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

Straw bale walls typically achieve R-30 to R-50 for a full bale wall, far exceeding the insulating performance of dense earthen materials like cob, adobe, or rammed earth.

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

Limecrete uses hydraulic lime as the binder instead of Portland cement, creating a breathable, lower-carbon structural material well-suited for natural building floors and foundation slabs.

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

Routing greywater to irrigate trees means the waste management system simultaneously handles disposal and irrigates plants, demonstrating that each element should perform multiple functions.

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

Earthships use discarded automobile tires packed tightly with rammed earth as their primary structural wall, and often integrate rainwater catchment, greywater treatment, and food production systems.

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

Vapor-permeable or 'breathable' materials allow moisture vapor to diffuse through the wall assembly, preventing trapped moisture that leads to mold growth and structural decay.

(PDC) Permaculture Design Certification Practice Test

(PDC) Permaculture Design Certification Practice Test

PDC Natural Building & Shelter Design 3