Core TradesQuestion 114 of 700
A water-resistive barrier (WRB) is being installed over wall sheathing. To shed water correctly, the horizontal laps must be arranged so that:
a.Upper courses tuck behind lower courses
b.All laps are sealed with tape only, in any order
c.The barrier is installed bottom to top with upper behind lower
d.Each upper course laps OVER the course below it, shingle-fashion, so water runs down the face
Explanation
A WRB must be lapped shingle-fashion with each upper course over the one below so gravity carries water down the outer face and never behind the barrier. Tucking upper behind lower, or relying on tape in the wrong order, lets water get behind the WRB.
Law Reference: 2025 CA Building Code / CRC (Weather Protection)Practice all 700 questions free — no signup required.
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