Module 2 Section 2 Insulation/Ventilation Study Cards Flashcards
The primary function of insulation is to__
control heat loss
A vapor retarder is designed to__
restrict vapor diffusion
What are the implications of an inadequate air/vapor barrier
moisture may get into the building structure, causing damage
Name 2 purposes of house ventilation
- flushes moisture from unconditioned spaces in winter & heat from these spaces in summer
- provides fresh air for building occupants
Relative humidity
the amount of moisture in the air relative to the amount it could hold if saturated, expressed as a percent
drying potential
ability of a material or assembly to dry out after it has gotten wet
Why are roofs vented in the winter in cold climates?
We were not able to completely to stop air leakage into cool roof spaces, so we need to get rid of that warm, moist air.
Purpose of a heat recovery ventilator:
To transfer some of the heat from the air exhausted from the house into the fresh air coming into the house
Term ventilation might mean 2 very different things with respect to homes. 2 different types of ventilation:
- venting of roof & wall spaces to flush warm moist air out of the building components
- exhausting stale air & supplying fresh air to the living spaces
Indicate where the air/vapor barrier should be located in the wall assembly in a hot, humid climate.
outer part of wall, or not at all
4 common forms that insulation materials may be found in:
- loose fill
- batts or blankets
- rigid boards
- foamed-in-place
10 common insulation materials:
- fiberglass 6. extruded polystyrene
- cellulose fiber 7. closed cell phenolic plastic
- mineral wool 8. polyisocyanurate
- vermiculite/perlite 9. polyurethane
- expanded polystyrene 10. isocyanate/polyisocyanate
What forms do insulation materials come in?
loose, fill, batt, board
loose fill
board
foamed in place
Function of an air barrier:
to stop air movement through building walls/roofs
Indicate 2 reasons we are interested in controlling air movement through building walls and roofs.
- minimize heat flow to exterior/interior
- minimize moisture flow to building components
Describe the function of a vapor barrier
protect building from moisture damage. designed to protect from moisture due to vapor diffusion, not air movement
2 other names for vapor barriers:
vapor retarder, vapor diffusion retarder
Is it more important for the air barrier or vapor barrier to be continuous?
air barrier
Should the vapor barrier be on the warm side or cold side of the wall assembly?
warm side
Should the vapor barrier be on the warm side or cold side of the wall assembly in a hot, humid climate?
warm side
3 functions of roof vents:
- allow warm, moist air out of attic
- reduce attic temps in summer
- helps prevent ice dams in winter by keeping attic cold
4 types of roof vents:
- soffit
- ridge
- roof
- gable
Percentage of total venting should be at soffits?
50%
Percentage of total venting should be high on roof?
50%