A box gutter, valley gutter, parallel gutter, or trough gutter is a rain gutter on a roof usually rectangular in shape; it may be lined with EPDM rubber, metal, asphalt, or roofing felt, and may be concealed behind a parapet or the eaves, or in a roof valley.
They are usually placed between parallel surfaces, as in a valley between parallel roofs or at the junction of a roof and a wall. Provision is made in the design of the gutter to have a rain flow to the outlet with a maximum slope of 1:200 and a minimum of 1:400
Valley gutters prevent water leaking into the fabric of a structure by channelling the excess water away. This prevents long-term damage to the building itself.
GRP Fibreglass is the ideal alternative to replace lead, valley or box gutters, whether it be an existing gutter or a new build, fibrespan will provide a continuous seamless membrane surface regardless of the size or complexity of the application, eliminating the risk of leaks normally associated with traditional lead linings.
Any roof is required to be built to allow excess water to discharge. This water drains to a gutter that leads away from the roof itself. A flat roof should have a watertight surface with a minimum finished fall of 1 in 80. When two pitched roofs meet at an angle, they also form a pitched valley gutter: the join is sealed with valley flashing.
