ILLINOIS ROOFING EXAM PRACTICE QUESTIONS
COMPLETE WITH 100% CORRECT ANSWERS AND
EXPLANATIONS
1
What is the minimum slope for asphalt shingles on a residential roof in
Illinois according to most building codes?
A 4:12 (Correct)
B 2:12
C 1:12
D 3:12
Explanation: Asphalt shingles require a minimum slope of 4:12 to
ensure proper water runoff and prevent leakage under normal weather
conditions.
2
Which type of underlayment is required for roofs with slopes below
4:12 in Illinois?
A Self-adhering polymer-modified bitumen (Correct)
B Asphalt-saturated felt
C Non-permeable plastic sheeting
D Gypsum board
Explanation: For low-slope roofs (2:12 to 4:12), self-adhering
underlayment (ice and water shield) is required as a secondary barrier
against wind-driven rain and ice dams.
,3
What is the maximum allowable spacing for nails on asphalt shingles
per the Illinois State Plumbing and Roofing Code?
A 6 inches on center
B 12 inches on center
C 4 inches on center
D 8 inches on center (Correct)
Explanation: Standard code requires nails to be spaced no more than 8
inches apart and no less than 2 inches from shingle edges to prevent
lifting.
4
When installing ice and water shield on an Illinois home, how far must it
extend from the interior wall line?
A 12 inches
B 36 inches (Correct)
C 18 inches
D 24 inches
Explanation: Ice and water shield must extend at least 36 inches from
the interior warm wall line to prevent ice dam leakage in Illinois climate.
5
Which of the following fasteners is prohibited for attaching metal roof
panels in Illinois?
A Galvanized roofing nails
B Stainless steel screws
C Electroplated smooth shank nails (Correct)
D Polypropylene coated screws
Explanation: Electroplated nails lack corrosion resistance and are not
approved for metal roofing due to rust risk under thermal cycling.
,6
What is the minimum headlap for double-coverage asphalt shingles?
A 8 inches
B 10 inches
C 12 inches (Correct)
D 6 inches
Explanation: Double-coverage shingles require a 12-inch headlap to
ensure two layers of material cover the roof deck at any point.
7
A roofer in Illinois must register with which state agency before
performing work over $1,000?
A Illinois Department of Transportation
B Illinois Department of Financial and Professional Regulation (Correct)
C Illinois Roofing Association
D Illinois Attorney General
Explanation: Roofing contractors must register as a roofing contractor
with IDFPR under the Illinois Roofing Industry Licensing Act.
8
What type of vent is required for attics with asphalt shingles to prevent
condensation?
A Ridge vent with continuous soffit intake (Correct)
B Gable vent only
C Turbine vent without soffit
D Powered fan only
Explanation: Balanced ventilation (ridge + soffit) is required to maintain
airflow and prevent moisture buildup under shingles.
, 9
What is the minimum thickness for plywood roof decking under asphalt
shingles in Illinois?
A 7/16 inch (Correct)
B 1/2 inch
C 3/8 inch
D 5/8 inch
Explanation: 7/16 inch OSB or plywood is the minimum accepted by
code for standard shingle installation.
10
Which underlayment is acceptable for use under clay tile roofs in
Illinois?
A 60-minute felt paper (Correct)
B 15-pound felt
C Plastic vapor barrier
D Single-ply EPDM
Explanation: Clay tile requires a 60-minute or heavier underlayment for
additional waterproofing due to tile porosity.
11
A roofing contractor in Illinois who fails to provide a written contract for
work over $1,000 is subject to what penalty?
A License suspension only
B No penalty if work quality is good
C Fine up to $10,000 and possible license revocation (Correct)
D Mandatory retraining
Explanation: IDFPR rules require written contracts for any roofing work
over $1,000; violation can lead to fines and license action.
COMPLETE WITH 100% CORRECT ANSWERS AND
EXPLANATIONS
1
What is the minimum slope for asphalt shingles on a residential roof in
Illinois according to most building codes?
A 4:12 (Correct)
B 2:12
C 1:12
D 3:12
Explanation: Asphalt shingles require a minimum slope of 4:12 to
ensure proper water runoff and prevent leakage under normal weather
conditions.
2
Which type of underlayment is required for roofs with slopes below
4:12 in Illinois?
A Self-adhering polymer-modified bitumen (Correct)
B Asphalt-saturated felt
C Non-permeable plastic sheeting
D Gypsum board
Explanation: For low-slope roofs (2:12 to 4:12), self-adhering
underlayment (ice and water shield) is required as a secondary barrier
against wind-driven rain and ice dams.
,3
What is the maximum allowable spacing for nails on asphalt shingles
per the Illinois State Plumbing and Roofing Code?
A 6 inches on center
B 12 inches on center
C 4 inches on center
D 8 inches on center (Correct)
Explanation: Standard code requires nails to be spaced no more than 8
inches apart and no less than 2 inches from shingle edges to prevent
lifting.
4
When installing ice and water shield on an Illinois home, how far must it
extend from the interior wall line?
A 12 inches
B 36 inches (Correct)
C 18 inches
D 24 inches
Explanation: Ice and water shield must extend at least 36 inches from
the interior warm wall line to prevent ice dam leakage in Illinois climate.
5
Which of the following fasteners is prohibited for attaching metal roof
panels in Illinois?
A Galvanized roofing nails
B Stainless steel screws
C Electroplated smooth shank nails (Correct)
D Polypropylene coated screws
Explanation: Electroplated nails lack corrosion resistance and are not
approved for metal roofing due to rust risk under thermal cycling.
,6
What is the minimum headlap for double-coverage asphalt shingles?
A 8 inches
B 10 inches
C 12 inches (Correct)
D 6 inches
Explanation: Double-coverage shingles require a 12-inch headlap to
ensure two layers of material cover the roof deck at any point.
7
A roofer in Illinois must register with which state agency before
performing work over $1,000?
A Illinois Department of Transportation
B Illinois Department of Financial and Professional Regulation (Correct)
C Illinois Roofing Association
D Illinois Attorney General
Explanation: Roofing contractors must register as a roofing contractor
with IDFPR under the Illinois Roofing Industry Licensing Act.
8
What type of vent is required for attics with asphalt shingles to prevent
condensation?
A Ridge vent with continuous soffit intake (Correct)
B Gable vent only
C Turbine vent without soffit
D Powered fan only
Explanation: Balanced ventilation (ridge + soffit) is required to maintain
airflow and prevent moisture buildup under shingles.
, 9
What is the minimum thickness for plywood roof decking under asphalt
shingles in Illinois?
A 7/16 inch (Correct)
B 1/2 inch
C 3/8 inch
D 5/8 inch
Explanation: 7/16 inch OSB or plywood is the minimum accepted by
code for standard shingle installation.
10
Which underlayment is acceptable for use under clay tile roofs in
Illinois?
A 60-minute felt paper (Correct)
B 15-pound felt
C Plastic vapor barrier
D Single-ply EPDM
Explanation: Clay tile requires a 60-minute or heavier underlayment for
additional waterproofing due to tile porosity.
11
A roofing contractor in Illinois who fails to provide a written contract for
work over $1,000 is subject to what penalty?
A License suspension only
B No penalty if work quality is good
C Fine up to $10,000 and possible license revocation (Correct)
D Mandatory retraining
Explanation: IDFPR rules require written contracts for any roofing work
over $1,000; violation can lead to fines and license action.
