ASM Cylindrical Penetration (Flexible Boot Flashing)

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ASM Cylindrical Penetration (Flexible Boot Flashing)

Division D - Construction Details

ASM | Cylindrical Penetration (Flexible Boot Flashing) ( Article

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Images used in a Construction Detail are representative and not prescriptive, and are not necessarily drawn to scale. They are intended to support the related Standard (Ref. Division A, Article

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ASM Details

ASM 11.1.1.jpg

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(1) Underlayment
The type of underlay required is determined by roof slope.
(2) Insulation
Offset and stagger layers 300 mm (12").
(3) Vapour-permeable separation membrane
Installed over insulation and required on all insulated Architectural Sheet Metal Roof Systems. The material must be located between the insulation and metal panels/ventilation material (see 8.1.2 Design).
(4) Ventilation beneath panels
A ventilation space is required on slopes less than 1:3; entangled mesh (shown) may be used as void fill. The ventilation space facilitates drying as condensation forms on the underside of the metal panels.
(5) Architectural Metal Roof Panel
Clips not illustrated.
(6) to (10) Pipe Boot
  • Set in two continuous beads of acceptable sealant.
  • Secured with high-domed gasketed cladding-type screws.
  • Clamped to penetration with a stainless steel clamping ring (drawband).
  • Sealed between flashing and penetration.
(11) Water-tight storm collar
Installed by other trade (new construction only) or as required in this Standard. See 11.3.3 (5).


(A) Pipe penetration

NOTE: See the Standard for additional requirements.

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