When framing around windows in California seismic zones, what is required for the header construction in bearing walls?
Correct Answer
B) Double 2x header with 1/2-inch plywood spacer
CRC Section R602.7.2 requires headers in bearing walls to consist of double 2x lumber with a 1/2-inch plywood spacer or equivalent to match the wall thickness. This construction provides adequate strength for gravity loads and maintains wall plane continuity for seismic shear transfer, which is essential in California's high seismic risk areas.
Why This Is the Correct Answer
CRC Section R602.7.2 requires headers in bearing walls to consist of double 2x lumber with a 1/2-inch plywood spacer (or equivalent) to match the nominal wall thickness. This construction provides both gravity load capacity and continuity in the wall plane for seismic shear transfer, which is essential in California's high seismic risk areas.
Why the Other Options Are Wrong
Option A: Triple 2x header without spacer
A triple 2x header without a spacer would create a header thicker than a standard 2x4 or 2x6 wall, causing misalignment with the wall plane. The code does not call for a triple-ply header as the standard bearing wall solution; the double 2x with spacer is the code-required method.
Option C: Single 2x8 header with cripple studs
A single 2x8 header with cripple studs is insufficient for bearing walls under California seismic requirements. Single-ply headers do not provide the required load capacity or shear plane continuity mandated by the CRC for bearing wall openings.
Option D: Engineered beam only
Engineered beams are not required as the exclusive solution for all window headers in bearing walls. They may be used, but the CRC provides a prescriptive option (double 2x with 1/2-inch plywood spacer) that is the standard answer for this question.
Memory Technique
Visualize a 'sandwich' header: two pieces of 2x lumber with a 1/2-inch plywood filling in the middle. This sandwich fills the full wall thickness and gives you the strength plus the shear plane you need for seismic performance.
More trade-general-building Questions
When installing engineered lumber joists (I-joists) in California residential construction, what is the primary code requirement for web stiffeners?
What is the required attic ventilation ratio when a vapor retarder is installed on the warm-in-winter side of the ceiling according to the California Residential Code?
In California's Wildland-Urban Interface (WUI) areas, which underlayment requirement applies to Class A fire-rated roof assemblies?
In California, when installing a tankless water heater in a seismic zone, what additional requirement must be met beyond standard installation practices?
According to the California Building Code (CBC), what is the minimum lap splice length for #4 rebar in a concrete foundation wall in normal weight concrete with f'c = 3000 psi?
According to CBC requirements for retaining walls in California, what additional design consideration must be addressed for retaining walls over 4 feet in height located in seismic design categories D, E, and F?
When constructing retaining walls in California that exceed 4 feet in height, which CBC requirement must be met regarding drainage?
Under California regulations, when is a reduced pressure principle (RPP) backflow prevention assembly required for a residential water service connection?
Under California Title 24, what is the minimum electrical service size required for new single-family residential construction?
According to the California Building Code, buildings located in Seismic Design Category D must comply with which specific seismic design requirements?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass
Project Management
60 questions · 70% to pass
Related Study Resources
Previous Question
When installing engineered lumber joists (I-joists) in California, what is required at bearing points according to the CBC?
Next Question
In California, what is the required minimum horizontal distance between a private sewage disposal system absorption field and a water well according to the California Plumbing Code?