Window Door and Wall Collage

    These Methods Protect Doors, Walls, and Windows from Moisture Damage

    Have you been in a home with warped doors, peeled or blistered paint on walls or window frames? Maybe this sounds like parts of your own home? The reason is simple; excess moisture and condensation. With regards to doors and windows, maintaining too high relative humidity eventually diminishes the functionality and aesthetics of doors and windows. It also creates a breeding ground for mold.

    How to identify the source of moisture

    Recognizing that there is too much humidity in your home is the first step. Since our comfort levels are different, people may not generally know when it is above 60% RH (relative humidity) in their home. A hygrometer is an inexpensive and accurate tool that can display the current humidity in the room it is situated in. Most hygrometers today are digital, compact, and include a thermometer as well.

    Excess moisture can come from several sources, both in and out of the home, but most humidity issues occur naturally due to outside conditions, warm air can contain much more humidity than cold.

    In the warmer months, especially near big bodies of water, the air outdoors carries a lot of moisture that can enter your home in several different ways including, open windows and doors, and through ventilation.  This is the biggest reason for humidity problems in every home, especially in basements and crawl spaces.

    Common indoor activities such as bathing, cooking, dishwashing and simply breathing also produce moisture. Other moisture sources in the home include:

    • Plants
    • Humidifiers
    • Stored firewood
    • Plumbing leaks
    • Damp soil under many basements and crawlspaces
    • Poor ventilation in the home

    Wooden door

    Why do doors warp?

    Most doors are made of organic material; especially wood. Wood is susceptible to water and moisture because of its ability to absorb moisture. When a door absorbs enough moisture and dries unevenly, warping or deformities in its shape can occur, resulting in a door that sticks, or catches on the jamb every time you attempt to open it. Signs of damage can also appear as:

    • Stripped screws
    • Door looks swollen
    • Bow in the door

    Most types of doors have the possibility to warp, but some are more susceptible and sensitive to indoor climate conditions. In general, it is more common for a bow to be introduced in older doors and/or taller doors. This includes interior and exterior doors, as well as solid, hollow, and raised panel constructions. Other variables include the type of wood and sealant/finish used.

    Areas of the world with extreme seasonal changes from humid summers to very dry winters have a higher probability of dealing with doors warping.

    Having doors made of steel or inorganic materials such as fiberglass, that does not shrink or expand is an option but does not protect the rest of the home from damage caused by excess moisture.

    In these instances, controlling your indoor climate is essential to avoid costly and aggravating events such as fixing or replacing a warped door. A dehumidifier is the most beneficial solution in maintaining adequate relative humidity in your home and keep your doors from bowing or warping.

    Detail of mold, dirt and water drops on the window

    Avoiding damage from window condensation

    What to look out for: Sweating/foggy windows, wet window frames, paint chipping or peeling around window frames, rot, and areas of mould.

    Reasons: Warmer air indoors than outdoors. When air cools to its dew point through contact with a surface that is colder than the air, (in this instance, a window), water will condense on the surface, essentially turning airborne water vapor into liquid water (dew). This is mostly attributed by any or all of the following:

    • Homes being sealed tight in the colder months with poor ventilation.
    • Too many occupants breathing out humid air.
    • Lack of air circulation caused by objects blocking windows and vents.

    Many newer homes and apartments have the issue of being too “airtight” with the way they are constructed, including the addition of double or triple-pane windows. Homes that have poor air circulation humidity created indoors build up on windows, through condensation. Left alone long enough, and damage can occur.

    Preventative Actions

    If your home or apartment is “sealed like a vault” to avoid having heat escape in the winter, then we suggest cracking windows open in short increments several times a day to increase ventilation without noticeably dropping the indoor temperature. Here are other useful tips for minimizing the chance of condensation building on your windows.

    • Keep areas around windows uncluttered and don’t block vents with plants, curtains, roller blinds, decorations, etc.
    • Ceiling fans and air purifiers can help recirculate the air indoors.
    • We also recommend using a dehumidifier in areas of condensation, but we recommend the relative humidity indoors stays between 40-60%, as too low humidity has its own set of negative effects. Additionally, a laundry dehumidifier is a suitable investment for homeowners who air dry their laundry.

    These preventative steps will significantly help you avoid mould, as well as flaking or peeling paint on wooden window frames, and possibly rot.

    Protecting walls from excess moisture

    Whether you are renovating, freshening up a room, or working as a recovery effort from water damage, walls (drywall/sheetrock/concrete) need to be fully dry before painting begins.

    “Paint that’s applied to a damp surface or paint that’s exposed to high humidity can peel easily”

    Moisture and humidity affect the paint’s adhesion and cause it to eventually begin flaking off. If your painted walls are starting to peel, crack, or blister, you most likely have an issue with too much ambient moisture in that area of the home.

    How to fix a painted wall damaged by excess moisture:

    • Make sure the area is dry and that the moisture level in the room is below 60%. This can be achieved by running a dehumidifier in that room.
    • Scrape away the damaged areas of paint using a paint scraper and a wire brush.
    • Repair any holes or cracks in the wall with spackling paste or a patching compound.
    • Verify that the paint is able to fully dry in an arid environment.
    • Maintain adequate humidity levels in your home by monitoring with a hygrometer.


    Here is a recap of the methods described, in controlling your indoor climate while protecting your home’s assets.

    • Identify the source of moisture.
    • Invest in a hygrometer.
    • Circulate your air: Do not block windows or vents. Ceiling fans and air purifiers significantly help recirculate indoor air.
    • Dehumidify essential areas in the home where the relative humidity (RH) is above 60%.
    • Better to keep windows closed on hotter, humid days and use a dehumidifier in a basement or near wet sources (laundry/bathroom), and an air conditioner in other parts of the living area.
    • If you are going to air dry your clothes, consider a laundry dehumidifier, that blow-dries hanging laundry quickly and efficiently while dehumidifying the surrounding area.

    Do you know someone whose home either has a musty scent, paint peeling on walls and surfaces, windows covered in condensation, or issues with their doors? Share this article with them! For more information on indoor air mitigation, visit