PDC Natural Building & Shelter Design 1 — Questions and Answers
Question 1: What is the primary principle behind passive solar design in natural building?
- Positioning windows to maximize year-round sunlight regardless of direction
- Using the sun's energy for heating and cooling without mechanical systems (Correct answer)
- Installing solar panels to generate electricity for the building
- Painting walls dark colors to absorb maximum heat
Correct answer: Using the sun's energy for heating and cooling without mechanical systems
Passive solar design harnesses the sun's energy for heating, cooling, and lighting without relying on active mechanical systems.
Question 2: Which natural building material is made by mixing subsoil clay, sand, straw, and water, then shaped into walls by hand?
- Adobe
- Rammed earth
- Cob (Correct answer)
- Cordwood
Correct answer: Cob
Cob is a monolithic natural building material made by mixing subsoil, sand, straw, and water, then sculpted by hand into continuous solid wall structures.
Question 3: What does 'thermal mass' refer to in the context of natural building?
- The weight-bearing capacity of a wall structure
- The insulating value of a material measured in R-value
- A material's ability to absorb, store, and slowly release heat (Correct answer)
- The ratio of solar energy reflected by a surface
Correct answer: A material's ability to absorb, store, and slowly release heat
Thermal mass refers to the ability of a dense material (such as stone, earth, or concrete) to absorb heat during the day and slowly release it at night, moderating indoor temperature swings.
Question 4: Which climate type is cob construction BEST suited for?
- Hot and humid tropical climates
- Cold subarctic climates with extreme snowfall
- Temperate climates with low to moderate rainfall (Correct answer)
- Coastal climates with high salt air exposure
Correct answer: Temperate climates with low to moderate rainfall
Cob performs best in temperate, relatively dry climates because it is susceptible to erosion from heavy rain and can absorb damaging moisture in very humid conditions.
Question 5: What does the R-value measure in building construction?
- The structural load capacity of a material
- The thermal resistance or insulating ability of a material (Correct answer)
- The compressive strength of earthen walls
- The water absorption rate of building materials
Correct answer: The thermal resistance or insulating ability of a material
R-value measures the thermal resistance of a material — the higher the R-value, the better the material resists heat flow and performs as insulation.
Question 6: What type of roof feature is especially critical in straw bale construction to protect the walls?
- A flat or low-slope roof to reduce wind exposure
- A large, wide overhang to protect walls from rain and ground splashback (Correct answer)
- A metal standing-seam roof to reflect solar radiation
- A butterfly roof to maximize rainwater collection
Correct answer: A large, wide overhang to protect walls from rain and ground splashback
Straw bale walls must be protected from moisture, so generously wide roof overhangs are critical to prevent rain and ground splashback from wetting and degrading the bales.
Question 7: What is the primary ecological benefit of a living roof (green roof) on a natural building?
- It generates solar electricity through photovoltaic cells integrated into the vegetation layer
- It provides insulation, manages stormwater runoff, and supports biodiversity (Correct answer)
- It completely eliminates the need for any other form of roof waterproofing
- It replaces the need for gutters and downspouts on any building
Correct answer: It provides insulation, manages stormwater runoff, and supports biodiversity
Living roofs provide insulation, absorb stormwater runoff, reduce the urban heat island effect, and create habitat supporting plant and insect biodiversity.
PDC Natural Building & Shelter Design 1
What is the primary principle behind passive solar design in natural building?