{{Short description|Type of rain gutter on a roof}} A '''box gutter''', '''internal 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.<ref>Dictionary of Architecture & Construction, C.M.Harris.</ref><ref name="ReferenceA">Glossary of Australian Building Terms - Third Edition.(NCRB)</ref>
Box gutters are essentially placed between parallel surfaces, as in a valley between parallel roofs or at the junction of a roof and a parapet wall. They should not be confused with so-called '''valley gutters''' or '''valley flashings''' which occur at the non-parallel intersection of roof surfaces, typically at right angled internal corners of pitched roofs. 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.
==Gallery of sketches== Note! The sketches in this section reference terminology commonly used in the UK and Australia.<ref name="ReferenceA"/> <gallery widths="200px" heights="220px"> File:Parapet-box-gutter.gif|A section through a box gutter at the intersection of the bottom of a sloping roof and a parapet wall. File:Parapet-gutter.gif| A simpler box gutter arrangement at a parapet wall that give a bare minimum of compliance to the Building Code of Australia (BCA) File:Boxed-valley-gutter.svg| A box gutter between two parallel roof surfaces. File:Triangle-gutter.gif| A sketch of a now illegal gutter construction under the BCA. A design to be avoided. </gallery>
==References== <references/>
==External links== *[https://web.archive.org/web/20121017003751/http://www.builderbill-diy-help.com/roof-glossary.html An Illustrated glossary of roofs and roofing terms.]
Category:Architectural elements Category:Roofs
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