home + garden

Q We want to disable the heating ducts, called transite heating, that run under the basement's concrete floor. How do we do this?

A The common solution is for a concrete truck to pull up to the house and fill the ducts with concrete.

What you're talking about is the plastic or sheet-metal ducts that deliver heated or cooled air to a finished basement or lower level of a home through grilles in the concrete floor. These are not the radiant heating systems with sealed water pipes or electric coils embedded in the floor.

Very popular in the '80s and '90s, transite heating is less so now. What happens too often is that water seeps into ducts along with organic material from being underground. The moist, dark conditions in the duct are perfect for mold and bacteria. When the furnace or air conditioner pushes air through these ducts it picks up contaminants and spreads them throughout the house. Mold can contribute to allergy or asthma problems and sometimes is toxic. With standing water, there is concern of disease such as Pontiac fever and Legionnaires'.

Once these ducts start to leak, it usually means that they have to be disconnected or abandoned. Replacement ducts are then installed in the walls and ceilings.

Contact several heating specialists for bids and suggestions to find the one with expertise to do the job. They can subcontract the concrete work for you.

If your home has transite heating, periodically remove the grilles and check to see that ducts are clean and dry.

Don't buy a home with transite heat ducts without checking them carefully and getting proof that they haven't leaked. Some experts recommend against buying a house with these ducts because they can be so problematic in addition to being an entry point for radon.

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-9033, or e-mail fixit@startribune.com.