What to do when moisture gets inside your home

Where do you begin?

Moisture can come from several sources. However, the most frequent sources of moisture inside the home are the plumbing, roofing, basement seepage and condensation. No matter where the source is it must be found and eliminated.

Moisture damage in some cases may take some time to become obvious. It is easy to see a wet spot or stain on the wall, ceilings, under cabinets or basement floors. In other cases, the moisture evidence or damage may not show itself for some time, thereby allowing for the growth of mold, rot or deterioration of some of the house’s components.


Plumbing leaks occur at baths, kitchens or any place in the house where water conduits exist. Joints become loose. Fixtures can leak. Pipes deteriorate with age. When you have galvanized iron water piping or cast iron waste pipes, once the rust and corrosion have deteriorated a pipe to a point holes exist, a leak can occur. Waste stacks are many times in walls hidden from view. In some of the older houses, there is an old lead horizontal pipe that ran from the tub to the stack that will be completely hidden until you see signs of leakage or remodeling is in progress.


Roofing leakage in addition to defective roof covering can be caused by poor, missing or damaged flashings. Flashings are covers for transition joints (pipe protrusions, chimneys, walls, etc.). The flashing when installed correctly is designed to get the water to run around the protrusion. Storms (wind, hail, ice, snow, etc.) can damage shingles and even slate roofing. In some cases if over a bath they may appear as plumbing leakage making locating the source a little more difficult. Ice damming can create leakage along the outer edge of the roof allowing moisture into the walls and ceilings below.


Condensation can occur on the interior components of the home when the humidity in the house is higher than desirable and/or components such as metal windows or cold basement walls are cold and the high humidity condenses on these components. When we cook, bathe and clean we create moisture inside the home. Humidifiers on the furnace are intended to provide a more comfortable living environment by adding moisture to the living environment. When set to high they can also create to much interior moisture.

Many areas throughout the country, like where I am, St. Louis, MO , have considerable humidity in the summer. Homeowners located in these areas, that have basements, should have dehumidifiers. These will help take some of the moisture out of the basement during April through October of each year.

So what do we do?

Always locate the source of the moisture. Correct the cause before correcting the damage. It may be something as simple as repairing a pipe joint. In some other cases as noted this can be difficult. It may require some investigation, destructive in some cases (i.e. opening walls and ceilings, etc.) to determine the source of the leak. Professionals can some time help locate these sources.

About the author:

Gerry is a licensed Professional Engineer in four states; Missouri, Illinois, Colorado and Kansas. He first began his home inspection career in 1976 and has been active in ASHI (American Society of Home Inspectors) since 1978. In fact, Gerry’s membership number in ASHI is 87 compared with most of the memberships numbers which are in the 1,000’s. Gerry has performed over 16,000 inspections. Gerry can be reached by email at gloesch@bpgwi.com or by phone 314-249-8370.

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