That little peak on the uphill side of a chimney has a practical job. Called a cricket or saddle, it sends rain around the chimney instead of letting runoff collect against its back. It is part of the roof, separate from the cap over the chimney opening.
If a leak has brought this detail to your attention, the useful question is whether the water has a clear route past the chimney and whether the connections keep it above the roof covering.
The raised shape gives runoff a way around
Rain moving down a roof meets an obstacle at a chimney. A cricket raises the middle of that intersection and creates sloping paths toward the sides. The water then returns to the main roof on either side of the chimney. A flat patch behind the chimney cannot create that change in direction.
The roof pitch, the width of the chimney across the slope and the roofing above it affect the shape that will work. A chimney near a roof intersection faces a different approach of water from one set in a simple, open slope. We look at that arrangement when checking the roof detail.
GAF’s roof-cricket guide describes this high-side water diverter and the different coverings used over it. The roof geometry needs assessment before choosing a new cricket or changing an existing one.
Flashing connects the small roof to the main one
The raised shape diverts runoff. Flashing, the metal around roof joints, connects that shape to the chimney and surrounding roof. A cricket can have a metal covering or its own small shingled slopes. Either arrangement still needs properly joined edges and the protective layers beneath it.
GAF’s shingle installation instructions illustrate the layer sequence: protection beneath the covering, fabricated cricket flashing, and shingles joined to its flanges. They treat a larger wood cricket as a small roof with its own valleys and flashing. Those are product instructions, so the exact installation must suit the material being used.
Sealant has a place in specified joints. Spreading it over the surface cannot add a missing water diverter, rebuild decayed support or put absent flashing behind the roofing. That is why a returning leak can require opening the connection instead of covering it with another patch.
A leak near the chimney is not a cricket diagnosis
A cricket can be present and the roof can still leak. A lifted edge, corroded metal or an opening where flashing meets the chimney can let water pass beneath the covering. We check these connections and the nearby shingles to work out what the roof repair needs to address.
GAF’s chimney-cricket guidance also points out that cracked masonry or loose mortar above the flashing can let moisture enter behind it. In that situation, roofing work alone does not fix the source of the water.
A mark beside the fireplace tells us where you noticed moisture; it does not identify the entry point. Tell us when you first saw it and whether that area has been worked on before. The inspection handles the roof-side investigation, including safe access to the area behind the chimney.
Adding or repairing a cricket during roof work
An existing cricket with sound support and a limited failed connection can need a local flashing repair. Damaged support or deteriorated adjoining material widens the opening needed to connect the repair properly. Adding a cricket to an otherwise serviceable roof also involves the surrounding roofing, because the new shape has to join it.
During roof replacement, this detail belongs in the roof plan before the new covering goes on. The roofer can account for the cricket, its underlayers, flashing and adjacent slopes together. The shape and applicable installation requirements need to fit the actual roof; the presence of a chimney alone does not settle the design.
Our roof flashing repair page explains how roof-to-wall connections are repaired. If you have a concern around your chimney, request a free roof inspection and tell us what you noticed. There is no need to climb up to inspect the cricket yourself.
