Roof Ridge Rot

This was a 10 year-old, heavy-duty asphalt shingle roof in Danville with a 40-year warranty.

Provided it’s safe, home inspectors climb onto roofs to look at the conditions.

The roof field looked great, but every single roof ridge shingle was deteriorated. Why?

Before roof manufacturers manufactured roof ridge shingles, roofers would take a standard organic asphalt shingle – remove the tabs – fold the shingle back on itself and use it as a ridge shingle.

These organic shingles would last 6-10 years due to the sun’s UV rays drying out the shingles and making them brittle.

Using a newer fiberglass shingle in this manner proved to last much longer.

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Retaining Wall Woes

A section of this Castro Valley property retaining wall was leaning.

The three most common signs of imminent retaining wall failure are leaning, cracking and bulging.

The main cause of retaining wall failure is poor drainage at base of the retaining wall and no weep holes

A secondary cause of failure is not having a deep retaining wall footing (the concrete base in the ground that the wall sits on)

Engineering talk – When water accumulates behind a retaining wall, it pushes on the wall with a lot of force hydrostatic (water) pressure – thus the leaning section of retaining wall in the photo.

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Spitting Water

The House Whisperer checks dishwasher drain cycles and routinely finds 15% of dishwasher drain hoses are blocked with food sludge or are kinked.

This causes water to spray out of the air gap device. What’s an air gap device?

It’s a small cylindrical fixture with slots, that’s installed between the dishwasher and the kitchen sink drain pipe or garbage disposal.

It sits on the sink deck or the kitchen countertop and is designed to prevent dishwasher drain water from flowing backwards into the dishwasher – a good thing since food particle bacteria is present in the drain hose.

If water flows out an air gap device, it’s a red flag.

Usually, there’s food blockage at the garage disposer connection, the drain line is kinked, or the knockout plug in the garbage disposal wasn’t removed during installation.

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Rodent Hotel

With cold weather comes rats, raccoons, possums, mice, squirrels, birds and bats seek shelter and can find their way into attics and crawlspaces.

During a Blackhawk inspection, the home inspector discovered that wall insulation had been pulled down and shredded by visiting rodents.

Insulation makes great nesting material, which usually becomes contaminated with rodent droppings and urine – a health safety concern.

Rodents will chew through wood, plastic, PVC pipes, roof underlayment, rubber, electrical wiring, fiberglass insulation, and paper with great ease.

The threat to electrical wires is a serious fire-hazard. Many unexplained house fires are attributed to rodents in the attic or crawlspace.

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This is a water heater temperature, pressure safety valve.

When something goes wrong within the water heater, the safety valve is designed to open and release high temperature water and excessive pressure through a discharge pipe to the exterior of the house.

Here, there is no discharge pipe and the safety valve was plugged, probably by a home owner who saw water dripping from the valve.

This is a recipe for disaster.

If the gas flame that heats the water in a gas-fired water heater fails to turn off at a set water temperature – the water temperature and tank pressure will increase – and at some point there will be an explosion of the tank.

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Water Heater Lava

During a recent Pleasant Hill home inspection, the inspector discovered what you’d expect to see coming out of a volcano – lava.

This is the top of a water heater tank that’s heavily corroded and what happens when copper pipe is connected incorrectly to steel pipe.

Technical talk: this is called galvanic corrosion and refers to corrosion that occurs when two different metals are in electrical contact with an electrolyte.

Inspector talk: copper and steel are dissimilar metals and if not insulated from each other, corrosion can take place.

With a corroded pipe and water seepage – the photo made for a lava flow of sorts on top of the water heater.

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Charred Crawlspace

The home inspector was crawling under a San Jose home and while shining his flashlight, illuminated blackened subflooring and floor joists – he couldn’t believe his eyes.

Nearly all of the subflooring and crawlspace support structure was completely charred – think charcoal used for BBQs.

The home owner had no idea about the charred crawlspace and how lucky they were that the house didn’t burn down.

It was determined by investigators that electrical wiring in the crawlspace had been gnawed by rodents causing a fire to start.

Because of the large wood surface areas (flat subfloor, floor joists, cripple wall studs), the fire smoldered (burnt, but no flames) and crept along without full combustion – essentially producing charcoal.

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AC Unit Attacked

During a Los Gatos home inspection, the inspector spotted a gaping hole in the outside air conditioning (AC) unit.

Upon closer inspection, the inspector knew that there had been several pit stops by a male dog.

Scent marking is a natural behavior that dogs use to mark territory and communicate with other dogs.

It turns out that dog urine acts as a strong alkali (corrosive substance) on the AC aluminum cooling fins and literally dissolves the metal.

The performance of the air conditioning system was compromised and cost a few thousand dollars to replace the unit.

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Missing AC Unit

During the Great Recession of 2008, the home inspector rounded the back of a vacant home spotting the remains of where an air conditioner unit once sat.

The air conditioning unit had been stolen, as parts of the AC unit were made of aluminum and copper.

Copper theft reached all-time highs in 2007-2008 when the price of recyclable copper reached $3 to $4 a pound.

The thefts were happening all over the country, especially where thieves were targeting foreclosed houses.

In 2008, Congress passed The Copper Theft Prevention Act aimed at cutting down on copper theft.

It required certain metal recyclers to keep records of their transactions in order to deter individuals and enterprises engaged in theft and interstate fencing of stolen copper, and for other purposes.

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Aluminum Wire

During a recent home inspection in Moraga, the home inspector discovered aluminum wiring in an older garage electrical subpanel.

Aluminum electrical wiring was installed in houses from the late 1960s to the mid-1970s during a period of high copper prices.

Since that time, aluminum wiring has been associated with a number of house fires.

The main problem with aluminum wiring is a phenomenon known as ‘cold creep’.

When aluminum wiring warms up, it expands and when it cools down, it contracts.

Unlike copper, when aluminum goes through a number of warm/cool cycles it loses a bit of tightness at the wall outlet termination…creating an over-heated condition… and in some cases, an electrical fire.
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