How to prevent mildew on walls

Updated April 17, 2017

Mildew is a black and unsightly mould that grows in unventilated areas, causes an offensive odour and ruins surfaces. Mildew feeds on the wood in living area walls, breaking down the cellulose that mildew needs to grow and thrive. In bathrooms, mildew grows from the moisture left on tile walls. Left to grow and spread unchecked, mildew causes damage to walls. Preventing mildew from growing on walls requires regular cleaning and taking a few precautions.

Eliminate dampness by providing good ventilation in all the rooms. Mildew loves damp and moist environments, so open windows when the weather is nice. Use a heat source to dry a wall surface that is damp. During humid summer months, use an air conditioner or dehumidifier in rooms prone to dampness. Circulate dry air with a rotating fan.

Wipe down walls with a gentle cleaner containing fungicide. Read the label carefully to ensure the cleaner is appropriate for paint or plaster. Mildew feeds on grease, so in cooking areas take care to keep painted wall surfaces free of cooking grease. For tile walls, use a diluted mixture of chlorine bleach or sodium hyperchlorite. Mix a solution of 118 to 236 ml (1/2 to 1 cup) of cleaner to 3.8 litres (1 gallon) of water and wipe thoroughly.

Paint wood and plaster walls with a paint containing mildewcide, an ingredient added by manufacturers to stop mildew from forming. Paints that are oil-based and classified as a light-coloured paint, such as cream, attract mildew more easily; paint wood and plaster walls with paints that are water-based and hard-coloured. On unpainted wood walls, apply a wood sealant to a clean dry surface.

Let the sun in. Mildew runs from the light, so throw open the curtains or, weather permitting, a window. For walls in confined places such as closets, place silica gel on the floor to absorb moisture.

Things You'll Need

  • Bucket
  • Cleaning rags
  • Water-based paint
  • Fungicide cleaner
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About the Author

Chris Larrew is based out of Sunnyvale, Calif., and has edited and written Web articles and content since 2006. For the Yahoo! topic directory "Spark" he has written biographies on Oscar Wilde and Spike Jones as well as articles on history. He holds a degree in English from the University of California, Santa Barbara.