12" Turbine Ventilator Installation Instructions
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To determine the number of turbine ventilators needed to properly ventilate your attic, first determine the size of your attic in square feet. Simply measure the length and width of your house, and multiply the two figures for the total square foot area. One ventilator is required for each 600 square feet of attic floor area. Note also that for satisfactory operation of these ventilators, a minimum of two square feet of louver area is required for each ventilator, around the eaves and/or exterior of the house to let outside air into the attic.


For optimum performance, the turbine ventilator should be installed near the peak of the roof on a rear slope with the rotating head above the peak, exposed to the wind from all directions. When installing two, place each 1/4 the distance from the end of the house. When installing three, place one in the center and the other two 1/6 the distance from each end of the house. Position of the ventilators should be free of rafters to ease installation, although this is not essential.


  1. Locate adjustable base in the position(s) selected as per above instructions.
  2. Trace a circle on the roofing surface using the inside diameter of the adjustable base as a guide.
  3. Use a sharp cutting tool to remove roof shingles or material from inside circle. Remove any fasteners or shingle nails adjacent to the outside of the circle that will prevent the flange of the base from seating properly.
  4. Saw out the roof boards within the scribed circle.
  5. Loosen hardware on the adjustable base. The base is adjustable at the middle seam. Rotate the base at this point to make the top portion level when the base is seated over the roof opening. Tighten screw.
  6. Butter roofing cement in area around roof opening. Set the base in the roofing cement so that the top portion of the flange slides under the shingles. leaving the bottom portion of the flange over the shingles. Securely fasten the base to the roof with a minimum of eight large head roofing nails.
  7. Caulk all nail heads. Apply roofing cement to the shingles which extend over the flange, to the edges of any shingles which have been cut, to the high side of the base's seam where it meets the vertical airshaft and to the exposed edge of the base mounting flange which is over the shingles.
  8. Fasten ventilator airshaft in a level position to the crimped collar of the base airshaft with a minimum of six sheet metal screws. Be sure the ventilator is level for proper operation.