Architect writes:

"We are called upon to remedy a trouble that seems to be very general, and we would like to have your advice through your paper as to the best means of remedying it. The hot and cold water pipes in the house in question are fastened to the ceiling of the basement: the hot-water pipe is painted, the cold-water pipe is not. They are both lead pipes. Since the furnace has been stopped the cold-water pipe sweats to such an extent that the floor in the basement is wet all the time. Can you suggest any remedy that would overcome the trouble in a simple and inexpensive manner?"

[Your trouble is simply the condensation of the moisture in the air on a cold surface, the same thing that occurs on the inside of the kitchen windows in winter and on the outside of the ice pitcher in summer. The remedy is to surround the pipe with some non-conductor so that the exposed surface shall not be so cold; any non-conductor will do, but if pervious to the air like felt it will be kept damp by the moisture passing through it and condensing on the pipe inside, and will be liable to rot. A thick coat of paint will somewhat reduce the condensation and will be the neatest arrangement. If the paint is thickened with ground cork the condensation may be reduced to an inconsiderable amount, although the job will not be as smooth. Such paint is used on the interior of iron ships for a similar purpose. If ground cork is not readily obtainable probably sawdust would answer a similar purpose, though it is not quite as good a non-conductor. The increase of your trouble since the furnace fire went out has probably nothing to do with the absence of the furnace fire, but is most likely due entirely to the fact that there is much more moisture in the air in summer than in winter, and hence more of it is condensed on your cold pipe.]