Moisture Invasion from "within."
The most obvious problem you may encounter is from leaky plumbing pipes and mechanical equipment. Even new plumbing can leak, but older water and sewer pipes are particularly vulnerable.

As a result, slow leaks at plumbing joints hidden within walls and ceilings can stain ceiling plaster or wallpaper, ultimately rot floor boards, and even lead to decay of structural members! Maintaining and repairing, or, if necessary, replacing older plumbing and mechanical equipment are the most common solutions.

Next, condensation produced inside the house can create some real headaches! It's caused when moist warm vapor in the air cools on interior surfaces and changes into liquid. Usually settling on paint, the moist film can result in an unhealthy interior, heavy with mold and mildew spores.

What makes it worse is that the condensation invader is primarily occupant produced! Did you know that a house with four people in it can generate between 10 and 16 pounds of water a day (approximately 1 ½- 2 gallons) from normal, every day activities, such as showering, cooking, and doing laundry? Unvented gas stoves and kerosene heaters also give off a large amount of unwanted moisture. Bathrooms, kitchens, and laundry areas should all have vent fans that are turned on when the rooms are in active use.

When moisture appears as a film on interior window surfaces, it's a sign that you need to take defensive action. In cold climates, install storm windows. This reduces condensation and its damaging effects to historic materials, as well as your health.

In summary, reducing condensation through additional ventilation or installing storm windows can really help preserve your historic house!

  What to do--or not do.
The best advice is to use common sense maintenance procedures to reduce damage from interior moisture. Here are suggestions to keep the invaders under control with a focus on keeping equipment functioning; replacing broken components; and even installing additional equipment where moisture problems are evident.

Plumbing pipes: Consider use of a floor water sensor in the basement to let you know if you have a problem! Add insulation to plumbing or radiator pipes located in areas subject to condensation or freezing, such as along outside walls, in attics, or in unheated basements.
Replace older pipes that are subject to leaking or overflowing!