Wall capping is a protective layer installed on the top of freestanding walls and parapets to prevent rainwater penetration and protect the underlying masonry.
Purpose of Wall Capping
The primary function of wall capping is to shield the wall structure from the damaging effects of water ingress. Without proper capping, rainwater can seep into the wall, leading to:
- Structural Damage: Water weakens the mortar and masonry, causing cracks, crumbling, and potential collapse.
- Freeze-Thaw Damage: In colder climates, water freezes and expands within the wall, accelerating deterioration.
- Efflorescence: Water carries salts to the surface, resulting in unsightly white deposits.
- Biological Growth: Damp conditions promote the growth of moss, algae, and other organisms.
Materials Used for Wall Capping
Wall capping can be constructed from various materials, each with its own advantages and disadvantages:
- Metal: Common metals include lead, aluminum, zinc, copper, and plastic-coated steel. Metal cappings are durable and effective but can be more expensive.
- Masonry: Special bricks or masonry units designed specifically for capping are often used. These offer a cohesive aesthetic and good weather resistance.
- Concrete: Precast concrete copings are a cost-effective option, offering durability and ease of installation.
- Stone: Natural stone copings provide a premium aesthetic and excellent weather resistance.
Types of Wall Capping
- Flat Capping: A simple, flat surface that protects the wall.
- Saddle Capping: A peaked design that directs water away from the center of the wall.
- Weathered Capping: Angled to encourage water runoff in a specific direction.
- Coping Stones: Individual stone pieces used to create a capping.
Installation Considerations
Proper installation is crucial for the effectiveness of wall capping. Key considerations include:
- Overhang: The capping should overhang the wall on both sides to prevent water from running down the wall face.
- Drip Groove: A groove on the underside of the capping helps to direct water away from the wall.
- Sealing: Joints between capping sections should be properly sealed to prevent water penetration.
- Mortar or Adhesive: Use appropriate mortar or adhesive to securely attach the capping to the wall.
Wall capping is an essential element in masonry construction, safeguarding walls from water damage and ensuring their long-term durability and aesthetic appeal.
