GEORGIA VAPOR BARRIER INSPECTOR EXAM
QUESTIONS AND CORRECT ANSWERS
1. What is the primary purpose of a vapor barrier in a building
assembly?
A. Improve sound insulation
B. Reduce energy usage
C. Control moisture migration
D. Protect against UV exposure
Correct answer: C — Vapor barriers are installed to slow or stop
moisture vapor movement through building assemblies.
2. Which material is most commonly used as a vapor barrier in
residential construction?
A. Asphalt felt
B. Plywood
C. Polyethylene sheeting
D. Cement board
Correct answer: C — Polyethylene is widely used due to its low
permeability.
3. Vapor barrier effectiveness is measured by its:
A. Temperature rating
B. UV resistance
C. Perm rating
D. Fire resistance
Correct answer: C — The perm rating measures resistance to vapor
transmission.
4. A vapor retarder with a perm rating less than or equal to 0.1
perms is classified as:
A. Class I
B. Class II
C. Class III
D. Class IV
, Correct answer: A — Class I vapor retarders are 0.1 perms or less.
5. Which of the following is a Class I vapor barrier?
A. Kraft paper
B. 6-mil polyethylene
C. Latex paint
D. Unfaced insulation
Correct answer: B — Poly sheeting is a Class I vapor barrier.
6. Where should a vapor barrier typically be placed in a cold climate?
A. Exterior face of insulation
B. Interior/warm side of insulation
C. Middle of the wall assembly
D. On both sides of insulation
Correct answer: B — Prevents warm interior moisture from migrating
into cold spaces.
7. Installing vapor barriers on both sides of a wall can cause:
A. Fire hazards
B. Moisture trapping and mold growth
C. Noise issues
D. Structural instability
Correct answer: B — Two vapor barriers can trap moisture inside
assemblies.
8. The continuity of a vapor barrier is most often compromised by:
A. Paint
B. Concrete curing
C. Penetrations and unsealed seams
D. Insulation density
Correct answer: C — Holes and gaps significantly reduce effectiveness.
9. Which tape is recommended for sealing polyethylene vapor
barriers?
A. Duct tape
B. Masking tape
C. Cloth tape
, D. Acrylic-based vapor barrier tape
Correct answer: D — Acrylic tape maintains long-term adhesion.
10. A vapor barrier is required under concrete slabs primarily to
prevent:
A. Odor migration
B. Soil shifting
C. Moisture vapor movement from the ground
D. Cold temperatures
Correct answer: C — Vapor barriers beneath slabs stop ground moisture
migration.
11. Under-slab vapor barriers should be a minimum of:
A. 2 mils
B. 4 mils
C. 10–15 mils
D. 30 mils
Correct answer: C — Best practice for durability is 10 mil or greater.
12. A common failure point in under-slab vapor barrier
installations is:
A. Too many seams
B. Excess compaction
C. Punctures from construction traffic
D. Excess thickness
Correct answer: C — Walking, equipment, and rebar chairs often cause
punctures.
13. The term “vapor diffusion” refers to:
A. Water leaking through cracks
B. Air flowing through insulation
C. Moisture vapor moving through materials
D. Condensation forming on surfaces
Correct answer: C — Vapor diffusion is molecular moisture movement
through materials.
14. A vapor retarder with a perm rating between 0.1 and 1.0 is
QUESTIONS AND CORRECT ANSWERS
1. What is the primary purpose of a vapor barrier in a building
assembly?
A. Improve sound insulation
B. Reduce energy usage
C. Control moisture migration
D. Protect against UV exposure
Correct answer: C — Vapor barriers are installed to slow or stop
moisture vapor movement through building assemblies.
2. Which material is most commonly used as a vapor barrier in
residential construction?
A. Asphalt felt
B. Plywood
C. Polyethylene sheeting
D. Cement board
Correct answer: C — Polyethylene is widely used due to its low
permeability.
3. Vapor barrier effectiveness is measured by its:
A. Temperature rating
B. UV resistance
C. Perm rating
D. Fire resistance
Correct answer: C — The perm rating measures resistance to vapor
transmission.
4. A vapor retarder with a perm rating less than or equal to 0.1
perms is classified as:
A. Class I
B. Class II
C. Class III
D. Class IV
, Correct answer: A — Class I vapor retarders are 0.1 perms or less.
5. Which of the following is a Class I vapor barrier?
A. Kraft paper
B. 6-mil polyethylene
C. Latex paint
D. Unfaced insulation
Correct answer: B — Poly sheeting is a Class I vapor barrier.
6. Where should a vapor barrier typically be placed in a cold climate?
A. Exterior face of insulation
B. Interior/warm side of insulation
C. Middle of the wall assembly
D. On both sides of insulation
Correct answer: B — Prevents warm interior moisture from migrating
into cold spaces.
7. Installing vapor barriers on both sides of a wall can cause:
A. Fire hazards
B. Moisture trapping and mold growth
C. Noise issues
D. Structural instability
Correct answer: B — Two vapor barriers can trap moisture inside
assemblies.
8. The continuity of a vapor barrier is most often compromised by:
A. Paint
B. Concrete curing
C. Penetrations and unsealed seams
D. Insulation density
Correct answer: C — Holes and gaps significantly reduce effectiveness.
9. Which tape is recommended for sealing polyethylene vapor
barriers?
A. Duct tape
B. Masking tape
C. Cloth tape
, D. Acrylic-based vapor barrier tape
Correct answer: D — Acrylic tape maintains long-term adhesion.
10. A vapor barrier is required under concrete slabs primarily to
prevent:
A. Odor migration
B. Soil shifting
C. Moisture vapor movement from the ground
D. Cold temperatures
Correct answer: C — Vapor barriers beneath slabs stop ground moisture
migration.
11. Under-slab vapor barriers should be a minimum of:
A. 2 mils
B. 4 mils
C. 10–15 mils
D. 30 mils
Correct answer: C — Best practice for durability is 10 mil or greater.
12. A common failure point in under-slab vapor barrier
installations is:
A. Too many seams
B. Excess compaction
C. Punctures from construction traffic
D. Excess thickness
Correct answer: C — Walking, equipment, and rebar chairs often cause
punctures.
13. The term “vapor diffusion” refers to:
A. Water leaking through cracks
B. Air flowing through insulation
C. Moisture vapor moving through materials
D. Condensation forming on surfaces
Correct answer: C — Vapor diffusion is molecular moisture movement
through materials.
14. A vapor retarder with a perm rating between 0.1 and 1.0 is
