tapping/knocking sound only in warm weather?
All last summer and now this year, too, I have had a problem with an intermittent tapping/knocking sound in my house. The sound only occurs in warmer weather, but it occurs day and night. Last year I thought that it might be animal-related (like a woodpecker of some sort), but the animal/bug control company I called last year saw no signs of damage and said that the day/night pattern ruled out birds. I now think it must be plumbing-related because I can feel a couple of the water pipes in the basement vibrating when the sound is happening.
Can anyone suggest what I ask my plumber to look for when dealing with it? The sound is intermittent so I can't count on it happening when he's here. Plus my usual plumber is somewhat hard of hearing. I'd like him to do the work if possible, but I'm not sure he can hear the problem.