ASh 12.2.1 Built-in Gutter (Design)

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ASh 12.2.1 Built-in Gutter (Design)

Division D - Construction Details

ASh 12.2.1 Built-in Gutter (Design)

Notice to Reader
Images used in a Construction Detail are representative and not prescriptive. Nor are they necessarily drawn to scale. Rather, they are provided to visually convey the requirements of the Standard they represent. Unless otherwise required by the Standard, dimensions, the selection of materials and their application remains the responsibility of the Design Authority.

The full text of the referenced requirements in the Standard may be read by using the blue hyperlinks
ASM Details



(1) Membranes
Membranes must be installed to RoofStar Guarantee Standards and the manufacturer's printed instructions (NOTE: Fasteners shall be installed 4” or more above the maximum water line, and gutters must include a scupper overflow drain.). Also refer to 9 Built-in Gutters in the RoofStar Guarantee Standards for ASM Roof Systems.
(2) Adhesion
Membranes must be fully adhered, where exposed, and mechanically fastened at terminations 300 mm (12") o/c
(3) Height
The minimum vertical sealed height above the maximum water level is 150 mm (6"). The membrane run up the slope will vary with roof pitch. Increase height in heavy snow regions.
(4) Eave Protection and Underlay
Built-in gutter membranes can be extended to act as an eave protection membrane. Underlay or eave protection membrane must overlap built-in gutter membrane by a minimum of 200 mm (8") and be installed in shingle fashion (not shown for clarity).


(A) Dimension
Dimensions of parapets, cants and water loading of gutters are variable and should be determined by design authority
(B) Acceptable Deck

NOTE: See the Standard for additional requirements.

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