However, you may not realize that there could be an unwelcome "creature" inside your home that also should not be fed: mold.

Like the animals at the zoo, mold needs a food source to grow. The growth of mold in homes can present health-related problems and require expensive home repairs.

Mold can grow where there is a food source and high levels of moisture. Food sources for mold include wood, paper and organic fibers in fabrics. Some homeowners have to completely remove and replace walls and ceilings where the mold growth has been discovered.

The good news is that you can reduce the food supply of mold. The National Concrete Masonry Association offers the following tips to avoid mold growth:

* Look for visible signs of moisture and eliminate the source.

* Maintain roofs, walls and openings. Replace caulking and repaint as needed.

* Inspect and clean the condensation drain line for central air conditioning units.

* Inspect the roof, windows and siding after storms to identify missing shingles, damaged flashing and visible water leaks.

* Seal all outlets, sill plates and through-wall penetrations including doors and windows to minimize uncontrolled air infiltration.

* Keep the maximum relative humidity levels in your home at about 40 percent during the heating season and below 60 percent during the cooling season as recommended by the National Association of Home Builders.

* Install bath and kitchen fans. Vent fans and clothes dryers to the outside of the building.

Lighter-weight materials used in many new homes provide more food sources for mold to grow. Alternatively, walls built with concrete masonry do not provide a food source for mold.

When infected by mold, wall systems made of wood or paper will most likely require complete removal while concrete masonry can be cleaned.

For more information about cleaning concrete masonry, visit www.ncma.org/cleaning.