Installing Stormwater and Subsoil Drainage Systems to Control Groundwater and Surface Runoff
Our team attended a property in North Turramurra to resolve ongoing water issues within a carpark area, where both groundwater and surface runoff were collecting against the structure. Areas like carparks are particularly vulnerable to water buildup due to surrounding hard surfaces and limited natural drainage.
For this project, Pure Plumbing Professionals installed a complete Stormwater Drainage and subsoil system, designed to capture water at multiple levels and redirect it safely into the existing drainage network.
This type of work focuses on long-term Drainage Solutions, ensuring water is managed before it can impact structural areas.
Why Carpark Drainage Problems Occur
Carparks often experience drainage issues due to a combination of surface and subsurface water movement.
Common causes include:
- Water runoff collecting against retaining or boundary walls
- Groundwater rising beneath concrete slabs
- Lack of proper drainage infrastructure
- Poor gradient preventing water from flowing away
Without proper drainage, water can build up and lead to:
- Ponding on concrete surfaces
- Moisture affecting structural walls
- Long-term deterioration of surrounding materials
In areas like North Turramurra, managing both surface and subsoil water is essential for effective drainage.
Identifying Water Entry Points and Planning the System
The first step involved identifying where water was entering and accumulating.
Our team:
- Located areas of groundwater runoff
- Marked out sections for drainage installation
- Planned trenching paths and connection points
Accurate planning ensures the system captures water at its source and directs it away efficiently.
Cutting and Preparing the Carpark Surface
To install the drainage system, sections of the existing concrete slab were cut and removed.
This allowed for:
- Trenching beneath the carpark
- Installation of drainage infrastructure
- Proper positioning of channel drains
A sand and cement base was then prepared to support the new drainage components.
This stage is a key part of Excavation Plumbing works where access is required beneath existing surfaces.
Installing Channel Drains for Surface Water
Channel grate drains were installed along the back wall of the carpark where water ingress was occurring.
These drains are designed to:
- Capture surface water runoff
- Prevent water pooling against walls
- Direct water into the drainage system
Channel drains are commonly used in Drainage Solutions for hard surface areas like driveways and carparks.
Installing Subsoil Drainage Behind the Wall
To manage groundwater, a subsoil drainage system was installed along the length of the carpark wall.
This involved:
- Excavating approximately 16 metres of trenching
- Preparing the trench base to achieve correct fall
- Installing subsoil (AG) drainage lines
- Wrapping the system in geotextile fabric
- Backfilling with drainage aggregate
Subsoil drainage collects water within the soil and redirects it before it reaches the surface or structure.
At Pure Plumbing Professionals, subsoil systems are essential for long-term protection in areas prone to groundwater buildup.
Waterproofing and Wall Protection
To further protect the structure, waterproofing was applied to the wall and footing areas below ground level.
This included:
- Installing builders plastic / coreflute as a barrier
- Applying two coats of waterproofing membrane
Waterproofing works together with Stormwater Drainage to prevent moisture from entering the structure while drainage systems redirect water away.
Connecting to the Stormwater System
The drainage system was connected to the existing stormwater infrastructure.
This involved:
- Core drilling through the wall to create an outlet
- Installing PVC stormwater pipework
- Connecting subsoil drainage into the main system
- Linking into existing downpipe and pit connections
Proper integration ensures that all collected water is safely discharged.
Installing Inspection Openings for Maintenance
Inspection openings were installed throughout the system to allow for:
- Future maintenance access
- Easy clearing of blockages
- Use of CCTV Drain Inspection if required
Including access points is a key part of professional drainage installation.
Reinstating the Carpark Surface
Once all drainage components were installed, the site was reinstated.
This included:
- Backfilling trenches with aggregate
- Reinstating the concrete slab
- Sealing around channel drains
These steps ensure the surface is restored while protecting the drainage system below.
Testing and Commissioning the System
After installation, the entire system was tested to confirm proper operation.
Testing ensured:
- Water was captured effectively by channel drains
- Subsoil drainage was functioning correctly
- Flow through the stormwater system was unrestricted
Final commissioning confirms the system is working as designed.
What Most Homeowners Don’t Realise About Carpark Drainage
Drainage problems in carparks are often caused by both surface and underground water.
Many people don’t realise:
- Surface drains alone cannot manage groundwater
- Waterproofing is needed to protect structural walls
- Proper gradient is critical for drainage performance
- Multiple systems must work together for effective results
This is why combined Drainage Solutions are used by Pure Plumbing Professionals.
When Carpark Drainage Systems Are Required
Drainage systems like this are typically needed when:
- Water pools in carpark areas
- Groundwater affects walls or slabs
- Drainage systems cannot handle rainfall
- Structural areas are exposed to moisture
Addressing these issues early helps prevent long-term damage.
Stormwater and Drainage Services in North Turramurra
Properties in North Turramurra often require tailored drainage systems due to terrain and water movement.
The team at Pure Plumbing Professionals provides:
- Stormwater Drainage Installation
- Subsoil Drainage systems
- Channel drain installation
- Waterproofing and structural protection
- Complete Drainage Solutions
Each project is designed to manage water effectively and protect the property.
If you’re experiencing water buildup in your carpark or around your property, a professionally installed drainage system can provide a long-term solution.
Call 0483 915 451 to speak with our team or click Book Now to arrange an inspection.
