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Teacher
Edition Contents
Skill,
Tools, & Craftsmanship
Cutting
& Drying Fish
Sharpening
Nails,
Pegs, & Lashings
Falling
Trees &
Small-Scale
Logging
Guns
Chainsaw
Clutch & Chain
Ice
Pick
Shelters
Wood
Stoves
Wall
Tents
Steambaths
Insulation
& Vapor Barriers
Gas
Lamps & Gas Stoves
Travel
Piloting
A Boat
Boat
Design
Magnetos
& Spark Plugs
Carburetors
Compression
Outboard
Motor Lower Unit
Outboard
Motor Cooling System
Dogsleds
Snowmachine
Tracks
Snowmachine
Clutch
Snowshoes
Winter
Trails
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Activities
- While in a warm house, close the cover on a jar. Bring the jar
outside or put it in a freezer. Is there condensation inside the
jar when it is cooled? Bring the jar into the warm house again.
What happens?
Condensation will form when the jar is cooled (if there was
enough moisture in the air in the warm place before it was sealed.)
When the cold jar is brought into a warm place, condensation will
form on the outside of the jar for a while. Any condensation on
the inside of the jar will evaporate when it is fully warmed.
- Breathe on a plate or piece of metal that has been cooled outside
in sub zero temperatures. What happens. Bring it inside and watch
what happens. Where does the frost go?
It frosts on the cold plate, but evaporates in the warm building.
- The next time it gets –40° or –50°F, scuff
your feet on a rug and touch a doorknob (or your brother’s
ear). Is there a spark? Why do you think this doesn’t happen
when it is warm?
There is much static electricity during cold outside temperatures
as there is very little moisture in the air. During warm outside
temperatures, there is more moisture in the air, which “wicks
off’ the static electricity buildup, so there is less evidence.
- The next time it gets very cold, put a blanket against the
bottom of a cold window and leave it overnight. What happens?
Why?
The blanket freezes to the window. It insulates the cold widow
from the inside temperatures, and moisture from the room freezes
on the blanket.
- During cold weather, observe windows that are single, double,
and triple pane. What difference do you see?
Single pane frost terribly. Double pane frost a little. Triple
pane seldom frost.
- How are winter shoe packs with felt liners like a wall without
a vapor barrier? What happens in very cold weather when you try
to take the liners out of the boots after wearing them all day?
Why does this happen? Can you think of a way of preventing this?
The moisture from the person’s foot goes to the outside
of the felt liner and freezes against the inside of the rubber
shoe pack. They are frozen in. if you put your foot in a plastic
bag, and put that in the shoe pack, the moisture from your foot
couldn’t reach the liner. Your foot would be warm, but wouldn’
- Compare shoe packs with felt liners to the white “bunny”
boots or VB (vapor barrier) boots as they are called. What are
the similarities and differences?
They are similar in that they both have felt liners, and rubber
on the outside. They are different in that the VB boots have the
felt liner sealed off with a rubber vapor barrier on the inside.
The felt liner in the VB boots never gets wet because the moisture
of the foot cannot reach it. The felt liner in the shoe pack constantly
gets damp from the individual’s feet.
- Check the houses in the village. Ask what kind of insulation
is in the walls and ceiling. Is there a vapor barrier?
- Check the roof of an old abandoned cabin in your area. What
kind of insulation was in the walls and ceiling?
- Try to find an old abandoned log cabin with a sod roof. Study
the roofing materials.
- Test wet and dry insulation (wet & dry socks?) for their
conductivity of heat.
Damp socks transmit heat much faster than dry ones.
- Ask the oldtimers how they could detect a bear hole during winter
months. Does one of these signs relate to condensation?
The grass and branches around a bear hole will have condensation
from the moisutre in the hybernating bear’s breath. This
condensation is slight enough to be hard to detect.
- Put a glass tube or other piece of glass in a hot flame. Does
it conduct heat well? Compare this with a metal coat hanger or
other piece of long metal. Compare these with wood.
Wood and glass do not conduct heat well at all. Metal is a
good conductor.
- Visit a house under construction or talk to local carpenters.
Do you see the vapor barrier? What do the carpenters say about
vapor barriers?
- Ask oldtimers about sod roofs. Were they warm? Did they leak?
Sod roofs were very warm and cozy. They didn’t leak if
they were constructed properly. They had no vapor barrier, and
the moisture from the house passed though the sod. The sod roof
breathed the same way caribou mukluks breathe.
- Submerge a piece of closed cell foam (usually blue or pink)
after weighing it. Leave it under water for a few days. Weigh
it again. Did it absorb any water? What is the R factor of two
inches of foam?
Closed cell foam will not absorb water at all. It is excellent
for underground insulating. 2’ of foam has an R factor of
10.
Student Response
- What four things do the bacteria require that cause wood to
rot?
Wood, heat, moisture, air
- What is vapor?
Water in the air
- What would happen if there were no vapor in the air of our
homes?
We would have bloody noses and have a hard time breathing.
Wood would crack. There would be a great deal of static electricity.
- Which can hold more water vapor: warm or cold air?
Warm air
- What happens to the vapor in warm air when the air is cooled?
It will release the moisture that is held as a vapor
- What happens when vapor gets into the walls of our homes?
The air is cooled and it releases it’s moisture. This
ruins the insulation’s ability to retain heat. The moisture
also promotes rotting
- Draw a cross section of a wall that has insulation and a vapor
barrier.
- What things in our homes naturally put water vapor into the
air?
People’s breath, boiling water, and cooking.
- If you tried to explain the use of a vapor barrier simply to
someone who didn’t know, what simple rules would you give
them?
The vapor barrier must go between the living space and the
insulation. There should be no holes in the vapor barrier. The
vapor barrier and insulation work together. They should never
be used apart from each other in the north.
- What two things make fiberglass good insulation?
It doesn’t conduct heat and it traps dead air
- What are the three disadvantages of fiberglass insulation?
It is unpleasant to install. It is destroyed by floods and
little animals if they can remove it.
- What are two disadvantages of foam insulation?
High cost and it emits poisonous gasses when it burns.
- Draw a cross section of a sod roof. Did the oldtimers use a
vapor barrier?
No. The oldtimers didn’t use a vapor barrier. The sod
roof “breathed” allowing the vapor to pass through the
sod.
Math
- A roll of visquene is 8 x 100 feet. Assuming there are no overlaps
(in reality there are). How many rolls of visquene are necessary
to put a vapor barrier in a house 24’ x 36’, with walls
8’ high. The outside walls and ceiling need a vapor barrier.
How many square feet will be left over for overlap and other purposes?
Three rolls. 72 linear. ft. or 624 square feet left over.
- The above house needs _______ square feet of visquene. It comes
in rolls of 12’ x 100 for $47.21 or rolls of 8’ x 100’
for $29.52. What is the best combination of rolls that can be
purchased and what is the total cost?
The best combination is 1 roll of 12’ wide and 1 roll
of 8’ wide. Total cost is $76.73.
- Two inches of foam has an R factor of 10. Six inches of fiberglass
has an R factor of 19 (round off to 20). A piece of foam is 2’
x 8’ and costs $14. Fiberglass costs $37 for a roll that
contains 78 square feet. Which is the better insulation buy for
a square foot?
Foam is $.857 per square foot, giving an insulating value
of R10 or $1.75 per square foot of R 20 (2’ thick). Fiberglass
insulation is $.47 per square foot giving R 19. Fiberglass is
by far the cheaper insulation.
- A building has 1276 square feet to insulate with six inches
of fiberglass. The price of fiberglass landed on the jobsite is
$.47 per square foot. What is the cost of insulating the house?
$599.72
- Hank was building a 40’ x 56’ shop. He wanted to
pour the concrete floor over 4” of foam. Each piece of foam
is 2” x 2’ x 8’. How much would this cost if he
could get the foam for $10.99 each? (Round off if you like.)
$3077.20
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