Patio Drainage Options + How to Install a Patio Drainage System | Unilock

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Patio Drainage Options + How to Install a Patio Drainage System in 9 Steps

Whether your backyard patio is an intimate escape or a grand gathering space, it can quickly turn into a muddy, slippery mess without proper drainage. 

We’ll explain how to install a patio drainage system using common patio drainage options, including permeable pavers and channel drains. 

Plus, we’ll share our extensive collection of sustainable, permeable pavers at Unilock, which you can combine with other drainage options as a foolproof solution for flooding.  

Explore permeable pavers at Unilock


Common Patio Drainage Options 

The most common patio drainage options are: 

  • Permeable pavers: Permeable pavers are designed to allow water to infiltrate through the surface, into the ground below. Permeable pavers are typically made of clay or pervious concrete. This type of paver acts as a natural drainage system to keep your patio from flooding due to heavy rain. At Unilock, our high-quality permeable pavers have a wide range of benefits, including optimal water absorption and striking design options. 
  • Channel drain: A channel drain, also known as a trench drain, is composed of a long, linear channel, typically made from precast concrete, polymer or metal. Channel drains can be installed in the middle or near the edge of your patio and are designed to capture and redirect water to a discharge point. 
  • French drain: A French drain, also known as a curtain drain, utilizes a buried, perforated pipe that is surrounded by gravel or coarse aggregate to collect and deflect water away from a patio. French drains are installed underground to prevent water from pooling on the top of your patio. 


Key Benefits of Installing a Patio Drainage System 

A patio drainage system allows you to protect your patio’s structural integrity while preventing flooding and soil erosion from occurring in your outdoor space. 

Key benefits of a patio drainage system include: 

  • Prevents potential accidents: When it rains, water can pool on your patio leading to slippery surfaces and potential accidents. A patio drainage system redirects water into the ground below, reducing the risk of a slip. 
  • Prevents soil erosion: Over time, water can cause the soil beneath the patio to erode, compromising its foundation. A drainage system helps prevent soil erosion, maintaining the structural integrity of your patio. 
  • Eliminates mold and mildew: Standing water creates the perfect environment for mold and mildew growth, which can damage your patio and pose potential health risks. In fact, mold and mildew can grow in less than 24 hours in this kind of environment. A drainage system keeps your patio dry, as it redirects water underneath rather than pooling on the surface. 
  • Protects landscaping: Need to protect your prized outdoor possessions — like your plants? A drainage system prevents excess water from pooling around the base of plants, minimizing the risk of overwatered conditions, such as root rot. 


Tools You’ll Need to Install a Patio Drainage System 

To install a patio drainage system, you will need the following tools and materials: 

  • Shovel to dig the trench 
  • Marking spray to label the location of the trench 
  • Level to ensure the channel drain is aligned 
  • Silt trap to prevent silt and other debris from clogging drain pipes 
  • Plastic drain pipes to transport water to a discharging point – like a storm drain system or a dry well 
  • Channel drain system components, including grates, end caps and outlet connectors to redirect water runoff from your patio 
  • Permeable or concrete pavers to finish the patio surface 
  • Quick-dry concrete to help you complete your drainage system project 
  • Bedding material, such as gravel, sand or crushed stone to serve as the drainage system base 
  • Plate compactor or hand tamper to compact gravel and polymeric sand 
  • Polymeric sand to fill joints between pavers 
  • Circular saw with a diamond blade to cut concrete or permeable pavers 
  • Wheelbarrow to transport materials such as soil, gravel, sand and pavers 
  • Pipe cutter or hacksaw to cut drainage pipes, if necessary 
  • Work gloves, safety goggles and respirator to protect yourself during the installation process 
A patio drainage system prevents soil erosion and flooding


How to Install a Channel Drain and Permeable Pavers as Your Patio Drainage System 

 For DIY patio projects, channel drains are easier to install compared to French drains, because they require less excavation and upkeep. 

When combined with permeable pavers, the two offer an ideal patio drainage system. 

Ready to roll up your sleeves? Here’s a step-by-step guide to installing a patio drainage system, combining a channel drain with permeable pavers. 


1. Lay Your Permeable Pavers

  • Mark the area: Outline the patio area using marking paint or stakes and string. 
  • Excavate the area: Dig out the marked area to a depth of about 8 to 9 inches deep. Make sure the bottom is level. 
  • Place geotextile fabric: Lay geotextile fabric on the excavated area to help prevent soil from mixing with the gravel and sand layers, ensuring proper water drainage. 
  • Install the base layer: Lay 4 to 6 inches of crushed stone or gravel evenly over the geotextile fabric. Compact the base layer using a plate compactor or tamper, ensuring it is level. 
  • Add a layer of sand: Add 1 inch of sand over the compacted base layer. Use a plate compactor to evenly spread the sand. 
  • Lay the pavers: Starting from the corner, begin laying the permeable pavers according to your chosen pattern. Use a rubber mallet to gently tap the pavers into the sand, making sure they are level with each other. 
  • Cut pavers to fit: Use a wet saw or chisel to cut pavers to fit around edges of the patio. 
  • Install edge restraints: Install edge restraints (composed of plastic, PVC, aluminum or steel) around your pavers to prevent them from shifting. To secure them, drive metal stakes into the ground below. 
  • Fill the joints: Sweep joint sand into the gaps between the pavers to lock them in place and allow water to flow through the joints. 
  • Compact and finish: Compact the pavers with a plate compactor, ensuring they are level and secure. Sweep any excess joint material off the surface. 
  • Seal the pavers (optional): Apply a paver sealant to help prevent staining and enhance color. At Unilock, our pavers are designed for optimal durability, with or without a sealer. 


2. Mark the Drain

Now that you have your permeable pavers in place, identify the best location for the channel drain. Ideally, the drain should run along the edge of your patio and slope gently towards the discharge point. 

Ensure the discharge point is at a safe distance from your home, garage or any other structure, like your local drain system. 


3. Mark the Trench Location

Using a string line and marking spray, outline the path of the trench where the channel drain will be installed. Ensure that the trench is slightly wider than the channel drain.  

As a good rule of thumb, allow an additional 2 inches. For example, if you’re installing a 4-inch channel drain, ensure your trench is 6 inches wide. 


4. Cut the Pavers (Optional)

If your patio is made of concrete or permeable pavers, use a circular saw with a diamond blade to cut along the marked line. 


5. Dig the Trench

Dig out the trench using a shovel and excavate 8 inches of soil to efficiently capture water runoff. 

Using a hand tamper, compact the soil to ensure proper water flow. 


6. Install the Channel Drain

Assemble the channel drain according to the manufacturer’s instructions. Add a silt trap just before the drain connects to the main drainage pipe, as silt can clog pipes, reducing the channel drain’s ability to remove surface water. 

To connect the drain to the plastic pipe (where the water will redirect from), attach end caps to the tip of the channel drain. 

Seal the joints of the plastic pipes using waterproof sealant to prevent leaks and improve durability. 

Then, place the assembled channel drain into the trench, ensuring that it slopes towards the discharge point. 

Use a level to check that the channel drain is aligned horizontally. Make any necessary adjustments by adding or removing soil beneath the channels. 


7. Backfill the Trench

Fill the gaps that are surrounding the channel drain with soil or gravel to secure them in place. 

Using a rubber mallet, compact the soil or gravel to keep it in place. 


8. Install the Grates

Place the grates on top of the channel drain, ensuring that they are secure. Cover the grates with plastic or tape to protect them from the concrete which will be added in the next step.


9. Add Concrete

If you have ready-mix concrete bags, just add water. 

If you need to prepare concrete from scratch, create the concrete mix according to the manufacturer’s instructions. 

Create a concrete mixture using the 1:2:3 mix of one part cement, two parts sand and three parts gravel. 

Pour the concrete on both sides of the channel drain to hold it in place. Remove the plastic or tape from the grates and cure the concrete for two days. 

Build your patio drainage system with a Unilock expert. Find a Unilock Authorized Contractor


Tips to Maintain a Patio Drainage System 

Once installed, your patio drainage system requires a little bit of maintenance to make sure it holds up over time to prevent flooding.  

To maintain your patio drainage system: 

  • Check your drainage system for signs of damage or blockage, such as cracks, broken or misaligned parts and debris. Make sure it is cleaned by a professional at least once a year. 
  • Clean the area surrounding your patio and drainage system by removing dirt and other materials that can clog your pipes and drains. 
  • Clean grates, drain covers and catch basins using a stiff brush or garden hose to ensure water flows smoothly. 
  • Flush the underground pipes at least once a week with a garden hose or pressure washer to remove any sediment or debris buildup. 
  • Inspect the surrounding landscape to ensure that water slopes away from your patio and promotes proper drainage. Address erosion or changes in landscape grading that can impact your drainage system.  


Explore Permeable Pavers as a Patio Drainage Option at Unilock 

As the first manufacturer to introduce permeable pavers in North America, we are proud to offer a comprehensive selection of permeable pavers designed for optimal water absorption. 

And as an industry leader in the retaining wall and paving stones industry, we manufacture the highest quality pavers, while offering exceptional customer service. 

Combine your French or channel drain with our permeable pavers to get the best drainage system results. 

Our permeable pavers are a green solution for managing stormwater runoff and reducing the risk of flooding and soil erosion in your outdoor area — whether a patio, a driveway or a permeable walkway 

Choose from a wide range of permeable pavers, including: 

  • Dura-Mat™ – Perfect for preventing soil erosion while growing vegetation in your backyard 
  • Eco-Optiloc™ – Ideal for patio projects that require optimal drainage, thanks to the 12mm gap between units 
  • Treo® Smooth – Perfect for patio surfaces that require a sleek look with a contemporary color palette 
  • Tribeca Cobble™ – Ideal for an eye-catching patio that you can call your own, thanks to imported granite and marble cobblestones
Unilock Eco-Optiloc™ pavers have a 12mm gap between units, resulting in optimal drainage


Our permeable pavers are manufactured with innovative technology, including:

  • Classic Coat: For those looking to enhance the color and protect the surface texture of our classic pavers, this factory-sealed coating is designed to save you time and money by eliminating the need for after-market sealing. 
  • EnduraColor: This refined surface of these pavers is designed from two-step manufacturing process, to ensure that your patio looks great for years to come. Coarser aggregates that provide a strong foundation are combined with wear-resistant finer aggregates and concentrated color on top to protect the surface of your pavers from wear and tear.

Whether you’re a DIY pro or a passionate beginner, our Unilock permeable pavers promise durability and striking designs that will leave a lasting impression on your outdoor oasis. 

Keep your patio safe and dry with Unilock. Explore permeable pavers!



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