How To Do Duct Work in Basement Walls

Measure the inside of the basement walls to determine what size air ducts you can use.

Assemble the duct work sections without taping them and hold them up in the installation location. Trace around the duct work onto the ceiling. Drill a hole through the center of the traced circle. This mark will help you determine where the air vents will go. You will need to do this for the supply side -- where the air comes out of the unit -- and the return side -- where air reenters the furnace.

Locate the areas in the floor above the basement where the air vents will go. Make the hole 3 inches away from the wall and between the floor joists. Cut out a hole the size of the duct work with a jigsaw. Slide the air vents into place.

Connect the sections of duct work together with duct tape to hide the seams. This prevents air from escaping the system.

Place a metal duct strap around the air ducts in the wall and hammer them in place with 1-1/4 inch nails. Support the duct work every 5 feet with a strap if it is running vertically and every 6 feet if horizontally.

Cut a sheet of batting insulation to fit around the air ducts in the wall to insulate them and prevent heat loss. Use the best insulation for your part of the country. Your local building department will have literature on what kind of insulation you should use. Batting will wedge in place, or you can apply construction adhesive to one side of the insulation to hold it in position. Batting that has adhesive already installed on one side is also available.