Tips for Adding Ducting for your Flooring


Having a heating duct in the flooring of your house would help increase the circulation of your room as well as adding heat to a room, which is not designed with a heater. For those of you who only wanted to add ducting to your existing floor, you can simply do it on your own by using a pair of gloves, safety glasses and a few specialized tools that you need to use to complete the task. However, in order for you to maintain a balance system inside your home, it is recommended that you seek advice from an expert HVAC engineer who would be able to provide you with assistance in designing the size, installation and maintenance of your new ducting system. Below are some tips that can help you whenever you decide to add ducting to the flooring of your house.

To add ducting for the flooring, you need:

  • Duct piping segments
  • Starting collar
  • Register boot

Adding Ducting in the Flooring

How to Add Ducting in the Flooring

  • First thing that you need do is to find the starting collar and mark around it. The starting collar should be having tabs around its perimeter which is on the extended plenum and the main duct or the box is on top of its central handler.

    Always double check with your local authority relating to building codes because most of the building codes requires you to have insulation whenever you want to make a new ductwork. In order to handle this type of code, you need to use blanket insulation and also duct tape.

  • Next step that you need to do is to drill holes in the corners and also along the collar outline long sides on the plenum side.
    • You can use a jigsaw that comes with a metal-cutting blade to perform the above step.

    Make sure to wear gloves and goggle as safety precautions whenever you are cutting or using duct materials.

  • Once finished, you need to set the collar into the hole.
    • Then, bend the tabs next to the plenum’s inner wall using pliers.
    • After that, you have to twist or drill three or four holes via the plenum’s side and a tab.
    • You should be using an awl or even use a drill bit which has smaller diameter than your sheet metal screws in order to create your pilot holes.
  • Then, you need to screw the collar along with the plenum by using sheet metal screws.
    • You can also apply a bead of mastic around the seam so that you would be able to cover the screws.
    • Next thing to do is to cut halfway across a strip of fiberglass membrane with at least 1-inch intervals. Then, you need to wrap the membrane around the collar while the tabs should be splayed out next to the plenum in order to smooth it into the mastic all the way surrounding the collar.
  • The round duct segments need to be unpacked by separating the segments and slipping the seams along in each of the segment.
    • You also need to snap the hooked sides simultaneously along each of the segment in order to form a seam.
    • Make sure that you leave one of it unassembled to be used for the final fitting.
  • After that, you need to lay the duct segments out on your flooring located below the area amid the floor joists that you propose to use for their run to the floor vent above.
    • This should be accompanied with crimped ends which points to the direction of the airflow.
  • Then, the crimped sides need to be slide inside the plain ends.
    • The segments should be secured by using sheet metal screws.
    • You have to apply mastic around its exposed end before you proceed to wrap it up using uncut fiberglass membrane.
  • One end of the duct strapping need to be tack high enough on your floor joist with at least 2 to 5 feet using roofing nails.
    • It is recommended that you seek the help from a friend for holding the duct when you attach one end onto the starter collar.
    • The starter collar should be attached as with the other segment joints.
    • The duct needs to be raised and you have to nail the strapping onto the opposite joists in order to hold it.
  • After that, you need to locate the floor register from the wall. It should be between 1 and 2 feet from it.
    • Next, you have to go to the basement and drill a hole right in the center of the channel amid the joists. It should be at least 1 foot away from the sill which is the foundation for the wall.
    • Then, on the upstairs level of the basement, you need to match the floor grille to the center hole. If it is necessary, you need to adjust the spacing before drilling a hole inside each of the corner in order to create guides that define the parameter of the hole through your flooring.
  • The next step is for you to slide the register boot up via the flooring before you can proceed to nail the sides in a horizontal way into the floorboards.
  • The unassembled duct segment need to be cut accordingly with its length should be able to fit between the register boot and the duct.
    • It should be rolled together around the crimping.
    • Then, you need to hook its seam and ease it into the bottom of your register boot.
    • Both ends need to be secured by using screws, mastic and tape.

    Always remember that whenever you want to add ducting in your flooring,

    • You might require a return duct for your heating and cooling duct in order to bring back the air to your furnace or air conditioner. These kinds of ducts are usually made similar to your other duct but its registers are located on an opposite wall and bended or curved sections reach up into the wall between the studs.
    • Always locate your branch starter collars on the side. It should not be on top of the plenum.
    • You will find that some of the duct segments require crimping and some of it are lock in place. Therefore, you must always have available stock of mastic and tape in case you require using them.
    • You must also ensure that you check the airflow of your new ductwork using an anemometer. This is to provide efficient heating or cooling of your new ducting and it should always be equivalent to the airflow which is normally measured in cubic feet per minute or cfm. It should also be similar between your existing duct as well as the new ducts.

Image Credit:

Flickr CC