Drainage boards

※  Product Description

Drainage boards are construction materials used in drainage and waterproofing systems. They are typically made from high-density polyethylene (HDPE) or polypropylene (PP) and have a surface with raised structures to create drainage channels.

※  The name of  Drainage boards

※  Executive Standard

GB18173.1-2012

※  Application

Material Features

1. Material Composition

High-Density Polyethylene (HDPE): Known for its durability, chemical resistance, and flexibility. It is widely used due to its excellent performance in tough environmental conditions.

Polypropylene (PP): Offers high impact resistance, low moisture absorption, and resistance to chemicals and stress. It’s often used in drainage boards where higher durability is required.

2. Water Drainage Efficiency

Dimpled Structure: Drainage boards typically have raised dimples or studs that create channels for water flow, allowing efficient drainage of excess groundwater or rainwater away from the structure.

Permeability: In some designs, they incorporate layers of geotextiles to filter fine particles while allowing water to pass through.

3. High Compressive Strength

Drainage boards can withstand heavy loads and pressure from soil, making them ideal for underground structures like foundations, basements, and retaining walls. This helps protect the waterproofing layers from damage during backfilling and settlement.

4. Chemical and UV Resistance

The materials used in drainage boards, especially HDPE and PP, are resistant to chemicals found in soil and water, such as acids, salts, and organic compounds.

Many drainage boards are UV-resistant, preventing degradation from sunlight, making them suitable for outdoor and rooftop applications.

5. Flexibility and Adaptability

Flexible Nature: Drainage boards are flexible and can conform to irregular surfaces, such as foundation walls, without cracking or breaking.

Lightweight: Despite their strength, they are lightweight, making them easy to handle, cut, and install.

6. Waterproofing Support

Drainage boards protect the waterproofing membrane by creating a separation layer between the membrane and soil, preventing punctures and mechanical damage.

7. Thermal Insulation

Some drainage boards also provide a degree of thermal insulation, which helps reduce temperature variations around the foundation, contributing to energy efficiency.

8. Environmental Friendliness

Many drainage boards are made from recycled materials, contributing to sustainability in construction projects.

※  Application

1. Basements and Foundation Walls

2. Green Roofs

3. Underground Parking Garage Roofs

4. Tunnels and Bridges

5. Retaining Walls

6. Artificial Lakes and Pools

7. Subways and Underground Passages

8. Roads and Airport Runways

9. Culverts and Drainage Channels

※ Construction Methods

1. Site Preparation

Clearing and Grading: Before installation, the site should be cleared of debris, and the surface graded to ensure proper slope for drainage. Any sharp objects or irregularities that could damage the drainage board or waterproofing membrane should be removed.

Waterproofing Layer Application: In most cases, a waterproofing membrane (such as liquid-applied or sheet membrane) is applied to the surface of walls, roofs, or foundations before the drainage board is installed to prevent water penetration.

2. Cutting and Fitting

Measuring and Cutting: Drainage boards are typically supplied in rolls or sheets. They should be measured and cut to the appropriate size using a utility knife or specialized cutting tool, ensuring they fit snugly to the surface where they are being installed.

Adapting to Irregular Surfaces: For surfaces that are irregular or have features like curves or corners, the drainage board should be cut and adjusted to fit securely without gaps.

3. Installation of Drainage Board

Orientation: The drainage board is typically installed with the dimples facing outward to create a drainage cavity between the waterproofing layer and the soil or backfill material.

Fixing to Surface: The drainage board can be mechanically fastened to the structure using fasteners, adhesives, or special anchors. This step ensures that the board stays in place during backfilling or subsequent construction activities.

Vertical or Horizontal Overlap: When multiple sheets or rolls are installed, they should overlap by a few inches to ensure continuous coverage and prevent gaps where water could enter.

Top Edge Sealing: The top edge of the drainage board is often sealed with a protective tape or flashing to prevent debris from entering the drainage channels.

4. Geotextile Layer (Optional)

Filter Layer: In some applications, especially in retaining walls or green roofs, a geotextile fabric is placed on top of the drainage board. This layer acts as a filter, allowing water to pass through while preventing soil particles from clogging the drainage channels.

5. Backfilling

Protective Layer: Once the drainage board is securely installed, backfilling can be done. The soil or backfill material is carefully placed against the drainage board to avoid damaging it.

Compacting the Backfill: The backfill should be compacted in layers to ensure stability, while being careful not to puncture or shift the drainage board. Heavy equipment should be avoided directly over the drainage board.

6. Connection to Drainage System

Water Collection and Discharge: Drainage boards are often connected to a drainage system such as perforated pipes, French drains, or sump pumps. Water collected by the drainage board channels is directed to these systems for discharge away from the structure.

Ensuring Slope: A slight slope should be maintained in the installation to direct water flow towards the drainage outlet, preventing water accumulation at the base of the structure.

7. Inspection and Maintenance

Inspection: After installation and backfilling, the drainage board should be inspected for any signs of damage or misalignment. Adjustments can be made before further construction takes place.

Maintenance: Once installed, the drainage board requires minimal maintenance. However, ensuring the drainage outlets remain clear and functional over time is important to prevent water buildup.

8. Special Considerations for Different Applications

Green Roofs: In green roof installations, the drainage board is often combined with other layers, such as waterproof membranes, root barriers, and lightweight soil, to ensure proper water management and plant growth.

Foundation Walls: For foundation wall applications, the drainage board must be installed from the footings to the surface level, ensuring full coverage of the wall.

Tunnels and Bridges: In tunnels and bridges, drainage boards may be used on vertical or horizontal surfaces and must be secured against high water pressure and ground movements.

※  Storage and Transport

1. Storage Conditions

Dry Environment: Store drainage boards in a dry area to prevent moisture accumulation, which could affect the material properties.

Temperature Control: Ideally, the storage area should be climate-controlled to avoid extreme temperatures that may warp or damage the boards.

Flat Surface: Store the boards on a flat, stable surface to prevent bending or deformation. Avoid placing heavy objects on top of them.

2. Protection from Elements

Covering: If storing outdoors or in an unprotected area, cover the drainage boards with tarps or protective sheets to shield them from rain, snow, and UV exposure.

Ventilation: Ensure good ventilation in the storage area to prevent moisture buildup and potential mold or mildew growth.

3. Handling and Transport

Careful Handling: When moving drainage boards, handle them with care to avoid bending or breaking. Use appropriate lifting techniques and tools, such as dollies or forklifts for heavier loads.

Secure Loading: During transport, securely load the drainage boards in the vehicle to prevent movement that could lead to damage. Use straps or tie-downs to keep them in place.

Avoid Stacking: If stacking boards for transport, ensure they are done so in a way that does not cause pressure points or deformation. Use spacers if necessary.

4. Transporting by Vehicle

Appropriate Vehicle: Use a vehicle with enough space to accommodate the size and quantity of drainage boards being transported, such as a truck or flatbed.

Minimize Travel Time: Plan routes to minimize travel time and avoid rough roads that could cause jostling and damage during transport.

5. Inspection Before Installation

Check for Damage: Before installation, inspect the drainage boards for any signs of damage that may have occurred during transport or storage. Look for cracks, bends, or any compromised sections.

Maintain Cleanliness: Ensure the boards are clean and free from dirt or debris that could interfere with their performance during installation.