Trims, Flashings, Gutters and Downspouts

Trims and flashings are formed steel pieces that close the edges and junctions of a metal building envelope. They cover the ridge, eaves, rakes, corners, openings and base, keeping water and wind out and giving the building a finished appearance. Gutters and downspouts collect rainwater from the roof and carry it to the drainage system.

Trims are usually press-braked or roll-formed from the same coated steel as the cladding so that color and durability match. They are fixed with sealed fasteners and used together with foam closures and sealants that fill the gaps between profiled sheets and flat trims.

Gutters can be eave gutters on the outside of the building, valley gutters between spans of a multi-span or multi-gable roof, or concealed gutters behind parapets and fascias. Gutter size and downspout spacing are selected for the roof area and the rainfall intensity specified for the site. Internal and valley gutters need overflows so that heavy storms do not cause water to enter the building.

Good detailing is the difference between a dry building and a leaking one. Laps are oriented with the water flow, sealants are placed where they are protected from sunlight, and trims allow for thermal movement of long sheets.

World Steel supplies a full range of trims, flashings, gutters and downspouts with each building, designed for the selected roof and wall systems and shown on the erection drawings.

When specifying, state the cladding system, colors, gutter type and the rainfall data or drainage design for the site. Valley and concealed gutters should be checked by the project designer for capacity and overflow, and downspout outlets coordinated with site drainage.