Countertop seam placement — where seams are forced and where they are forbidden
Seams are forced by slab size (runs over ~110″) and by inside corners. They are forbidden within 18″ of a sink or cooktop (AWI §3.3.1) and directly over a dishwasher (NSI 17-D-1). Green = allowed, red = forbidden.
What this diagram shows
A top-down plan view of an L-shaped kitchen countertop showing seam rules. Two things force a seam: a run longer than the slab usable length of about 110 inches (a 144-inch run must be seamed), and the inside corner of an L or U layout. Two things forbid a seam: it must stay at least 18 inches away from any sink or cooktop cutout per AWI section 3.3.1, and it must never cross the top of a dishwasher per NSI Drawing 17-D-1. Allowed seam locations are drawn in green, forbidden ones in red, with the 18-inch keep-away band shaded around the sink.
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