Two days later, again I heard the tapping — five clear, rapid beats, then a pause, then five more beats. Pause. Five beats, followed by a metallic echo.
To my ear, the beats seemed to emanate from a pipe somewhere. I was pretty much convinced of that.
I Googled “drumming sound in pipes,” and something called “water hammer” topped the search results.
Water hammer is “a phenomenon that can occur in any piping system where valves are used to control the flow of liquids. It is the result of a pressure surge, or high-pressure shock wave … and may be characterized by a marked banging or knocking sound on pipes.”
Another source said a “surge of pressure can cause pipes to jerk and thud against wall framing or other pipes.”
“I notice you don’t have an expansion tank over your water heater,” the plumber said, referring to a tank designed to absorb excess pressure in the household plumbing. Also, he said, such a tank would be required before the next sale of the house.
I had no doubt that every word of that was true. But would it eliminate the mysterious sound in the pipes?
The plumber could not say. He was only sure of one thing — the house needed another expansion tank, and if not this day then another.
Now I had to weigh a proposition: The plumbing company was already going to charge me a diagnostic fee. If I wanted, he could get the new tank delivered and have the thing installed in an hour without having to come back another time for another charge.
It made sense. And perhaps the new tank would calm my grumbling pipe.
So I had the plumber install the expansion tank, and he secured some loose pipes with new supports. The total charge came to $344.
After two hours of lovely quiet, the hammering started again: Five rapid taps, a pause, followed by five rapid taps. Pause. Taps. Pause. Taps.
I went into the basement again. The hammering seemed to be coming from above the furnace. I was bothered and bewildered.
The plumber had asked me to call if the hammering continued, but I let it go, hoping it would go away.
Come the next morning, when I stepped out the front door, I was startled by something like a rivet gun. It seemed to come from my neighbor’s house across the street, or somewhere above it — a loud metallic burst that left a ringing echo.
Had my name been Nigel and had life been a British sitcom, I might have uttered, “What in bloody hell?” or, “Good god, what was that?”
Moments later, it started again, but this time closer. It was above me, above my house — the same rivet gun racket!
My eye went to the roof and then to the chimney and then to the metal cap on the chimney.
A woodpecker fired off another round: Ratatat-tat-tat!
A woodpecker had been hammering on my chimney cap? A woodpecker had been hammering on my chimney cap, sending heavy metal sound waves through my house?
Some grouchy old pipe hadn’t been making the noise?
A woodpecker had prompted me to call the plumber, prompting the plumber to sell me an expansion tank I didn’t know I needed?
A woodpecker had been using my chimney cap to make noise, establish territory and attract a mate?
I found that on Google, under, “Woodpeckers pecking on chimney cap.”