What is Cricket on roof?
A cricket, or saddle, in construction, is a triangular structure constructed to divert the surface water from the roof to the drains. It is designed on a flat or pitched roof mainly around the chimney, roof edges, curbs (Skylights and HVAC), drains, or wherever a 90° angle is formed on the roof. The main purpose of the cricket is to divert the water from the low slope and flat roofs with the parapet wall to the drain. A minimum of 2% of the slope is required for the water to drain smoothly, but cricket is more crucial to divert the water and also to protect the edges from penetration of water, which can lead to leakage and structure failure.
For steep slope roofs, it is advantageous to have a cricket pitch that is equal to or less than the present roof so that it has at least a 50% bigger slope than the actual roof to avoid water ponding on the roof. When water accumulates on a roof, it transports all of the debris and filth with it. Cricket can be designed or constructed with metal, wood, and concrete.
Places where cricket can be constructed
Roof crickets are constructed to divert the standing water from the flat roof and pitched roof. Given below are some places where we should design roof crickets.
- Parapet walls or Walls
- Curbs: Skylight, Gable window, and HVAC
Roof cricket near the parapet wall
The parapet walls are intended to handle rainfall and protect the roof’s edges. Flat roofs are designed to guide rainfall to drains or scuppers, although not all of the rainwater reaches the drain. There is a potential that some water will stay on the roof. Roof crickets are employed to channel rainfall towards the scupper to counteract this. It works, as seen in fig. 1. Roof crickets guard the margins of the parapet wall and the mid-wall.
Roof cricket around Skylight and HVAC
Cricket is not just used to divert the rainwater towards the drains; it is also used to protect the edges so that rainwater doesn’t harm the structure and penetrate the building. Roof cricket is also required for chimneys, HVAC systems, skylights, and other applications because there might be a chance that the rainwater remains around the HVAC unit and harms it. As you can see in fig. 2, we can construct a cricket around the HVAC to protect it from failure.
Roof cricket between the Drains or Scuppers
Drains can be placed anywhere on the roof, at the edges, or in the middle. It depends on the slope of the roof, which leads to rainwater. Wherever you place a drain or scupper, it requires roof cricket so that water doesn’t remain on the roof. See fig. 3 below for how it should be placed. Many roofs don’t have roof crickets. That’s why you can see green or black patches on them. Crickets should be used to avoid these patches.
The shapes in which crickets are designed
- Quarter Diamond
- Half Diamond
- Full Diamond
Where do we need roof cricket?
- Above a flat roof, on a slope.
- Around the edges of the chimney, HVAC units, skylights, etc.
- At any edge or junction.
Advantages of Using Roof Cricket
- Cricket diverts the flow of water.
- It makes it easier to find water.
- It stops the leakage of water and protects the structure from failure.
- Avoid ponding on the roof.
- This reduces the chances of green or black patches on the roof.