Siding & Exterior

Lap siding wall assembly — sheathing, house wrap, starter strip, flashing, and ground clearance

What goes on behind lap siding, bottom to top: sheathing, lapped house wrap, a starter strip that sets the first course angle, the nailed courses, and base flashing — with the siding held at least 6″ above finish grade.

Source: IRC R703.1 / R703.2 (6″ clearance) + manufacturer installation specs

What this diagram shows

A vertical cross-section of the bottom of a sided wall, layered from interior to exterior: framing studs, structural sheathing, a weather-resistive barrier (house wrap) lapped shingle-fashion to shed water, a starter strip that cants the first course out to match the rest, the lap-siding courses blind-nailed to the studs, and base drip flashing at the bottom. A dimension shows the 6-inch minimum clearance the code requires between the bottom of the siding and finish grade to keep the siding from wicking moisture.

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