French Drain Case Study: Runoff Management in Shellharbour

Addressing Water Ingress Challenges in Shellharbour

In Shellharbour, a homeowner encountered a critical and worsening issue with water ingress. Water from two adjacent properties, situated at a higher elevation, began to flow into their garden and seep beneath the house's foundation. This water intrusion caused substantial damage to the flooring, promoted rising damp, and encouraged mould growth within the residence, jeopardising recent renovations.

How Can You Identify Signs of Water Intrusion?

The issue originated from surface runoff and subsurface water flowing downhill from the back and side yards of neighbouring properties. Without an effective drainage solution to intercept this water, it inevitably flowed beneath the home.

Creating an Effective Drainage System

CS Plumbing designed and installed a gravity-fed French drain system, aimed at capturing and redirecting water before it could reach the home's foundation.

This project incorporated several critical components:

A French drain system specifically designed to gather both surface and subsurface water from adjacent properties, efficiently channelling it via gravity to a concrete pit.
A 100mm PVC pipe connecting the pit to the curb, which features strategically drilled holes to ensure optimal water discharge.
Three new, larger-diameter Colorbond metal downpipes, replacing the original smaller versions, linked to new 100mm PVC piping extending to the curb.
A retaining wall system constructed along the boundary, utilising concrete sleepers and galvanised steel posts, with auger holes drilled using an excavator to create a robust barrier against the adjacent yard.
Effective soil removal conducted on-site with a dumper to facilitate streamlined management of the worksite.

What Measures Can You Implement for Effective Water Management?

The newly established system effectively captures both surface and subsurface water at the property boundary, ensuring it is diverted away from the house. The homeowner has achieved a durable, low-maintenance solution that safeguards the foundation, flooring, and their investment in renovations.