How to Make a Flange for a Dryer Vent

Cut a square piece of sheet metal 8 inches wider than the diameter of the dryer vent pipe with a pair of tin snips. This gives you enough flange on each side of the dryer vent to fasten it against the wall.

Place the end of the dryer vent duct over the center of the sheet metal. Trace around the dryer vent duct onto the sheet metal with a pencil. Make another trace line 1/4-inch outside the first line. The second line is your cut line.

Drill a 1/2-inch hole into the sheet metal inside the tracing with a 1/2-inch drill bit. Remove the bit from the drill and insert a 1/4-inch drill bit. Drill two holes, evenly spaced, along each side of the flange. The holes should be 1 inch from the edges of each side.

Cut the tracing hole out with a pair of tin snips, using the 1/2-inch hole as a starting point. Measure the circumference of the inner hole with a tape measure. Cut a length of grommet to the measurement with a utility knife. Grommet is rubber with a groove in the center and is available at hardware stores.

Insert the groove of the grommet onto the edge of the inside hole. Push the grommet over the edge and completely around the hole. Cut four more pieces of grommet, one for each side of the flange. Install the grommet over the flange edges. The grommet covers the sharp edges of the sheet metal, reducing the possibility of cutting yourself or the dryer duct.

Slip the flange over the dryer vent pipe and against the wall. Drill holes into the wall with the 1/4-inch bit, using the holes on the sides of the flange as a guide. Insert plastic anchors into the holes as far as possible with the flange in place. Thread screws into the anchors and tighten with a screwdriver to secure the flange to the wall.