· Mortar problems in masonry chimneys are the cause of more fires
than any other fireplace or chimney problem.
· The auto-ignition temperature for wood is 450° F.
· Creosote build up in chimneys results from burning wet wood,
insufficient air for combustion and lazy slow burning fires. Creosote can be
shiny black or dark brown fluffy, flaky material. At room temperature it is
hard but when hot, the creosote becomes a liquid and flows. It is extremely
combustible and is a major cause of chimney fires. Burn hard wood rather than
soft wood. Use dry seasoned wood rather than green or wet wood. Provide adequate
of combustion air. Do not burn driftwood, painted or pressure treated wood.
Do not burn magazines, newspapers, plastic or garbage. Fires that burn hot are
· A masonry fireplace built at grade with a 20 foot high chimney
will weigh roughly 12 tons. Assuming the fireplace is about 3 1/2 feet deep
and 6 feet wide. This will exert a pressure of 1000 PSF (pounds per square foot)
on the soil.
· Burning natural gas primarily gives off water and carbon dioxide.
One of the products of incomplete combustion is carbon monoxide, which is poisonous.
Natural gas is especially dangerous because it is colorless, odorless and highly
combustible. Since natural gas is lighter than air it tends to rise and dilute
· Propane is heavier than air and will accumulate in low spots
creating a dangerous situation.
· At normal atmospheric temperature and pressure, natural gas
is a vapor, not a liquid.
· Natural gas is perfumed so you can smell a leak.
· The most common item to fail on a high-efficiency furnace are
the induced-draft fans.
· Water often gets into oil tanks from condensation. Water is
heavier than oil, settling to the bottom of the tank. Over time it reacts with
the sulfur in the oil, making a mild sulfuric acid, rusting out the tank.
· The life of a buried oil tank is 10 - 20 years after that it
is an environmental concern. Contamination of soil resulting from oil leaks
can be very expensive to clean up.
· One BTU is roughly the heat given off by a match.
· One BTU is the amount of heat required to raise one pound of
water one Fahrenheit degree.
· One cubic foot of natural gas contains about 1000 BTUs.
· One cubic foot of propane contains about 2500 BTUs.|
· One gallon of heating oil contains about 140,000 BTUs.
· One cubic foot of dried, split, stacked firewood can contain
anywhere between 100,000 and 225,000 BTUs.
· Hot water boilers for heating the home should never have their
water changed, it is best to keep the water inert. The chemicals in new water
will accelerate the corrosion.
· Electric heating systems are designed to deliver 5 - 8 watts
of heat per square foot of living space.
· Typical residential furnace blower has a static pressure (push
on the air it moves) equal to 1/56th inch of a psi. Dirt on the blades can dramatically
reduce its capacity, comfort and increase heating costs. It can also overheat
and shorten the life of a heat exchanger (heart of the furnace or most expensive
· Bigger the heating duct size the better. Round ducts are the
best, then square, further from square the worst it gets for air flow. The longer
the duct the more resistance to air flow. Corners are killers. Standard round
elbow is equal to 10 linear feet of round in terms of pressure loss. Flex duct
will have 3 times the pressure loss of rigid because of its corrugated walls.
Blower speed and blade profile influences the amount of airflow. Furnace location
is paramount, center of building is best.
· Adding extras to duct systems such as air conditioning can half
the blower pressure because of the evaporator coil located in the furnace supply
duct plenum. Electronic air cleaner can reduce blower pressure by 20% again
because it is located in the furnace supply duct plenum. These are large pressure
losses, that if not designed in originally can seriously effect the efficiency
of a heating system.
· Water left sitting in humidifiers in the off season can be breeding
grounds for bacteria because of the warm, wet environment. This can be a health
· Residential construction live floor loads are deigned for 40
pounds per square foot.
· An earthquake over 7.5 on the Richter scale is a major earthquake.
House failure modes during a quake include posts moving off piers, beams moving
off posts, cripple or pony walls moving off foundations. This is why it is important
for sill plate anchors and hold downs to have their washers and nuts on. Post
saddles, joists hangers, hurricane clips and straps fully nailed. Hot water
tanks secured. Gas valves that shut off automatically if a line ruptures. And
shear walls that help resist strong lateral forces during an earthquake or hurricane.
· Hot tap water should not be used for drinking or cooking because
hot water leaches lead from pipes and solder joints.
· Cross connections are a possibility wherever the supply plumbing
and solid or liquid waste could come together. A cross connection is a serious
health issue. There is a risk of illness or death if the potable water for drinking,
cooking and washing is contaminated with waste. 1. Fixtures where the faucet
spout is below the overflow or flood rim of the fixture. This occurs on older
bathtubs and laundry tubs, for example. 2. Fixtures where handheld showers,
extendable faucets or vegetable sprayers can be left in tubs, basins or sinks.
3. Garden hoses left attached to a hose bibb. 4. A toilet tank where the fill
water enters at the bottom. 5. A dishwasher where a solenoid valve separates
the clean water from the gray water (a term used to describe water that is no
longer clean but does not include human waste). 6. A clothes washing machine
with a discharge pipe in a laundry tub. 7. A water softener. 8. A humidifier
connected to the supply plumbing system. 9. A lawn or fire sprinkler system.
10. A bidet where water enters the bowl at the bottom. 11. A hot water boiler
(boilers are connected to the supply plumbing piping so that make up water can
be provided to the boiler). 12. A swimming pool fill outlet that is located
below the flood level of the pool. 13. A trap primer without an air gap. We
have to prevent the waste water from getting back into the supply water. Cross
connections are caused by the arrangement of plumbing fixtures. It can be the
design of the fixture itself or the way it's installed. The health implications
are serious if cross connections exist.
· Many supply water fixtures have backflow prevention devices to stop
potable water from becoming contaminated. Every outlet in the water distribution
system should have either an air gap or a backflow prevention device of some
· Rot is the biggest enemy of wood. Air, moisture content greater than
20% and temperature between 40° F and 115° F is the perfect conditions
for rot to exist. Wood under water will not rot. Dry wood will not rot. Reducing
moisture levels is the best way to control it.
· Sunlight does not dry wood the way most people assume. Yes the sun
evaporates water but in wood it drives the water into the material and all the
way through, hopefully. The importance of the drying potential (air movement),
on the back of wood siding is important.
· There are some wood siding buildings in North America that have lasted
more than 300 years with out any finish. Quality of wood and installation is
a factor to achieve this kind of performance.
· Paints and varnishes are surface finishes, while stains and preservatives
are penetrating finishes. Peeling paint is often due to poor surface preparation
or different expansion and contraction properties. Blistering is usually caused
by to much moisture in the wood or paint drying to fast when applied. Some wood
like cedar have natural resins that resist rot. Any wood product will rot if
the moisture content is consistently above 20% and temperatures are between
40° F to 115° F range. Fungus or mildew at edges indicate high moisture
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· Roofing terminology - one square is a 100 square foot area (10 feet
X 10 feet) of roofing material installed with its intended exposure. 3 bundles
of asphalt shingles = 1 square. 4 bundles of wood shakes or shingles = 1 square.
· One of the oldest wood roofs on record was a house built in 1794.
The roof lasted for more than 130 years. The shingles were white oak held in
place with hand forged iron nails.
· Clay tile roofs have a life expectancy up to 350 years. They have
been used since the days of Greek and Roman empires in Europe. Arguably the
best steep roofing material available.
· There is a church in England with a 1200 year old slate roof.
· Copper the "Cadillac" of metal roofing can last over 100
· Improper attic ventilation can cause condensation where the warm house
air meets the cool attic air. Wet insulation will lose it's insulating ability,
wet wood will eventually rot the roof structure. Exposure to high attic heat
from lack of ventilation over a long period of time can cause asphalt shingles
to blister, buckle and shorten their life expectancy.
· Mold, mildew and rot are all fungi. Fungi grow from spores or seeds
released by mushrooms. These spores are present in the air everywhere. When
these spores settle on surfaces that favor growth, they will establish small
filaments called hyphae. These hyphae release enzymes that break down the organic
matter to become food. Oxygen, temperature, moisture and food (wood) are the
necessary elements for growth. It is the condensation in crawlspaces, walls
and roofs that is the danger.
· Spalled (flaking or crumbling) concrete surface can be caused by using
salt for deicing. Salts are harder on concrete since they crystallize and expand
below the surface, causing spalling. Many recommend urea-based deicing agents
rather than salts.
· Water in basements and crawlspaces is the biggest home owner issue.
90% of it is originates from surface water. Properly functioning perimeter drain
is important. 98% of all basements will get wet at some point. New home warranty
statistics say 38% of homes have water in there basement in the first 5 years.
· Wonder why basements leak? One cubic foot of water weights 62 pounds.
Lets say the water table rises one foot and the footprint of your house is 1000
square feet. 1 ft X 1000 sq.ft X 62 pds = 62,000 pounds or 31 tons of hydrostatic
pressure pushing against the foundation. Maybe the perimeter drain is clogged
or collapsed and is not properly functioning. Besides leaks you may also get
heaving of your foundation or floor slab. If there are any signs of moisture
in the basement or crawlspace the downspouts should be redirected away from
the foundation so they empty at least 6 feet away.
· Central air conditioning and refrigerators operate on exactly the
same principle. Both use a refrigerant called Freon which is non corrosive,
toxic or flammable but is not great for the earths ozone layer. This refrigerant
is a colorless gas at atmospheric temperature and pressure. The refrigerant
Freon has a boiling point of -20° F at atmospheric temperature. This is
the temperature it changes from a liquid to a gas. Its boiling point rises as
the psi (pressure per square inch) is increased by the compressor.
· Always give freezers, refrigerators and air conditioners five minutes
before restarting to allow the pressure on both sides of these low torque compressors
to equal out. Other wise the compressor will be damaged.
· The cooling capacity of air conditioning is measured in tons. One
ton equals 12,000 BTUs per hour. The term 'one ton' comes from the amount of
heat required to melt a block of ice that weighs one ton. Guide lines for calculating
air conditioner size are one ton per 1000 square feet of living space.
· Cool air is more heavy and dense than warm air. Warm air rises, cool
air sinks. Location of heating and air conditioning registers is important for
return and supply air.
· An average size air conditioner (3 tons) can generate two gallons
of condensation per hour on a humid day. The air conditioner evaporator coil
is usually located right above the furnace heat exchanger in the supply air
plenum. The evaporator coil has a condensation pan located right beneath it
to catch all the condensation. If the condensation pan leaks from rusting out
or overflows from a clogged drain on to the heat exchanger, the heat exchanger
will rust out, reducing the furnaces effectiveness. Possibly creating an unsafe
situation with a risk of carbon monoxide entering the house. Furnace replacement
is normal when a heat exchanger becomes defective. Maintenance regularly is
an under statement.
· Air filter maintenance has a huge impact on equipment efficiency.
Poor air flow will cause heat exchangers to overheat. No air filter will clog
up air conditioner coils, heat exchangers, dirt build up on blower fan blades
and dirt in ducts. Poor performance and possible health affects are the issues.
· Rough rule for calculating heat pump sizes is 40 BTUs per square foot.
· An electrical current flow of less than one amp can kill a person.
· Electricity travels at nearly the speed of light, which is 186,000
miles per second. That's a mile in .0000053 of a second.
· A regular 100 watt light bulb has a surface temperature of roughly
380°F . Light bulbs will generally burn cooler and last longer if they burn
with the base down.
· At 10 cents per kilowatt of electricity, if you left a 60 watt bulb
on for 24 hours a day for a week it would cost $1. If you left it on for a year
it would cost $52.
· Smoke detectors, etc. may use batteries. Conventional alkaline batteries
may last one to two years. Lithium type batteries can last up to ten years.
· Loose electrical wire connections cause more fires than any other
· Aluminum wiring is known for overheating problems. It was used from
the 1960's to the mid 1970's. Tends to creep out from under terminal screws.
Receptacles with heat generating appliances plugged into them on a regular basis
are the most troublesome. It is recommended to have aluminum wiring checked
on a regular basis for loose connections that cause overheating.
· The small slot on a female plug is the hot connection and the large
slot is the neutral. Polarity matters with some appliances. Electricity is meant
to flow through the button on the bottom of a light bulb socket. If the polarity
is reversed (neutral and hot terminal reversed), the threaded collar could be
hot, much more likely to get a shock just changing a light bulb. With an appliance
the power should only go as far as the switch. If the polarity is reversed,
power will go through the appliance back to the switch. Many appliances will
work just fine, however, the polarity has to be right to provide the protection
designed into the system.
· Operating high temperature relief valves on hot water heating tanks
is important. For example water can become superheated in a hot water tank by
a burner that won't shut off because of a defective thermostat. Lets heat the
water up to 300° F. Water boils at 212° F, but in a hot water tank it
can't expand so it can boil off into steam. When the tank ruptures, we have
40 gallons of water that would really like to be steam. There is a tremendous
amount of energy released as this amount of water converts to steam. Every cubic
inch of water becomes a cubic foot of steam! The steam explosion is enough to
lift a house off its foundation. Water heaters have gone right through houses
and up well over a 100 feet into the air. These temperature relief valves along
with other isolating valves that do not get used except in emergency or repair
situations should be checked by a plumber, mainly because of their lack of use
they tend to drip after they have been used.
· Water heaters that keep water at 160° F may only have a 60% life
expectancy of a water heating tank kept at 140° F.
· Oil fired water heaters have the fastest recovery rate and so have
the smallest tanks. Gas fired water heaters are the next fastest. Electrical
hot water heaters have the slowest recovery rate and usually have the largest
· Propane is heavier than air. Propane water heating tanks should not
be located in low areas. Leakage of propane gas may cause an explosion.
· Garborators can be tough on septic systems because of the amount of
solids put into the system. If the solids don't separate or decompose, they
will find their way into the tile bed and cause it to fail prematurely.
What is the magic of 34 feet with reference to wells. Atmospheric pressure
is 14.7 psi. One psi can push water up 2.31 feet. 14.7 psi X 2.31 feet = 34
feet. Minus resistance, 25 feet is a practical number. Shallow well is anything
less than 25 feet. Deep well over 25 feet. A pump can pull water up about 25
feet, any deeper than 25 feet requires further evaluation.
· 3/4 inch diameter copper pipe is actually 225% bigger than 1/2 inch
pipe in a cross sectional area. The water flow through the 3/4 inch pipe is
actually 270% greater than flow through 1/2 inch pipe with some pressure loss.
· A home inspection is an educational and informative experience. It
helps understand the nature of the problem if any and general approach for corrective
action. This helps deal with tradespeople from a position of strength and knowledge.
Learn regular home maintenance and gain valuable guidance to preserve the property.
Helps you recognize components that are functioning now but may wear out and
require replacement. Being alert to systems that may be approaching the end
of their life and future expenditures.
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