Build the cabinet where you are placing the counter stove top. Use a jigsaw to cut vent holes into the cabinet where the main retractable downdraft system will be placed.
Saw the vent slot into the bottom of the cabinet, about 3 1/4 by 10-inches wide for a square vent, or 6-inches round for a round duct pipe.
Attach the blower motor in the cabinet. Set the power junction box in the rear corner in the cabinet on the right or left side.
Run the duct work through the vent and down into the floor using 6-inch round metal pipe.
Run the piping along the floor joists toward the nearest wall of your basement if you have one in your house. Place a 90-degree elbow on the pipe from the cabinet bottom.
Put in three sheet-metal screws to secure the pipe.
Set in a long run of round pipe toward the wall. Cut a hole in the wall and extend the pipe out.
Attach a wall cap on the end of the vent. Seal around the pipe with foam insulation.
Place piping for kitchen island stove tops under the concrete floor. Do this before tiling, while you have access to the floor without breaking up tiles.
Dig the trench for the pipe, using a jackhammer if you have to go through concrete.
Lay in 6-inch PVC sewer pipes as the main run for any piping below ground. Place transition couplings when switching from the PVC pipe to the metal duct pipe.
Pack gravel or sand around pipe before sealing up the floor with concrete.
Attach the vents to the retractable vent system placed in the back of the cabinet. Secure the brackets to the cabinet with screws.
Install the counter stove top.
Things You Will Need
- 6-inch round metal duct pipes
- 90-degree elbow pipes
- Sheet-metal screws
- Foam insulation
- Gravel or sand
- Decide on the best retractable downdraft vent system for your kitchen. You can choose between an internal blower motor or an exterior-mounted blower based on the counter stove type you have.
- If you cannot go through the wall, run the vent pipe between the studs of the wall to the roof.