What is a secret gutter?
A secret gutter is a gutter that lies largely beneath the roof tiles, so it is barely visible from outside. In Dutch it is called a verholen goot, from an old past participle of the verb for “to conceal”. In short: on a tiled roof, a secret gutter is a gutter that runs underneath the tiles. In everyday speech, an ordinary concealed gutter tucked behind a fascia board is sometimes also called a secret gutter.
Where do you find a secret gutter?
- Alongside the cheek of a dormer: water running down the cheek is caught in a narrow gutter between the cheek, the roof boarding and the tiles.
- Against a rising wall or taller neighbouring roof: for example where a tiled roof meets a brick gable or a chimney.
- Between two adjoining roofs of terraced houses with different tiles or roof pitches.
Construction
A secret gutter is usually a U-shaped or box-shaped profile of zinc, lead, aluminium or plastic resting on the counter battens or tiling battens. The tiles overhang the gutter slightly. At the top, the gutter has an upstand against the cheek or wall, often with a lead flashing over it. At the bottom, the water runs freely onto the tiles or into the eaves gutter.
Application
You mainly come across secret gutters when fitting or replacing a dormer, when renovating a tiled roof and at junctions between houses. There are also prefabricated renovation profiles and connecting pieces that are laid between two roofs.
Tips and points of attention
- Make it wide enough: a gutter that is too narrow quickly fills with leaves and moss and then overflows beneath the tiles, causing leaks alongside the dormer.
- High enough upstand: the edge against the cheek or wall must be higher than the water can rise in a heavy shower.
- Keep it clean: you cannot see a secret gutter, so you only notice dirt once it leaks. Lift a few tiles during maintenance to check.
- Patinate new lead: treat new lead flashings with patination oil, otherwise white lead carbonate can wash off and stain tiles and facade.
Related terms
- Gutter
- Box gutter
- Valley gutter
- Dormer
- Lead
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.