A ghastly dilemma for your carpeting

You may define it as ghostly instead of ghastly.  It’s carpet ghosts. Your  light-colored carpeting has taken on a dark line at the perimeter of every room and even at the base of every door.

You've tried vacuuming it and washing it, but it won't go away. Your next step is to contact the carpet company and start complaining big time. What could be causing these "ghosts" in your new, expensive carpeting?

Discoloration is caused by one or a combination of culprits, but probably has nothing to do with the quality of the carpet itself. An accumulation of small particles in the interior air of your home may be at work, and only a professional carpet cleaning with enzyme-based agents may help.

Just as we look for the root of health problems to find a cure, researchers have studied out why this ghosting phenomenon occurs even in newly-built homes. The source of these particles is generally identified as substances such as tobacco smoke, wood-burning smoke, drywall dust, house dust, and home projects such as sanding, grinding and finishing. Also included in the list of possibilities are airborne pollution particles, organic material, automotive exhaust, and road dust.

Air movement not only within the house but also throughout the home's wall structure may be contributing to the phenomenon. Air movement and temperature gradients are present in every home. These mechanisms cause attraction of airborne particles to exterior walls or leakage points in the home. When particles are drawn to a leakage 'path,' for example, at the base of a wall, the carpet can act as a filter that retains the particles. Over time the particles build up and become visible.

The most recent and increasingly common form of staining is caused not by dirt or dust but by soot. Ghosting from soot is seen primarily in more recent construction, but diagnosticians have detected soot stains in older residences as well.

Experts tell us that three known forces can be responsible for the deposits: impaction (forced air), gravity, and attraction (electrostatic forces and moisture) and the location of the deposits gives a good indication of which of the three forces may be responsible.

According to the National Association of Homebuilders (NAHB), some discoloration in both carpeting and walls is likely to occur in all homes, but steps can be taken by homeowners to address it. Among them are reducing tobacco smoke, candle-burning, and fuel-burning appliances. Automotive refinishing, woodworking and dust-producing activities may be the cause,  so perform them well away from your home's doorways and open windows.

Try not to let cars idle in attached garages, always use an exhaust fan when cooking and clean your carpeting regularly, using a crevice tool around your baseboards. And don't forget to replace your central heat/air vents on a regular basis.

If you're having a home built, you may want to head-off future carpet problems by taking these steps.

1. A tight duct system will help to minimize air leaks.

2. Make sure the filter on the furnace is changed before you occupy.

3. If the home is being built, ask your builder not to use the HVAC system during construction activities.

4. Use qualified contractors to install proper vents on appliances, wood stoves and fireplaces.

5. Make sure the draft on the fireplace flue is adequate.

6. Minimize air leakage from the garage to the house by sealing door openings tightly with weather-stripping.

7.  Actively looks for leakage routes at door thresholds,