How to Expand Duct Work to a Garage
- 1). Make sure that there are no gaps in insulation or improperly sealed openings that can cause heat loss. Using insulation, such as pink fiberglass with a plastic membrane, ensures that all spaces behind drywall are filled. In areas around windows or doors, use a caulking product to seal any cracks or holes.
- 2). Extend the main trunk, sometimes called a plenum, into the garage. The main trunk is the rectangular ductwork running from the heating unit, such as your furnace. This runs along the ceiling suspended from the ceiling joists. Remove the end cap on the end of the trunk with a power drill. Remove the screws with the utility knife so that you can remove joint tape, then add more duct horizontally. If you have to extend vertically, extend the trunk horizontally to sit under or above a wall in the garage. Attach a take off to the top of the trunk by cutting an opening with the snips, then attach a circular duct called pipe that will run to the wall where you will be installing the duct. Fit the pipe into a duct boot, and attach the wall stack to the desired height. This will allow you to run a wall stack up vertically within the wall. Use aviation or tin snips to cut the pipes and ducts to length.
- 3). Install the registers or end boots in the garage. This is where the hot air will come out of through the wall or floor, so ensure that you have cut out an opening in the drywall or plywood with a power router.
- 4). Ensure that all ducts and pieces are attached together firmly with duct screws and joint tape. Hold the unsecured ducts together and drive three to four screws, distanced equally apart, with the power drill around the duct. Use the utility knife to cut a strip of joint tape to cover the joint and screws completely.
- 5). Make sure that you also have cold air return intakes installed to return air to the furnace's cold air return. With these intakes, there will be enough air ventilation to keep the garage properly heated and they will also keep the air quality from suffering.