Brick is not typically permeable.
Understanding Brick Permeability
Generally, standard brick material itself has a relatively low permeability, meaning it does not allow water to pass through easily. The question of how permeable brick is often relates more to how brick surfaces (like walkways or patios) are installed rather than the inherent material properties of a single brick.
Typical Brick Installation & Drainage
Based on common practices and information such as the provided reference, brick is not typically permeable as a paving surface.
- Sand Substrate: Most brick pavers are installed over a sand substrate. This layer provides stability but isn't designed for water to drain through the brick and the sand layer itself.
- Surface Drainage: To manage rainwater, typical brick installations are sloped. According to the reference, they are often sloped at 2% to facilitate drainage off the surface and into nearby drainage systems or permeable areas. Water runs off the surface of the brick rather than soaking through it.
Permeable Brick Applications (The Exception)
While the brick material itself isn't highly permeable, brick systems can be designed to be permeable. This is achieved not by water passing through the brick, but by allowing water to drain between the bricks.
- Installation Method: Permeability is possible unless specifically installed with cracks between each paver where water can drain into a substrate of gravel.
- Drainage Through Joints: In these permeable installations, the gaps or cracks between the individual bricks are filled with permeable material (like small gravel or grit), and the substrate beneath is typically a layer of larger gravel, allowing water to filter down into the ground.
- Function: This type of installation is used in permeable paving systems designed to reduce stormwater runoff and recharge groundwater.
In summary, while individual bricks are not typically water-permeable, the way they are installed dictates whether a brick surface allows water to drain through its structure (permeable system) or shed water off its surface (typical non-permeable system).
