4. There are two capillary breaks in this detail of an aluminum window: one between the sash and the frame, and another between the aluminum frame and the stone sill.

5. A parapet counterflashing can pull water by capillary action through the narrow crack between itself and the upturned edge of the roofing membrane underneath. This possibility can be avoided by bending the flashing so that it creates a capillary break.

A capillar^' break serves only to neutralize capillary action as a force that can move water through a building assemblv. It is a reliable and useful component of an overall strategy for making an assembly watertight, but it is not capable of resisting water penetration caused by gravity, momentum, or wind. ■

Metal Sash at Sill

Capillary break

5. Counterflashing

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