CLC Weatherproofing & Energy Efficiency 2 — Questions and Answers
Question 1: What is the recommended minimum R-value for attic insulation in a cold climate zone (Zone 5-8) per IECC standards?
- R-19
- R-30
- R-38
- R-49 (Correct answer)
Correct answer: R-49
IECC recommends R-49 minimum for attic insulation in climate zones 5-8 to meet energy efficiency requirements.
Question 2: Which type of window glazing provides the best solar heat gain control while maintaining visible light transmission?
- Double-pane clear glass
- Low-E coated glass (Correct answer)
- Tempered single-pane glass
- Reflective tinted glass
Correct answer: Low-E coated glass
Low-E (low emissivity) coatings selectively filter infrared radiation, reducing heat gain while allowing visible light through.
Question 3: A lead carpenter discovers a thermal bridge at a steel lintel above a window. What is the best corrective approach?
- Paint the lintel with reflective paint
- Add a continuous layer of rigid foam insulation over the lintel on the exterior (Correct answer)
- Wrap the lintel in fiberglass batt insulation
- Install weatherstripping along the lintel edges
Correct answer: Add a continuous layer of rigid foam insulation over the lintel on the exterior
Continuous rigid foam insulation on the exterior breaks the thermal bridge by preventing direct conductive heat transfer through the steel.
Question 4: What is the primary purpose of a house wrap (such as Tyvek) installed under siding?
- Provide primary thermal insulation
- Act as a vapor retarder on the warm side of the wall
- Serve as a water-resistive barrier while allowing vapor to escape (Correct answer)
- Replace the need for flashing at windows
Correct answer: Serve as a water-resistive barrier while allowing vapor to escape
House wrap is a water-resistive barrier (WRB) that blocks liquid water infiltration while remaining vapor-permeable to allow drying.
Question 5: When installing blown-in insulation in existing walls through drilled holes, what is the correct hole spacing typically used?
- Every 8 inches
- Every stud bay, about 16 or 24 inches on center (Correct answer)
- Every 4 feet
- Only at the top plate
Correct answer: Every stud bay, about 16 or 24 inches on center
Holes are drilled in each stud bay (typically 16" or 24" O.C.) to ensure every cavity is filled with blown-in insulation.
Question 6: What does SHGC stand for on a window energy label, and what does a lower value indicate?
- Standard Heat Gain Coefficient; lower means more heat is transmitted
- Solar Heat Gain Coefficient; lower means less solar heat enters the building (Correct answer)
- Seasonal Heat Generation Capacity; lower means poorer performance
- Structural Heat Guard Classification; lower means lighter glass
Correct answer: Solar Heat Gain Coefficient; lower means less solar heat enters the building
SHGC (Solar Heat Gain Coefficient) measures how much solar radiation passes through a window; a lower value means less heat gain.
Question 7: Which air sealing material is most appropriate for filling large irregular gaps around pipes and ducts penetrating the top plate?
- Fiberglass batt stuffed in the gap
- Closed-cell spray foam (Correct answer)
- Latex caulk
- Rope caulk
Correct answer: Closed-cell spray foam
Closed-cell spray foam expands to fill irregular voids and provides both air sealing and moisture resistance around penetrations.
CLC Weatherproofing & Energy Efficiency 2
What is the recommended minimum R-value for attic insulation in a cold climate zone (Zone 5-8) per IECC standards?