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Running Ductwork from the Basement to the Second Floor in 4 Steps

Wondering why your second floor is so hot even if you turn on the cooler? The culprit behind this annoying heat is your ducts. If your ductwork reaches the second floor, it’s bound to get hotter. 

Thinking of running ductwork from the basement to the second floor?

Make a hole in the main duct to run a duct from the first to the second floor. After that, put in the new ducting. This will lead to the second floor’s floor-level heat register.  Finally, seal your ductwork properly to maintain the heating.

Of course, you need to do it carefully by following the right steps. Things may easily go wrong. It’s possible that you’ll wind up destroying the entire system.

This is why we noted down a detailed guideline below. 

To know more, keep on reading!

How To Plan Setting Up The Ductwork

It’s essential to visualize or plan your ductwork before you set it up. This also includes when running ductwork from one floor to another. Planning it out beforehand helps you understand how many extra tools you need and ensures a smooth installation. 

Start the planning by deciding where you want to attach the ductwork on the second floor. It could be hidden beneath a closet or in an out-of-the-way corner. However, it should be near a basement ceiling joist.

After you find a suitable place, get your measuring tape. Measure the area from the main duct to the suitable place. It doesn’t need to be accurate. An approximate value would do. Once you get the numbers, buy your tools in accordance with that requirement. 

Step-by-Step Guideline To Run Ductwork To Second Floor

Working with ductwork can be a bit daunting. Whether you want to insulate ductwork in the basement or run it to the second floor. With some guts and guidance, you can still do it.

We’ll give you the direction that you need, down below. –

Required Materials 

To carry out this tutorial, you need the following tools. You may already own some of them. If not, make sure to run a quick errand before you start your project.

  • Straight Duct Tubing
  • Metal Duct Hangers
  • Transitional Fitting
  • Saw
  • Sheet-metal Snips
  • T-Fit Duct Tubing
  • Heat Register
  • Studs
  • Marker
  • Mastic
  • Duct Tape
  • Drywall

Got your tools ready? Great! Let’s jump into the steps.

Step 1: Locate And Cut Main Duct

First off you need to locate the plenum or main duct on the first floor.  Next, select a suitable location on the second floor to run the ductwork. It could be beneath a closet or in a less-used region of the house. But it should also be near a basement ceiling joist. 

On the main duct, draw a circle the same size as the duct collar. Make sure to assemble the circle so that it faces the second floor. Then use sheet metal snips to cut off the circle you drew. You can also use a Dremel to cut the ductwork

Make sure to use caution when handling your fingertips. You can wear gloves for extra safety. 

Step 2: Run New Ductwork

Secure the duct collar around the primary duct opening. Make a hole in the floor just big enough to fit the ductwork through. Secure the new ductwork to a joist in the basement. Wrap a hanger around it and secure it to the joist in this manner.

Continue joining ductwork sections until you reach the first-floor ceiling. Using the saw, make a hole in the ceiling. Make sure to be careful and accurate. Similar to when you cut ductwork with a jigsaw. But don’t cut through the second floor’s ground level just yet.

Step 3: Install The Ductwork

You need to install the ductwork in the ceiling. With a hanger, fasten it to an adjacent joist. If you want the new duct to run into multiple rooms use a T-fitting piece of ductwork. You’ll be able to attach new ductwork horizontally as a result of this. 

Cut a hole in the second story’s ground level where you desire ventilation. For this step, you’ll need a saw. Make a large enough hole in the duct beneath the floor to enable a transitional fitting. Connect the fitting to the hole in the floor and tighten it. A heat register can be used to cover the hole.

Step 4: Conceal Ductwork

Next, you need to seal any open ductwork. Apply duct tape to the exposed duct and then use mastic to seal it. Make sure to use quality duct tape for the job. Here are some you can try. –

Product 1
Product 2

With the help of these tools, you’ll be able to seal your ductwork without any loopholes.

Conceal the duct that connects the first and second floors. Metal studs should be used to round the duct. These will act as a structural foundation for drywall. It can also cover the duct and create a new internal wall using suds.

By following the above-mentioned steps, say goodbye to hot summer days. Of course, make sure to clean your air ducts every now and then.  You can have cooler days for your second floor with your new ductwork. 


Question: How far can you run ductwork?

Answer: You can run ductwork 10 or 20 feet of effective length if it is of good quality. However, if you go with the smooth mitered elbow, you’ll wind up 75 feet.

Question: Can you run duct through floor joists?

Answer: Yes, you can. Duct chases for insulated, flex, air-sealed metal or fiberboard ducts can be made in floor joist cavities.

Question: Are floor or ceiling vents better?

Answer: Both vents act better than the latter based on your requirements. Ceiling-mounted vents provide more cooling capacity. So if you prefer cooling more, ceiling vents are better. For better heating, floor vents are better. They provide better heat distribution.

Final Words

You know exactly what to do for running ductwork from the basement to the second floor. So you don’t need to spend extra cash on hiring professionals. 

We hope you found this guide easy to grasp. We tried to make it as easy as we could for your better understanding.

Thank you for being patient and staying with us till the end.