By Barry Stone
Dear Barry,
The dryer exhaust in my son's home is vented by way of a metal duct below the concrete slab floor. This appears to be an impractical and potentially dangerous installation. Your suggestions for possible improvements would be appreciated. - Reed
Dear Reed,
Underground installation of a dryer vent is unwise because the duct is subject to rust damage from continuous contact with ground moisture. Additionally, coldness of the soil can cause moisture condensation and the accumulation of lint with the duct, and congestion with lint could cause the dryer to overheat.
If a more conventional above-ground pathway to the exterior of the home can be found, that would provide a preferable means of venting the dryer. If not, it would be wise to have the existing duct professionally inspected to determine whether any adverse symptoms have actually occurred. Some plumbing contractors perform video inspections of drain piping. They could probably do the same with a dryer vent duct. That would enable you to determine whether there is an actual problem or merely a theoretical one. If the duct is found to be intact, you might simply need to have it cleaned. If it turns out to be damaged, then the plumber might be able to determine a practical solution, given the layout of the building.
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