Ch. 5 - Insulation & Ventilation

Question 1

The primary function of insulation is to______

Answer 1

Control heat loss

Question 2

The vapor retarder is designed to ______

Answer 2

Restrict vapor diffusion

Question 3

What are the implications of an inadequate air/vapor barrier?

Answer 3

Moisture may get into the building, causing damage.

Question 4

Name 2 purposes of house ventilation

Answer 4

1. Flushes moisture from unconditioned spaces in winter and heat from these spaces in summer
2. Provides fresh air for building components

Question 5

Define relative humidity.

Answer 5

The amount of moisture in the air relative to the amount it could hold if saturated.

Question 6

What is meant by drying potential?

Answer 6

The ability of a material to dry out after it has gotten wet

Question 7

Why are roofs vented in the winter in cold climates?

Answer 7

We are not able to completely stop air leakage into cool roof spaces, she we need to get rid of that warm moist air.

Question 8

What is the purpose of a heat recovery ventilator?

Answer 8

To transfer some of the heat from the air exhausted from the house into fresh air coming into the house.

Question 9

The term ventilation might mean two very different things with respect to homes. Explain the 2 different types of ventilation.

Answer 9

1. Venting of roof and wall spaces to flush warm moist air out of the building components
2. Exhausting stale air and supplying fresh air to the living spaces

Question 10

Indicate where the air/vapor barrier should be located in the wall assembly in a hot, humid climate.

Answer 10

Outer part of the wall. Or none at all

Question 11

List 4 common forms that insulation materials may be found in

Answer 11

1. Loose fill
2. Batts or blankets
3. Rigid board
4. Foamed in place

Question 12

List 10 common insulation materials and the form they come in

Answer 12

1. Fiberglass - loose, batt, fill, board
2. Cellulose fiber - loose fill
3. Mineral wool- loose fill, batt, board
4. Vermiculite- loose fill
5. Expand polystyrene (eps) - board
6. Extruded polystyrene- board
7. Closed cell phenolic plastic - board
8. Polyisocyanurate - board
9. Polyurethane - foamed in place
10. Iscoyanate- foamed in place

Question 13

What is the function of an air barrier?

Answer 13

To stop air movement though building walls and roof

Question 14

Indicate two reasons we are interested in controlling air movement through building walls and roofs?

Answer 14

1. Minimize heat flow to exterior/interior

2. Minimize moisture flow to building components

Question 15

Describe the function of a vapor barrier

Answer 15

To protect the building from moisture damage. Designed to protect from moisture due to vapor diffusion, not air movement

Question 16

List two other names for vapor barriers

Answer 16

Vapor retarder

Vapor diffusion retarder vdr

Question 17

Is it important for the air barrier or vapor barrier to be continuous

Answer 17

Air barrier

Question 18

Should the vapor barrier be on the warm side or cold side of the wall assembly

Answer 18

Warm side

Question 19

Should the vapor barrier be on the warm side or cold side of the wall assembly in a hot, humid climate

Answer 19

Warm side

Question 20

List 3 functions of roof vents

Answer 20

Allow warm moist air out of the attic
Reduce attic temperatures in summer
Helps prevents ice dams in the winter by keeping attic cold

Question 21

List four types of roof vents

Answer 21

Soffit
Roof
Ridge
End gable

Question 22

What percentage of the total venting should be at the soffits

Answer 22

50%

Question 23

What percentage of the total venting should be high on the roof

Answer 23

50%

Question 24

When can soffit venting be omitted safely

Answer 24

If there are gable vents on opposing ends

Question 25

What do soffit vent baffles do

Answer 25

Prevents insulation from covering the vents

Question 26

How are mansard or gambrel roofs ideally center

Answer 26

Required at ridge and bottom of upper section | None is required doe the steep section

Question 27

Is it possible to over ventilate an attic. If so why is it an issue

Answer 27

Yes if ceiling is not well sealed | Can cause negative pressure in the attic that promotes warm moist air to enter at a faster rate

Question 28

List three things that make attics dangerous

Answer 28

Fall through the ceiling Latrice shock Irritate lungs, eyes, skin

Question 29

List four common hatch problems and the implications of each

Answer 29

Not insulated - heat loss Not weather stripped - heat loss and air leakage Missing - heat loss and air leakage Inaccessible - limits inspection

Question 30

What are the implications of insulation that is only 1. two Inches thick, 2. wet, 3. compressed, 4. interrupted by gaps or voids or 5. missing

Answer 30

1. Heat loss 2. Not work well, damages finishes 3. Reduce r value 4. Localized heat loss, ice dammin 5. Heat loss, ice damming

Question 31

Under what circumstances should insulation cover Reese's lights. What is one inspection strategy to help I'd recessed lights while in the attic.

Answer 31

Only if lights are the proper type or installed in drywall boxes Look for double she'll, or IC stamp

Question 32

Will you ever see walls in attics. Where. Should these be insulated?

Answer 32

Walls indicate skylights or light wells. Yes, should be insulated

Question 33

What two things should you be looking for on ducts in attics

Answer 33

Insulation | Air/vapor barrier

Question 34

How should insulation be handled around masonry chimneys

Answer 34

Should not have combustible insulation surrounding them

Question 35

How should insulation be handled around metal vents

Answer 35

Vent is contained in a boxed in area to keep insulation away

Question 36

What are the implications of air/vapor barriers that are missing or incomplete

Answer 36

Air leakage Rot damage Insulation gets wet from condensation

Question 37

List three common problems with roof vents and their implications.

Answer 37

Problems: birds nests, mech damage, undersized openings Implications: inadequate venting, mold or rot from condensation

Question 38

What is suggested by snow on attic insulation below roof vents

Answer 38

If soffit venting is missing, rain and snow may actually be drawn into the roof vents

Question 39

Listen three possible concerns with turbine vents

Answer 39

No ventilation on calm days Too much ventilation on windy days Noisy or seized

Question 40

Should power vents be operating in the winter. Why or why not

Answer 40

No, because it could unnecessarily pull heat air out increasing the heating loss

Question 41

What is suggested by mold or rot on rafters or sheathing

Answer 41

An exhaust fan dumping warm moist air directly into the attic

Question 42

Describe in one sentence each four general approaches to insulating flat and cathedral roofs

Answer 42

1. Treat as an attic with little insulation sand an air space 2. Completely fill roof space, in theory it stops airflow 3. Insulate above sheathing, roof membrane apps piled over insulation 4. Insulate below roof structure, lowers exiling heights, but provides good ventilation

Question 43

List five common problems found with flat roof insulation systems and the implications of each

Answer 43

1. Too little insulation - heat loss, no damage to structure 2. Wet, compressed or voids - reduced r valid, mold mildew rot 3. Missing or incomplete air/ vapor barrier - mold mildew rot 4. Missing or inadequate venting - warm, moist air condensing and causing mold mildew rot 5. Venting obstructed - mold mildew rot

Question 44

Describe one possible way to get a look at insulation in a flat roof

Answer 44

Remove exiling light fixture or exhaust fan covers or pop fascia vents off and look through holes

Question 45

What things might suggest wet insulation

Answer 45

Staining, sponginess or dampness on ceilings

Question 46

Describe two strategies used to deal with venting of flat roofs

Answer 46

Vent the roof space | Seal the roof cavity

Question 47

On a flat roof where will you most often see the vents

Answer 47

Opposing casitas

Question 48

What is an appropriate ratio of vent area to roof area

Answer 48

One sf of venting for every 150 sf of roof area

Question 49

T or f Basement wall insulation is necessary

Answer 49

False

Question 50

Two strategies to insulate basement walls

Answer 50

Outside - keeps walls warm, no interior space lost, but only certain types can be used Inside - inexpensive, can be done at anytime, any type but can be difficult to detect leaks

Question 51

Two general approaches to insulating crawl spaces

Answer 51

Insulate walls rearing conditioned crawlspace | Insulate floors above creating unconditioned space

Question 52

T or f all crawlspace a should be vented

Answer 52

True if I heated vented to outdoors to remove warm moist air in cold climates

Question 53

List nine common problems with insulation and ventilation in basement and crawl spaces

Answer 53

``` Insulation too little or incomplete Exterior insulation it suit able for below grade use Ext insulation not protected at top Insulation missing at rim joists Insulation saggin, loose or voids Exposed combustible insulation Air/ vapor barrier missing incomplete or wrong location No moisture barrier on basement walls No moisture barrier on earth floor ```