If a wall assembly requires R-19 insulation and you install R-13 fiberglass batts plus 1-inch rigid foam board with R-5, what is the total R-value?
Correct Answer
B) R-18
R-values are additive when insulation materials are installed in series. R-13 + R-5 = R-18 total. This assembly would not meet the R-19 requirement and would need additional insulation.
Why This Is the Correct Answer
R-values are additive when insulation materials are installed in series (one after another). The R-13 fiberglass batts and R-5 rigid foam board combine to give a total R-value of R-13 + R-5 = R-18. This is a straightforward addition calculation. The assembly falls short of the required R-19 by one R-value unit.
Why the Other Options Are Wrong
Option A: R-24
R-24 incorrectly suggests the R-values multiply or that there's some bonus effect. This would be R-13 + R-5 + 6 extra, which has no basis in insulation physics. R-values simply add together when materials are in series.
Option C: R-19
R-19 would be the required value, but this assumes the assembly meets the requirement. The actual calculation shows R-13 + R-5 = R-18, which is one R-value short of the R-19 requirement.
Option D: R-13
R-13 only accounts for the fiberglass batts and completely ignores the additional R-5 contribution from the rigid foam board. This fails to recognize that R-values are additive in series installations.
Memory Technique
Remember 'R-values ADD when installed in SERIES' - like adding layers of clothing, each layer adds warmth (R-value) to the total.
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?
Your crew discovers suspected asbestos-containing materials during a renovation project. What is the first action you should take?
A scaffold platform is 12 feet long and 5 feet wide. If the maximum load capacity is 25 pounds per square foot, what is the total weight capacity of this platform?
Which CSI MasterFormat Division would contain specifications for fire-stopping and firesafing materials?
In tilt-up concrete construction, what is the primary advantage of this method over conventional cast-in-place construction?
Which OSHA standard specifically addresses construction industry safety and health regulations?
A structural drawing shows a beam labeled 'W12x26'. What does the '26' represent?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass