French Drain Installation

Small landscape infiltration trenches can use aggregate alone, but commercial collectors usually include perforated pipe for predictable conveyance, cleaning, and connection to an outlet. The design depends on inflow, soil, length, grade, maintenance, and loading. Stone without pipe still needs filter separation and a safe overflow or discharge path.

Many local systems use 100 or 150 mm pipe, but diameter is determined by contributing flow, length, slope, cleanout access, groundwater conditions, and the receiving outlet. Road and heavy-civil subdrains follow project standards. Harrowgate installs the designed size and verifies inverts rather than assuming one diameter fits every trench.

Positive continuous grade is more important than a generic figure. Roughly 0.5 to 1 percent is often practical where elevations allow, but hydraulic and site design may differ. Harrowgate surveys the outlet first, checks bedding during installation, and prevents hidden sags that collect sediment even when endpoints appear correct.

It can reduce groundwater beside the wall, but it does not repair cracks, penetrations, failed membrane, or surface runoff directed at the building. Effective work combines grading, perimeter drainage, waterproofing, drainage board, and an approved outlet. Harrowgate investigates the water path before selecting trench drainage alone.

Geotextile separates fine soil from open stone while allowing water to pass. Without compatible filtration, soil migrates into voids and gradually clogs the trench. Fabric type, overlap, and placement matter. A tightly woven product can also blind in silty soil, so selection follows geotechnical filter requirements.

It must go to an approved storm connection, swale, ditch, infiltration facility, sump system, or other lawful outlet that has capacity and does not affect neighbouring property. Water taking or discharge approvals can apply. Harrowgate confirms the design and receiving point before excavation rather than deciding discharge in the field.

Provide survey and grading, geotechnical information, wet-area history, utilities, proposed alignment, pipe and filter detail, outlet elevation, storm connection, access, shoring conditions, discharge requirements, and restoration limits. Harrowgate verifies line and grade, excavation volume, water control, materials, structures, and outlet protection before pricing.