When installing asphalt shingle roof systems, contractors often
encounter brick masonry chimneys. If not properly detailed, water
may leak where a chimney intersects a roof system's plane. One
common method to avoid such a problem is to install a cricket.
A cricket is a relatively small roof area constructed to divert
water from a horizontal intersection of a roof and chimney. NRCA
recommends crickets be installed at the upslope side of chimneys
when a large volume of water, snow, ice or debris is expected; the
chimney is more than 24 inches wide; or the roof slope is 6-in-12
(27 degrees) or greater.
Crickets typically are constructed from metal. The metal type
and thickness used for cricket flashings should be commensurate
with the anticipated service life of the asphalt shingle roof
system. NRCA suggests cricket flashings for an asphalt shingle roof
system be fabricated from one of the following metal types and
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