How to re-route hvac ductwork to remove wall

It is important to learn how to relocate ductwork to knock down a wall to ensure that you will not end up compromising your equipment and to continue enjoying the comforts of your home to the fullest.

Why do you need to re-route HVAC ductwork to remove wall

The ductwork for heating and air conditioning systems is made up of supply ducts in charge of dispensing air and the return ducts that are responsible for drawing air.

These two types of ducts terminate at the grills on the walls or ceiling of a room. There are times when these ducts can be abandoned in the meantime when knocking down or removing a wall. However, if it is important for the heating or cooling system to still be in operation during the work, it is crucial that you know the necessary steps on how to re-route HVAC ductwork before you demolish the wall.

While you can always pass on the job to professionals, you can actually work on relocating the ductwork on your interior walls that bear weight. You just need to use some parts that you can easily find and buy from local air conditioning supply stores and home centers.

Materials you need to relocate ductwork to knock down a wall

You need a few things to get started in relocating ductwork when removing a wall and these include the following:

  • 1 1/2-inch drywall screws
  • 2-by-4-inch lumber
  • Circular saw
  • Cordless or power drill
  • Duct hanger strap
  • Duct tape
  • Flexible duct (optional)
  • Framing nails
  • Hammer
  • Nail bar
  • Nut driver attachment
  • Reciprocating saw with drywall or wood cutting blade
  • Screw-tip attachment
  • Self-tapping duct screws
  • Sheet metal cutters
  • Stepladder
  • Utility knife

Important tip for relocating ductwork

The large return-air grills close to the floor can often be found near a heating unit without any associated ductwork. All you have to do is to remove the grill first before you demolish the lower portion of the wall.

How to prepare for ductwork relocation

  1. Place the stepladder at a grill’s area. Loosen then remove the pan nuts or screws from the front portion of the grill using a cordless or power drill with the correct tip attachment. Make sure that you put all the nuts or screws and the grill in a safe spot since you will still need to use them later.
  2. Remove all the screens within the rigid duct that hold the wall framing and the square end together.
  3. Prepare the reciprocating saw with the suitable blade for drywall finish or wood paneling. For walls, you need to make some vertical cuts at both sides of the opening of the grill, starting at the lower portions of the opening then continuing up to the ceiling. Use a hammer and a nail bar for removing the wall finish section. You can skip the step if the opening of the grill is located at the ceiling.
  4. Search for the corresponding flexible ductwork connecting to the rigid duct at your attic area. Proceed to loosening and removing the screws that are securing the duct straps and the attic framing together. The straps can be removed afterwards.
  5. Disengage the connection where the rigid duct’s circular tip and the flexible duct meet. You can do this by using a utility knife to cut away the duct tape if there is any. The duct screws should also be loosened and removed. Pull out the part of the rigid duct from the wall and make sure that you save the piece.

How to relocate ductwork to knock down a wall

  1. Find a location or spot for the grill. It can be on the face of a different wall or it can also be at the ceiling. You can use the rigid duct’s square tip as your guide for marking the hole in the wall finish or ceiling. Use a reciprocating saw for cutting the hole. If ever you end up encountering some framing members, you can change the location either way for the hole to be sandwiched at the center of the members.
  2. Take out a part of the wall framing’s top plates to give room for installing the rigid duct if the grill will be installed on a wall surface. You can use the square tip of the rigid duct as your guide for marking the plates. The reciprocating saw can be used for cutting the top plates to form the duct’s opening. You can now insert the square tip of the rigid duct from above into this opening. This step can be skipped if you will install the grill at the ceiling.
  3. Place the duct in such a way that the open square tip and the hole at the wall or ceiling are aligned. Mark the locations on the adjoining framing for support blocking at both sides of the duct. Use a circular saw for cutting the blocks to the length.
  4. The blocks can now be installed against both sides of the rigid duct. To do this, you can nail the ends of the blocks to the nearby framing using a hammer and framing nails. You need to secure the square tip of the rigid duct at the blocks using screws inside. You can use the holes of the old screws that you removed earlier.
  5. Place the open tip of the existing flex duct in such a way that it will point to the circular tip of the rigid duct. You can have a new portion of the flex duct installed if needed so that the run to the rigid duct can be completed. Use the duct tape to secure and seal this connection to the existing duct.
  6. Connect the tip of the flex duct to the circular tip of the rigid duct using the self-tapping duct screws. You can use the duct tape again for sealing the connection. The flex duct should be strapped to the attic framing at intervals of 4 feet using drywall screws and duct straps. The straps should be cut to length using the sheet metal cutters. Finish off the job by reattaching the grill on the wall surface at the new location.

The Bottom Line

When you know how to relocate ductwork to knock down a wall, you can actually hit two birds with one stone. You can remove the wall for whatever project you might have and at the same time, you can be sure that your ductwork won’t be affected for your HVAC unit to continue working and keeping your home as comfortable as you want it to be.

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