Q. I was told by a plumber and a contractor that I have a rotten sill in my cellar that must be replaced as soon as possible. My Cape Cod house was built in 1950. I haven’t a clue as to what this is and why it happened. I need your help. - MARIE

A. The plumber and the contractor were no help to you because they failed to tell you what exactly happened and failed to offer help, except to frighten you. The sill is the wood beam that sits on the top of the concrete foundation, and the rest of the house sits on that beam, called a sill plate. Parts of it rotted because the basement was closed up tight for 63 years, and water vapor came up through the concrete floor and condensed on the cool wood. Eventually, and especially on the Cape, this water caused the decay.