in the design process include but not limited to:

  1. FRENCH DRAIN SYSTEMS ARE SPECIALTY CONSTRUCTION ITEMS AND MUST BE SUPERVISED BY A REGISTERED CIVIL ENGINEER.
  2. TRENCH EXCAVATION MUST BE CLEAN & SLOPING AT A MINIMUM OF 2%.
  3. SHORING MUST BE USED TO PREVENT EARTH COLLAPSE.
  4. TRENCHING DEPTH BELOW GROUND ELEVATION IS INDICATED AT THE START AND END OF THE FRENCH DRAIN
  5. GEOTEXTILE FABRIC MESH SHALL BE MIRAFI 140N.
  6. PLACEMENT SHALL BE MADE IN THE FOLLOWING SEQUENCE: a) GEOTEXTILE MESH, b) 2″ LAYER OF DRAIN ROCKS, c) 4″ DIAMETER DRAIN PIPE WITH SOCK AROUND IT, d) DRAIN ROCKS TO TOP MINUS 8”-12” FROM GROUND ELEVATION, e) DOUBLE / OVERLAP FABRIC MESH COVER AT TOP, VERY IMPORTANT, f) ADD TOP SOIL TO GROUND LEVEL, g) LIGHT COMPACTION
  7. DRAIN ROCK SHALL BE OPEN DRAIN ¾”– 1½” WASHED CLEAN WITH NO FINES.
  8. DRAIN PIPE IN FRENCH DRAIN SHALL BE 4″ SOLID PERFORATED PLASTIC PIPE WITH SOCKS PROTECTION & HOLE INSTALLED AT BOTTOM.
  9. SUMP PUMPS TO BE INSTALLED, IF NEEDED WHERE DAYLIGHTING IS NOT POSSIBLE FOR DISCHARGE, THE TOP DISCHARGE EJECT LINE SHALL BE 1½” OR 2″ SOLID PVC PIPE INSTALLED 8-12″ BELOW GROUND LEADING TO APPROVED DISCHARGE FACILITY. SUMP PUMP IS TO BE INDUSTRIAL H.D. GRADE.
  10. ELECTRICAL WIRING TO BE INSTALLED BY LICENSED ELECTRICIAN