ICA Module 2 Section 4 Venting/Insulation Flashcards
The primary function of insulation is to ____
slow rate of heat loss in house
A vapor retarder is designed to _____
restrict movement of water vapor
What are the implications of an inadequate air/vapor barrier?
mold, rot
Name 2 purposes of house ventilation:
remove moisture, keep air fresh from pollutants
Define relative humidity
the amount of moisture in the air relative to the amount of moisture air could hold if saturated
What is meant by drying potential?
how good air flow (ventilation) is to dry out
Why are roofs vented in the winter in cold climates?
keep moisture out, prevent ice dams
What is the purpose of a heat-recovery ventilator?
extract stale, moist air from wet rooms & supply fresh, filtered air
The term ventilation might mean two very different things with respect to homes. Explain the two different types of ventilation.
living spaces, unconditioned spaces
Indicate where the air/vapor barrier should be located in the wall assembly in a hot, humid climate.
warms state
List 4 common forms that insulation materials may be found in.
loose fill, bat, board, foamed in place
List 10 common insulation materials. (Vermiculite & perlite only count as 1. There are 2 types of polystyrene)
fiberglass, cellulose fiber, mineral wool, perlite, expanded polystyrene, extruded polystyrene
What forms do these materials come in?
?
What is the function of an air barrier?
stop air movement
Indicate 2 reasons we are interested in controlling air movement through building walls & roofs.
air carriers, heat & moisture
Describe the function of a vapor barrier.
protect house from moisture damage
List 2 other names for vapor barriers
vapor retarder, vapor diffusion retarder
Is it more important for the air barrier or the 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
List 3 functions of roof vents
remove moisture, replace stale air,
List 4 types of roof vents
soffit, ridge, roof, gable
What % of the total venting should be at the soffits?
50%
What % of the total venting should be high on the roof?
50%
When can soffit venting be omitted safely?
when there are gable vents at each end of attic
What do soffit vent baffles do?
prevent insulation from blocking soffit vent
How are mansard or gambrel roofs ideally vented?
ridge & bottom of upper section
Is it possible to over ventilate an attic? If so, why is this an issue?
yes, it draws warm/moist air from living space
What things should you wear when inspecting an attic? (3 things)
mask, goggles, gloves
List 3 things that may make attics dangerous.
insulation covering joists, weak stair, poor lighting
What are the implications of insulation that is only 2” thick, wet, compressed, interrupted by gaps or voids, or missing?
screwed shut, nailed shut, painted shut,
List 4 common access hatch problems & the implications of each.
poorly insulated
Will you ever see walls in attics? Where? Should these be insulated?
yes, towards bottom of roof (knee wall), yes
Under what circumstances should insulation cover recessed lights? What is one inspection strategy to help identify recessed lights while in the attic?
double shell lights, look for shells on joists
What 2 things should you be looking for on ducts in attic?
disconnected, missing
How should insulation be handled around masonry chimneys?
non-combustible
How should insulation be handled around metal vents?
kept away
What are the implications of air/vapor barriers that are missing or incomplete?
air leakage causing condensation causing rot
List some common problems with roof vents & their implications
missing or inadequate moisture
What is suggested by snow on attic insulation below roof vents?
damaged vent
List 3 possible concerns with turbine vents
noisy, seized up, not venting on calm days (no wind)
Should power vents be operating in the winter? Why or why not?
no, they can increase heat less from house
What is suggested by mold or rot on rafters & sheathing?
poor ventilation/insulation
Describe in 1 sentence each, four general approaches to insulating flat & cathedral roofs.
treat as an attic (ventilate above insulation), completely fill roof space, isolate above roof structure & around perimeter, insulate below roof structure
List 5 common problems found with flat-roof insulation systems
air/vapor barrier missing, bad venting, mold, not enough insulation
For each of the problems found in flat roof insulation systems describe in 1 sentence the implications.
implications for air vapor barrier missing: mold/rot
Describe one possible way to get a look at insulation in a flat roof
vents in fascia boards
What things might suggest wet insulation?
staining, sponginess, or dampness on ceiling below
Describe 2 strategies used to deal with venting of flat roofs
??
On a flat roof, where will you most often see the vents?
soffit
What is an appropriate ratio of vent area to roof area?
1:150 (1 sqft venting every 150 sqft roof space)
Basement wall insulation is necessary. T/F
False
Describe in 2 sentences each, 2 strategies for insulating basement walls.
help with utility bill, keep moisture low
Describe in one sentence each, two general approaches to insulating crawlspace.
insulate walls, insulate floor above
All crawlspaces should be vented. T/F (Explain)
false, encapsulated doesn’t need vents
List 3 safety issues involved in inspecting crawlspaces.
stagnant water, animals, hatch less than 18” from bottom to top
List 9 common problems with insulation & ventilation in basement & crawlspace areas.
little, missing, loose
List the implications of each of the problems with insulation/ventilation in crawlspace & basements
implications for insulation/ventilation problems: moisture & rot
Describe 2 possible strategies for keeping floors over unheated spaces warm.
heat cavity between floor & insulation below, spray in place foam insulation
List 7 areas where floors over unheated spaces may feel cool.
above garage, above porch, cantilevered areas, over breezeways
