A Cologne gutter (Dutch “keulse goot”) is a concealed (hidden) roof gutter that carries rainwater not along the roof edge but internally — over or under the attic floor — to the other side of the building. The gutter therefore lies out of sight, within the roof structure, rather than visible on the façade. The name refers to the building tradition of the Rhineland around Cologne.
How it works
- The water enters a gutter that sits recessed within the roof shape
- From there it flows through the structure to a drainage point on the opposite or inner side
- The gutter is lined with zinc, lead, EPDM or another waterproof layer
Application
- Historic and formal buildings where a visible gutter was not wanted
- Situations where the façade continues up above the gutter, for example behind a parapet or cornice gable
Points to note
- Leakage risk: a concealed gutter lies above the occupied space; a leak is often noticed late, once there is already water damage beneath the attic floor
- Blockage by leaves or debris can cause serious damage to the floors below — fit leaf guards and inspect regularly
- Provide a generous gutter and a good overflow/emergency outlet so water can escape safely if it blocks
Related terms
- Gutter
- Roof gutter
- Box gutter
- Rainwater drainage
- Valley gutter
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