No modern building can function properly if the design program and construction detailing fails to account for the thermal and moisture dynamics of the building envelope and its relation to the internal and external environment. This class will be an in-depth building science investigation of hygrothermal issues, including steady-state heat loss, internal and external heat gains, wind & solar radiant impacts, temperature gradients within the building envelope and the effect of relative humidity, air convection and mean radiant temperature on human comfort. This will be the context to explore the often misunderstood issues around indoor and outdoor moisture, moisture migration through the building envelope, moisture storage (or buffering) capacity of materials, effects of relative humidity within the thermal envelope and inside the building, and moisture control methods that minimize mold, rot, corrosion and warping while optimizing durability of the structure and human comfort.

Course start time: Saturday, 9am
Course end time: Sunday, 5pm

  • Competency Level: Intermediate to Professional
  • AIA credits: 14 HSW Learning Units
  • Sterling College credits: 1 Continuing Education Unit ($130 additional)


Course Objective

  • To understand and properly design for moisture and comfort.

Suggested/Required Reading

The more you bring with you, the more you will take away. However, you will also leave with a set of handouts covering all topics on the syllabus.

Materials/Tools to Bring

  • Scientific Calculator (required)
  • Notepad
  • Thinking Cap

Course Outline

Thermal Factors

  • exergy flux
  • insulation
  • infiltration
  • mass effects
  • internal gains
  • Solar effects
  • temperature gradients

Human Comfort Factors

  • temperature
  • relative humidity
  • convection
  • mean radiant temperature
  • indoor air quality

Hygric Factors

  • absolute humidity
  • relative humidity
  • specific humidity
  • mixing ratio
  • vapor pressure
  • dew point
  • sorption/desorption
  • moisture storage
  • moisture content
  • mold, rot, corrosion

Moisture Sources

  • environmental (rain, snow, outdoor relative humidity, wind & pressure differentials)
  • structural (bound water in materials, wetting from construction)
  • anthropogenic (respiration, bathing, cooking, washing)
  • other (plants, earth, leakage)
    • momentum
    • gravity
    • surface tension
    • capillary action
    • ab/adsorption
    • pressure differential
    • vapor differential
    • temperature differential
    • bulk water movement
    • water vapor diffusion
    • convective transport
    • condensation & freezing
    • gravity drainage
    • desorption
    • diffusion
    • evaporation
    • in air
    • in hygroscopic materials
    • liquid pooling
    • exposure reduction
    • deflection
    • shedding
    • water resistance
    • moisture tolerance
    • drying potential
    • air sealing
    • diffusion retarders
    • thermal control
    • pressure control
    • humidity control
    • ventilation (dilution)
    • sealed face
    • redundant barrier
    • drainscreen
    • rainscreen
    • hermetic house
    • breathable envelope
  • Moisture Infusion Mechanisms

    Moisture Elimination Mechanisms

    Moisture Storage

    Moisture Control Techniques

    Rain Control Techniques

    Moisture Control Strategies


Start Date: March 8, 2014