A roof area measures 2,400 square feet. Accounting for waste and ridge/hip factors, how many squares of shingles should be ordered?
Correct Answer
A) 28 squares
Base area is 24 squares (2,400 ÷ 100). Adding 15-20% for waste, cuts, and ridge/hip coverage: 24 × 1.17 = approximately 28 squares.
Why This Is the Correct Answer
Option A is correct because it properly accounts for waste and additional material needs. Starting with 2,400 sq ft = 24 squares, industry standard practice requires adding 15-20% for waste, cuts, starter strips, and ridge/hip coverage. Using 17% waste factor: 24 × 1.17 = 28.08 squares, which rounds to 28 squares. This ensures adequate material for proper installation.
Why the Other Options Are Wrong
Option B: 26 squares
26 squares only adds about 8% waste factor (26÷24 = 1.083), which is insufficient for typical roofing projects. This underestimates material needs and doesn't account for normal cutting waste, starter courses, ridge caps, and potential mistakes during installation.
Option C: 24 squares
24 squares represents only the base roof area calculation (2,400÷100) without any waste factor. This would result in material shortage as it doesn't account for cuts, waste, ridge/hip coverage, starter strips, or installation errors.
Option D: 30 squares
30 squares represents a 25% waste factor (30÷24 = 1.25), which is excessive for standard roofing projects. While conservative ordering prevents shortages, this level of overage increases project costs unnecessarily and exceeds typical industry standards.
Memory Technique
Remember 'WASH': Waste + Additional coverage + Starter strips + Hips/ridges = 15-20% extra squares needed beyond base calculation.
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