PDC Natural Building & Shelter Design 3

Question 1

Which natural building material typically achieves the highest insulation value (R-value) per inch of wall thickness?

Accepted Answer

Straw bale

Answer

Adobe earthen brick

Answer

Rammed earth

Answer

Cob

Question 2

In natural building, 'limecrete' refers to which material?

Accepted Answer

A flooring or structural material using hydraulic lime as a binder instead of Portland cement

Answer

A concrete substitute using volcanic ash (pozzolan) as the sole binder

Answer

A lime-based exterior plaster specifically formulated for straw bale walls

Answer

A mixture of lime and sawdust used as a poured insulation between floor joists

Question 3

Routing a building's greywater system to irrigate established trees downslope of the structure best demonstrates which permaculture principle?

Accepted Answer

Each element performs multiple functions

Answer

Use and value diversity

Answer

Catch and store energy

Answer

Obtain a yield

Question 4

Earthship buildings pioneered by architect Michael Reynolds are primarily characterized by which construction feature?

Accepted Answer

Used automobile tires rammed with earth as the primary structural wall element

Answer

Entirely underground earth-sheltered rooms with no above-grade exterior walls

Answer

Prefabricated natural material panels shipped flat-pack for on-site assembly

Answer

Floating pontoon foundations allowing the structure to adapt to rising groundwater

Question 5

What does 'vapor permeability' mean when describing natural building materials?

Accepted Answer

The material allows water vapor to diffuse through it, enabling walls to breathe and self-dry

Answer

The material is completely waterproof and prevents all forms of moisture movement

Answer

The material physically expands and contracts in direct response to changes in humidity

Answer

The material requires an impermeable vapor barrier on both interior and exterior surfaces

Question 6

Which plaster type is considered most compatible with straw bale walls due to its similar vapor permeability and slight flexibility?

Accepted Answer

Lime plaster

Answer

Portland cement stucco

Answer

Gypsum plaster board compound

Answer

Epoxy-modified polymer render

Question 7

A 'cold roof' design in natural building refers to a roof assembly that includes which key feature?

Accepted Answer

A ventilated air gap between the insulation layer and the roof deck to prevent ice dams and moisture buildup

Answer

Highly reflective white or silver surfaces to minimize solar heat gain in summer

Answer

A design specification for subarctic climates with snow loads exceeding 100 pounds per square foot

Answer

Phase-change materials that absorb heat in summer and release it only during cold weather