Roxul ComfortBoard IS - Manual (Page 12)

ROXUL
® The Better Insulation™ 10
Window Installation
Perhaps the most common rainwater control failure occurs at window penetrations. Regardless of which
rain penetration control strategy is used, window and door penetrations through a cavity wall should be
drained. Sub-sill flashings (see Figure 4) of various types are widely available for this purpose. For
drained systems, the flashing can drain into the drainage gap.
Figure 4: To ensure resistance to rain penetration, sub-sill flashing below all window and door openings is a
critical requirement.
Figure 4 shows sub-sill flashing for “punched” (i.e., a window unit within a wall) window openings in a
section of wall. Other openings such as large curtain wall sections and patio doors should also be
protected with sub-sill flashing. Step-by-step instructions for integration of the window and drainage
plane are provided in the details section of this guide.