Dear Barry,

I bought my house over three years ago, and have had seasonal problems with wet ceilings ever since. After replacing the roof and gutter system, I learned that the problem was condensation caused by ground water seepage into the heating ducts below the slab floor. Shouldn’t my home inspector have known this would be a problem, and shouldn’t the seller have disclosed the issue of ceiling moisture? — Mark

Dear Mark,

In homes built during the 1950s and 60s, forced-air heating ducts were sometimes installed beneath concrete slab floors. This practice, however, was abandoned when moisture-related problems became apparent. Experienced home inspectors are aware of such concerns and know that forced air ducts under a slab are exposed to ground moisture, water intrusion, and resultant damage. Although home inspectors cannot fully determine the conditions that exist within a duct system, disclosure of common problems involving a buried duct system should be expected.

The consequences of buried ducts are not limited to the kinds of moisture conditions you’ve experienced. Other adverse effects include rust damage to the ducts themselves and mold infection on the interior duct surfaces. Mold in an air duct system poses an obvious threat to the health of occupants, because the heating system becomes an active conveyance for airborne mold spores. Replacement of your air duct system is recommended, and a mold survey of your home is advised.

Dear Barry,

Why does the water in our upstairs toilet bowl slosh back-and-forth, even when the toilet has not been used? Our home is only three years old, and the toilet has been doing this since the place was new. Is something wrong with our plumbing? — Alex

Dear Alex,

A change in the plumbing code, effective in some areas, allows several drains to be vented through a single vent pipe. If someone runs water at one fixture, this can create a vacuum in the system that can cause water movement in some toilets. In some cases, it can also create draining problems at sinks. Correction would necessitate a considerable amount of costly and intrusive work, but since the effects are typically minor in nature, repairs of this kind are usually unjustified.

Dear Barry,

I have some questions regarding the temperature pressure relief (TPR) valve on my water heater. How can I tell if it has been activated? Does it reset by itself? Can I reset it manually? And should it be tested? — Buzz

Dear Buzz,

TPR valves are installed on water heaters to prevent the tanks from exploding if the fixture should overheat. The valve is held in the closed position by means of a spring. When the pressure or temperature in the tank causes the valve to open, hot water is released from the system. If the valve is working properly, it will reseal by itself when the temperature or pressure returns to normal. Most TPR valves, however, never fully reseal because of corrosion or mineral deposits. That is when the valve needs to be replaced. Testing of TPR valves is not recommended because they often tend to leak after having been tested.

To write to Barry Stone, please visit him on the Web at


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