Ventubes are hollow cylinders constructed of 100%, 304 series stainless steel. Each tube is 1/2″ in diameter and 4 1/2″ in length. A wire screen is welded in the front of each tube to prevent insect intrusion. VenTubes provide cross ventilation in chimneys with large cavity areas surrounding the flue liner. The tubes help prevent water damage caused by condensation common to this type of chimney construction.
Ventubes prevent moisture damage that results from condensation in the large cavities, or chase areas, surrounding flue liners. Moisture vapor held in large cavity areas often condenses on the inside of outer chimney walls when wall surface temperatures fall below air temperatures.
VenTubes help to prevent the efflorescence, spalling, and freeze/thaw damage that is caused by condensation in these cavity areas. VenTubes can eliminate up to 85% of the moisture that damages chimneys with large chase areas. Easy to install, they solve an often overlooked moisture problem.
Years of field observation indicated that chimneys with large cavities surrounding the liners deteriorate much faster than chimneys built according to the recommendations of the Brick Institute of America (BIA), which recommends one inch of air space between the liner and outer brick.
Note: Do not install VenTubes in chimneys which have damaged, cracked, or misaligned flue liners. Do not install Ventubes below the roof line or other combustible exposures.