FLASHING
Chimney flashing is a thin continuous pieces of sheet metal or other impervious material installed to prevent the passage of water into a structure from an angle or joint. Flashing generally operates on the principle that, for water to penetrate a joint, it must work itself upward against the force of gravity or in the case of wind-driven rain, it would have to follow a tortuous path during which the driving force will be dissipated. Exterior building materials can be configured with a non-continuous profile to defeat water surface tension.
|