J1 - Building Science - LT #2

Question 1

Four basic functions of a building envelope:

Answer 1

Adds structural support to the building

Control Moisture and Humidity

Regulates Temperature

Controls Air Pressure Change

Question 2

What is radon?

Answer 2

Colorless, odorless, radioactive gas. Occurs naturally as a result of the decay of radium.

Question 3

What do UV rays damage?

Answer 3

Unprotected wood surfaces, the color of plastics, and metal finishes.

Question 4

Forces that affect building envelope below grade include:

Answer 4

Hydrostatic pressure

Frost Jacking

Adfreezing and Soil gas pressure

Question 5

Prevent frost heave by:

Answer 5

Place the foundation on well-draining soil so no water is underneath to freeze.

Protect to allow the heat of living space to heat the footing area and protect from freezing

Extend foundation below the frost level

Question 6

Adfreezing is:

Answer 6

Ice lensing, growth of ice crystals toward of a source of warmth. Can push against a foundation wall hard enough to crack it and lift a foundation.

Question 7

Roof drainage must be:

Answer 7

Closed pipe system that directs water to a public storm drain or to a drainage area on the low side of the building is desired.

Question 8

What is installed in the perimeter drain to prevent rainwater from backing up the perimeter drain?

Answer 8

Backflow prevention valve

Question 9

Backfill directly in contact with the building must be:

Answer 9

Grandular nature allows water to pass through it quickly into the perimeter drainage system.

Question 10

Drain rock should have:

Answer 10

Continuous covering of filter cloth. Cloth prevents the finer soils from settling into the drain rock, eventually restricting the flow of water to the drain.

Question 11

How do you prevent soil gas from entering the cracks of foundation walls or basement floor slabs?

Answer 11

AIr/moisture barrier is required below the basement slab.

Question 12

Heat gain causes what stress on buildings?

Answer 12

Material to expand, cold material to shrink. This movement puts stress.

Question 13

Wind can cause what issues?

Answer 13

Uplift and pressure differentials.

Question 14

The wind is proportional to the square of the speed.

Answer 14

As wind speed doubles, the force from wind increases four times. Triple and it is 9 times.

Question 15

Heating and cooling systems in a building must be designed to control:

Answer 15

Heat gain from the sun

Question 16

Prevailing winds create what two pressures?

Answer 16

Positive pressure on windward site and negative pressure on leeward side, this creates the draft and heat loss if building envelope not well sealed.

Question 17

If there is wind as well as rain or snow:

Answer 17

NEgative pressure in walls and attic draw the rainwater or snow into the building.

Question 18

What is the optimum comfort range of relative humidity?

Answer 18

30 to 50%

Question 19

Rats can fit through a hole what size?

Answer 19

1/2” in diameter

Question 20

Mice can fit through a hole of what size?

Answer 20

1/4” in diameter

Question 21

How do you prevent pest invasion?

Answer 21

Roof & vent openigns should have a heavy gauge metal mesh covering rather than nylon.

Gaps around plumbing and electrical should be stuffed with steel wool before being caulked to keep rats & mice out. Tight fitting sheet metal patches can be used to cover openings.