A contractor needs to frame a garage door opening that is 16 feet wide in a bearing wall. What header construction does CBC require for this span?
Correct Answer
A) Engineered lumber beam
CBC requires engineered design for headers spanning 16 feet in bearing walls as this exceeds conventional framing span tables for dimensional lumber.
Why This Is the Correct Answer
CBC conventional framing (prescriptive) span tables for headers top out well below 16 feet for dimensional lumber in bearing walls. A 16-foot clear span in a bearing wall exceeds what standard prescriptive tables cover for double or triple 2x dimensional lumber headers, and the code therefore requires an engineered design — typically an LVL, PSL, or other engineered lumber beam sized by a licensed engineer or per manufacturer span tables. This is a fundamental code principle: when a condition exceeds prescriptive limits, engineering is required.
Why the Other Options Are Wrong
Option B: Double 2x12 with plywood spacer
A double 2x12 with plywood spacer is a conventional header assembly suitable for spans up to approximately 6-8 feet depending on loads and conditions — far short of a 16-foot garage door opening in a bearing wall. Using this assembly for a 16-foot span would result in excessive deflection and likely structural failure.
Option C: Steel beam with wood nailer
A steel beam with wood nailer could be an engineered solution, but it is not what CBC prescriptively 'requires' — CBC requires that the header be engineered, with the specific material selected by the engineer. The question asks what the code requires, and the answer is engineering design, not a specific steel beam.
Option D: Triple 2x12 header
A triple 2x12 header extends the capacity somewhat beyond a double 2x12 but still falls well short of adequately spanning 16 feet in a bearing wall under typical roof and floor loads. Dimensional lumber headers are not prescriptively rated for this span in bearing wall applications.
Memory Technique
Rule of thumb: when in doubt about a large span in a bearing wall, 'If it's over the table, call an engineer.' 16 feet is well above any conventional framing header table. Engineered lumber beam = the answer whenever the span is extraordinary. Think: 'Big opening = Big engineering.'
More California Questions
A contractor is installing shear walls in a residence located in Seismic Design Category D. The engineer's plans call for 15/32-inch structural sheathing with 8d nails at 6 inches on center at panel edges. The contractor wants to substitute 7/16-inch OSB with the same nailing. Is this substitution acceptable?
You are reviewing plans for a mixed-use building where the ground floor will house a restaurant with commercial kitchen equipment. The architect has specified standard residential electrical requirements throughout. What Title 24 compliance issue should you identify?
According to CBC seismic provisions, what is the concept behind the 'strong column, weak beam' design philosophy?
A residence in California has 2,800 sq ft of conditioned space. The HVAC system efficiency is 16 SEER. What is the approximate Title 24 compliance margin compared to the minimum 14 SEER requirement?
You're constructing a foundation on liquefiable soils identified in a California coastal area. The geotechnical report recommends deep foundations. Which option is most commonly specified?
A contractor is installing a heat recovery ventilation (HRV) system to comply with Title 24. The system serves a 2,000 sq ft house with 3 bedrooms. What is the minimum required ventilation rate?
During construction of a basement in sandy soil conditions, you encounter groundwater at 4 feet below grade. The basement extends 8 feet below grade. What is the critical design consideration per CBC?
During a seismic retrofit project, you discover that existing concrete has a compressive strength of 2,200 psi. The engineer specifies new anchor bolts that require 2,500 psi minimum concrete strength. What is the most appropriate action?
What is the maximum allowable notch depth in a 2x10 floor joist per CBC requirements?
You're reviewing plans for a wood-framed structure in seismic design category D. The project calls for a shear wall with 15/32-inch structural sheathing and 8d nails spaced 6 inches on center at panel edges. What is the allowable shear value per the CBC?
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
You are reviewing plans for a residence with radiant floor heating. Under Title 24, what is the maximum allowed heating system efficiency requirement for this installation?
Next Question
Calculate the required development length for a #6 rebar in 3,000 psi concrete with normal-weight aggregate in a seismic application. Use fy = 60,000 psi and assume all modification factors equal 1.0.