Commercial roofing requires the use of wall coping to protect a building’s structure. In this post we will highlight what coping cap is and the different types.
Types of Commercial Roofing
There are three principle components to low-slope commercial roofs:
• Weatherproofing layers– This is the most important element of the roof; it keeps water from entering a roof assembly. • Reinforcement– This adds strength, is puncture resistant, and adds dimensional stability to a membrane. • Surfacing– This component protects the weatherproofing and reinforcement from weather and sunlight. Some surfacing provides additional benefits such as increased resistance to fire, improved resistance to hail, and increased solar reflectivity.
What is Wall Coping?
Wall coping is a protective cap or cover on a wall that prevents water infiltration from above. This also acts as protective counter flashing for the top of the roof base flash at the wall. Materials used are concrete, metal, stone, and terra cotta.
Types of Wall Coping
- Attachment Method: Layering the bricks in a bed of mortar with epoxy. Epoxy binds them to the top of the wall.
- Joint Closure Method: Mortar or epoxy fills the joints between individual bricks.
- Standard Profiles: Bullnose (rounded at one end), Double Bullnose (rounded at both ends, Standard (flat ends). All the bricks are flat across the top, but a slanted coping can be formed during the installation.
- Typical Section Length: 3 ½ inches wide and 9 or 12 inches long.
Clay or Terracotta
- Attachment Method: They are set in a bed of mortar, and bonded to the top of the wall.
- Joint Closure Method: Individual coping pieces overlap each other, or each piece has a socket on one end that fits into the next piece. Mortar fills the laps/sockets.
- Standard Profiles: Camelback (low curved with a higher “hump” in the middle), Double-Slant slopes (slopes in both directions from the center), Single-Slant (Slopes in one direction), Streamline (low curved)
- Typical Section Length: 2 feet
Concrete (Pre-Cast) or “Cast Stone”
- Attachment Method: Holes are drilled into the bottom of the coping pieces and the top of the wall. Using grout or epoxy the holes are filled, and metal dowels/pins are inserted in the holes through the top of the wall. The pieces are then set onto protruding dowels. Dowels usually extend 2 inches into the wall and the coping.
- Joint Closure Method: Mortar is used to fill the joints, with building sealant in the top part of the joint.
- Standard Profiles: Bullnose (flat), Double Bullnose (flat), Double-Slant, Single-Slant, (custom profiles available)
- Typical Section Length: 2 – 4 feet, (custom lengths available)
- Attachment Method: Masonry anchors are installed in the top of the wall and extend above the wall. The anchors get embedded in the coping as the concrete is cast.
- Joint Closure Method: Control joints are tooled in the tops and sides of the concrete every couple of feet. This ensures that when the concrete cracks it occurs within the control joints.
- Standard Profiles: Forms are available for many different profiles.
- Typical Section Length: Varies according to the thickness of the coping. 2 to 10 feet.
- Attachment Method. Thermal expansion/contraction must be considering when attaching metal coping. The metal needs to be account for movement. Otherwise you run into fastener failure or deformation of the coping.Another method is using gasketed fasteners in the coping material. These slots let the metal move relative to the fasteners.
- Joint Closure Method. Joints are centered in the middle of a splice plate. The splice plate functions as an internal gutter to drain the water out of the coping system. The cleat system acts as a secondary water barrier when it covers the top of the wall. There will often be a metal cover plate/strip over the joint.
- Standard Profiles. Flat or Tapered (slopes in one direction)
- Typical Section Length. 8, 10, or 12 feet.
Why Does A Wall Need Coping?
A coping prevents water from entering a wall. Water infiltration can lead to water getting into the masonry of your home. Masonry is a porous material and when water gets in it can lead to white discoloration on the walls. This is due to the deposits of natural salts from the wall material.
To sum up this post a wall coping cap isn’t just to add to the aesthetic of your home, it protects your home’s structure. A coping cap is a necessary item if you want to protect your foundation’s integrity and avoid costly repairs later.