I read an article about winterizing your home and there was a comment that chalky substance on brick can indicate a serious problem, yet they never state the problem. I own a 1940's Georgian and the only area where we can see the brick is in the basement where the water heater and furnace are located. There is a white chalky substance on the brick and floor. What is it, is it dangerous, and who do I contact?

chalky residue on brick