Insulation Flashcards
What are typical R values for floor, walls, attic space?
Attic: R-25-40
Walls: R12-R20
Floors over unheated spaces: R20-R30
What Direction does thermal energy flow?
High energy to low energy
What does an air barrier do?
It prevents or restricts air leakage/movement
What is a vapor barrier?
It’s designed to restrict the movement of water vapor and restricts both vapor diffusion and air leakage
prevents vapor diffusion - must be on the warm side
On one side only
What is the purpose of insulation
To slow the rate of heat transfer\
What are the forms of insulation
Loose Fill
batts or blankets
rigid boards
foamed in place
What are the two types of Foamed in Place insulation
polyurethane
polyiscyanate
what are typical air barriers
Think system
windows, drywall, plaster, doors, caulking, weatherstripping
polyethylene film
what are the 4 common types of roof vents
Soffit
Ridge
roof
gable
what are the rec. amounts of attic ventilation
total vent area = 1/300 of the floor space of the attic.(divide sq foot by 300)
Ex. if attic is 600 sq ft, you want 2 square feet of free vent area (must take in account obstructions like louvers and screens.
If roof slope lower the 2:12 or cathedral roof increase vent are to 1/150 of the roof area (twice the normal square feet)
What if no attic, how do you vent?
ventilate by maintaining 2 1/2 inch between top of insulation and underside of roof sheathing
Can you have to much venting?
Yes, it can create a negative air pressure in the roof
How far do you go on an attic inspection
if attic insulation completely covers the ceiling joists, do not walk through the attic.
Describe in detail how you performed your attic inspection.
common Access hatch problems
not insulated
missing or inaccessible
What are the most common types of Rot
Brown and White Rot
Brown rot is most common on softwoods
White rot is most common on Hardwoods
How do you identify Rot
Early stages, wood surface becomes dull and discolored, often musty smell.
As the rot advances, wood becomes spongy and crumbly
How do you avoid rot
Keep the moisture content below 20%
What is the likely cause of localized staining or dampness on ceiling finish?
Roof Leak
What is the likely cause of widespread staining or dampness on ceiling finish?
Likely culprit is condensation
What are the most likely implications of missing or incomplete barriers
Risk of mold and rot owing to air leakage into the roof space
What is the recommended advise to clients with flat and cathedral roofs
They are prone to concealed damage from rot and mold. Without destructive testing, its impossible to know whether there is a serious problem. Most of your comments are based on indirect evidence
Is missing wall insulation in a basement a problem
No. Adding insulation in a basement is an improvement
What is the typical crawlspace ventilation ratio?
One sq. ft for every 150 square feet of crawlspace floor. (Same as a low pitched attic)
Should you enter a crawlspace?
If it is safe, you should enter and inspect.
a. do not enter if it has standing water that could be stagnant
b. if you can identify animals in the crawlspace or animal waste, be careful and consider there to be a potential hazard to your health
Should a crawlspace with a moisture barrier, be ventilated?
No.
If a crawlspace does not have a moisture barrier, what should the recommendation be?
- Make sure there is adequate ventilation
- Recommend that it be added to help prevent excessive moisture and potential mold and rot
Should embedded joists (in Concrete) be insulated?
No, but caulking of the joints is ok.
Should insulation in basements, crawlspaces and Garages or any other interior space that has access to people, electricity and heating source be left open?
No, it should be covered with drywall or other interior finishes
The primary function of insulation is to
reduce heat loss in winter and heat gain in summer, leading to more comfortable indoor temperatures and lower energy costs
to A vapor retarder Is designed to?
Restrict vapor diffusion
Vapor diffusion is the movement of water vapor molecules through porous materials, driven by differences in vapor pressure, like in building materials or when growing crystals in a lab
List three common problems found with flat roof insulation systems
- Wet, Compressed or voids
- Missing or incomplete air/vapor barrier
- Missing or inadequate venting
What should you wear when inspecting attics
Mask, goggles, long sleeves with tight cuffs
Where should the air slash vapor barrier be located in a wall assembly in a hot humid climate
Warm part of the wall
Should all crawl spaces be vented
no
What are three things that make attics dangerous
Falling through the ceiling, electric shock, irritate lung’s eyes and skin
List four areas where floors over unheated spaces are difficult to inspect
Above garages, above porches, in cantilevered areas, bathroom
List three functions of roof vents
Allow warm moist air out of the attic, reduce attic temperature in summer and helps prevent ice dams in winter by keeping attic cold
Name two purposes of house ventilation
Flushes moisture from unconditioned spaces and winter and heat from these spaces in summer, and provides fresh air for building occupants
Describe one possible way to get a look at insulation in the flat roof
Remove ceiling light fixture or exhaust fan covers or pop fascia vents off and look through holes
Define relative humidity
Amount of moisture in the air relative to the amount it could hold if saturated
Is it more important for the air barrier or vapor barrier to be continuous
Air barrier
