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Control moisture to control mildew
Sep 17, 2004

Mildew, a black fungus that sometimes appears as a white, red, or green powder, grows on most surfaces and spreads rampantly in dark unventilated places. Although it’s unlikely to cause major damage to the structure of the house, mildew is unsightly and emits an unpleasant musty odour. Its spores can also cause allergic reactions in susceptible people. 

Mildew is prevalent in humid summer weather, exactly the kind of weather that we have been experiencing this summer. You’re likely to discover it wherever air cannot move easily: in basements, bathrooms, crowded closets, and closed cabinets. Because building materials hold a lot of moisture, mildew can thrive during the first year after a new home is built. 

You can start attacking this fungus by decreasing dampness and increasing air circulation. In closets, replace wooden shelving with wire racks and install louvred doors. Empty and air out the closet and then clean it with a detergent and water solution (whenever using detergent, check the manufacturer’s instructions on the product label).

Or, you can dry the air inside the closet by burning a 60-watt light bulb for 24 to 48 hours (mildew prefers dark, dank places). If mildew reappears, leave the bulb on constantly. To prevent fire, keep the bulb at least 18 inches away from stored items. 

In the basement, correct any moisture problems, and if necessary, run a dehumidifier. Cover the floor with vinyl flooring instead of carpeting because vinyl acts as a vapour/moisture barrier. Vinyl will also prevent alkali salts from working itself up through the concrete floor. In bathrooms and the laundry area, install exhaust fans and repair any plumbing leaks.  

To keep mildew from growing on exterior siding, trim back shrubbery to let air circulate and let the sun dry the siding. (This may also clear up interior mildew caused by dampness inside the exterior walls.) Prevent condensation in attics by installing a combination of soffits and continuous ridge venting. Make sure that the ridge venting is screened to prevent insects from getting into your attic. 

When you have mildew on painted surfaces, before repainting, clean mildew off the surface using a detergent and water solution. 

If you think that just cleaning the surface and repainting it will get rid of the mildew, you’re wrong, as mildew will actually eat through the new paint. In your paint and primer, mix a mildewcide additive, available at paint supply stores. Or select paint with zinc oxide pigment. Oil paint resists fungal attack better than latex; among latex paints, acrylic is the most resistant. Coating unfinished wood with a water-repellent preservative containing a fungicide will deter mildew. Or, if you have mildew on an unpainted surface, remove it by using a detergent and water mixture. 

For wallpaper, there is no cure. Fungus feeds on wallpaper glue. Re-wallpaper after cleaning the wall by mixing borax into a paste or paint the wall with a paint containing mildewcide. 

To remove mildew from clothing and household fabrics, use soap or detergent and water. For remaining stains, add lemon juice and salt to one-quart warm water.

For wood, plastic laminate, metal or plaster surfaces, make a vinegar and borax solution because water raises grain in wood. 

Caution: Whenever using the regular home cleaning products or commercial products always wear rubber gloves and make sure there is plenty of ventilation. When using commercial products, follow the directions on the label.