Framing Around Ductwork When Finishing the Basement

Framing around the ductwork in my basement had me completely and totally stumped. The key to wall framing for your basement is visualization. If you can visualize what the finished wall needs to look like then you are half way there.

It's a skill that takes some time to develop but then is very easy to repeat. Even though I had already framed a few rooms for my basement I need some help from friends to wrap my brain around how to handle framing around the ductwork.

Be sure to check out my "super tip" at the end of the post for a solution to a noisy pipe problem that must be solved before you close up your ductwork framing with drywall.

framing around ductwork

Wood framing around duct work for a finished basement. Duct work framing is often called a soffit or soffit run.  Which is French for - a type of ceiling that can be a pain in the ass.

What is "Ductwork" and Why do I need to Frame It

Okay, so here's the deal. The ductwork I'm referring to is the main line (a metal box) that carries the cold and hot air from your basement HVAC area to the rest of your house.

In my house I have 2 main ductwork "lines". One goes straight up from the HVAC unit and delivers air to one side of  the house. The second travels across the basement to the other side of the house and then up through the ceiling to the upper floors.

It's this second ductwork line that crosses your basement ceiling that you'll need to frame. Once it's framed you can cover it with drywall. In essence it become's an extension of your ceiling.

Why is Ductwork Framing Difficult ?

Framing around ductwork is difficult to get straight. It's a long and short expanse of wall that is front and center visually. The biggest mistake people make is that they just throw a wall up there and it ends up looking really wavy and uneven. Sloppy.

You need lumber pieces that are as straight as possible. But that's only half the battle.

Even with perfectly straight lumber you need to take extra caution in framing the wall straight so that it looks professional once it's finished. With a regular wall you can get away with a  few mistakes. When framing around ductwork I would be more cautious and deliberate.

Steps for Framing Around Ductwork

These are the steps that I used. I'm sure there are several different ways.  I can claim honestly that the professional drywall company I used said my ductwork framing was one of the best jobs they'd ever seen. That was good to hear since it took me about 2 weekends to get right!

Step 1 : Build "ladders" on the ground. 

  • The look like mini-ladders (see pic). Build them using 2x2 lumber instead of just 2 x 4. You may have to make your own or have Home Depot cut some for you as the big box stores don't always carry 2x2.
soffit framing for a finished basement bathroom

Soffits are not just for framing around duct work.

Step 2:  Secure the ladders to the ceiling

  • Use screws not nails.  I promise you, you will be moving and adjusting these ladders to get them as straight as possible.  Nails are difficult to remove.
  • Make sure the tops of the ladders align.  Don't worry about them not being lined up "in" or "out" that will fix itself when you hook them to the cross beams.

Step 3: Install the horizontal support "railing"

  • The cross beams will attach to the inside of your ladder on one side and this cross railing (as I call it) on the other.
  • If there's no wall on the other side, like a hallway scenario or an exposed beam, then you just build a second ladder instead of a railing.
  • Again, I recommend screws, you'll have much more control. An impact driver helps tremendously here, you know I love those.
soffit with air duct extension and framing support for finishing a basement

Soffit with air duct extension and framing support for an air register

Step 4: Install the cross beams

  • Make sure the bowed part of the beam points up into the ceiling cavity and not down.  The cup of the bow can be covered by drywall. If it's bowing downward your ceiling will look wavy.
  • Be sure to add an extra beam or two around the location of any duct extensions so you have some wood to anchor the screws of your air grill.

4 Keys to a Great Ductwork Framing Job

  1. Spend some time visualizing the final framing before you start. If you were to install the drywall, mentally walk through where it would attach to the wall and the ceiling.
  1. Use the straightest wood pieces possible.
  1. Make sure your ceiling beams are as level as possible and that their intersections with the "ladder" section of the walls is as close to 90 degrees square as you can get. A smidge off is ok, you don't need perfection, but the closer the better.
  1. CLAMPS!   Use clamps to pull the ladder sections into alignment as you are installing the cross-beams. The clamps will hold pieces perfectly while you secure them with screws. Oh man, I do love me a good set of clamps.

Jason's SUPER TIP !

loud noises from pvc pipes rubbing wood

Wrap the pipe at these points with some felt contact paper and the noise will go away.

Do your PVC pipes make an annoyingly loud noisewhen they rub against the underside of the ceiling joists as they expand and contract? Mine did and it drove me nuts!

Before you close up the ductwork with framing and drywall, loosen the "J" clamps that secure the pipes to the ceiling joists.

Wrap the pipe with felt contact paper wherever it touches the joists. The noise will be gone!  Oh, you're welcome.

Finishing your basement on your own is a big project with a lot of challenging hurdles. Framing around ductwork is one of the first true tests of a good framing job.

basement finishing jason

Be patient. Take your time. Enjoy the process and challenge that framing presents. I hope this article from an amateur viewpoint helped you out. Let me know if you get stuck by sharing a comment below.

Cheers - Jason


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Questions and Comments

Click here to ask a question or leave a comment.

    • says

      Phil - Thanks, hope it's been helpful. I did, just to stay consistent. But if it was off I didn't worry about it to much. The vertical only got drywall nails at the top and bottom anyway. The bottom part the 2x4s were laid flat so it was pretty easy for the drywall guys to hit. -jason

  1. Kevin says


    Where did you get the register extension? I am running into same issue with register already in place but need to create soffit around it. Went to a couple of large home stores and they did not have it. What is the name of this and where can it be purchased.


  2. Dan says

    Great site! love the pics... quick question, is there a minimum spacing/clearance requirement between the HVAC ducts and the bulkhead encasing material (sheetrock)? Dan

    • says

      Thanks Dan - As far as I know there are no minimums. You may want to ping your local building department but I haven't heard of a minimum. Anyone else? Feel free to chime in.
      - Jason

  3. Rylan says

    Is your book available in a hard copy? Really do not want to carry laptop around while doing construction. Thank you.

    • says

      Sorry Rylan - It's only available as an e-book right now. It's not something you'd really carry around with you while working. Yes, it has some step by step, but it's more about planning, design decisions, permits, things to watch out for, how to save money etc. The videos are step-by-step and are free with the book (as of Mar. 2013) but obviously you would need a laptop to watch those. I'm shooting to get to hardback by the end of the year. If anyone knows of a publisher that wants to pick me up or an inexpensive high quality publish it your-self option - let me know. -Jason

  4. Steve says

    Has anyone attached 2 X 4 directly to steel beam with ramset? I am finishing my basement and was thinking it might be easier just to nail right to steel beam and not have to build a ladder.

    • Vincenzo says

      Do it yourself. Refer to the ladder frame it's easy to build on the floor and easier to attach to ceiling

    • says

      Yes, if your floor joists (the ceiling above you in the basement) is parallel to what you want to frame then you just need to add some blocking so you have something to nail into. Hope that helps. - Jason

  5. Chris says

    Great website Jason! Question for you, pertaining to ceiling... I have seen some basement ceilings (open joists, ductwork, everything exposed) that are painted straight black or white (I'd lean towards white for the lightening effect). Any thoughts on finishing the ceiling this way, and type of paint/application? I'm assuming a friend with a sprayer would be best? =) I'm not sure how long I'll be in this current house, and would like to leave my options open for putting new/different lighting in in the future, thus avoiding drywall for now.

    • says

      What up Chris - Honestly, a small part of me wishes I had left my basement ceiling open and just painted it. I think it looks cool. You can always drywall it later if you change your mind. You can still put in the normal can lights, wiring, everything, there's really no difference. I have two pictures on my Pinterest board - one with black ceiling and one with white. I prefer white, but the black looks pretty cool too. Check it out.

      You would definately have to spray paint it. So that would add to the cost. I think a normal paint would work fine. - Jason

  6. Dave says

    Hi Jason,
    I need to put a wall with a door crossing under duct work. Do you have any suggestions/concerns?

    • says

      Yo Dave -
      Well, it will be a fairly short basement wall I'm guessing. But, there's no reason you can't frame a wall under the ductwork. And yes, that wall could have a door. You just need to frame around the ductwork, which you would have done anyway to attach drywall. So yes, as far as I know you're good to go there. - Jason

      • Vincenzo says

        You might have to cut the bottom of the door and jamb to fit it depending on your height. Keep in mind 80 inches is standard

  7. Steve says

    Hey - great advice. Thanks for sharing this! You mentioned using screws instead of nails. What size/type of screws do you recommend?

    • says

      Hi April - There may be, that's something that would be location specific. My area did not have a prescribed distance. I framed up around the soffit about as close as I could and passed inspection with no problem. - Jason

  8. CHRIS says

    Hi Jason, great site you have here. As I've been looking around the internet trying to figure out what I can/should do myself vs. when to hire a contractor; I did have a question that I have yet to see asked anywhere else-

    If I want to install additional intake/outtake ducts from my furnace (to service the different rooms in my finished basement), should I get this done first? Or should I frame the rooms beforehand to get a better idea of positioning?

    thanks in advance!

    • says

      Hi Chris - You can do the framing first. For me, it was easier to visualize the new register locations once my basement framing was complete. Great question! - Jason

  9. Mike says

    Appreciate the ease of instruction and the tips. I am finishing the basement with a bedroom, furnace room, cold room and open concept media/games room. I used Roxul sound bats to insulate the bedroom (it is right under the kitchen) and the furnace room (it also has the central vac). I am considering the same for the ceiling in the media/games room but my issue is the darn ductwork and support beams. I think when they built the house they never had any intention of finishing the basement because I have two support beams and three duct runs which will complicate finishing the ceiling. What are your thoughts on insulating for sound around the duct wok? Possible? Worthwhile? What would you recommend?

    • says

      Hey Mike - My thought would be that it's not worthwhile. Most of the sounds travels from floor (the floor above your basement, the kitchen) to the floor joist then to the drywalled ceiling of your basements. I added insulation for sound proofing in some of my ceiling bays - and it works okay, but not fantastic. The space around the ductwork is so small I just don't think it would have a big impact.

      The real bummer is that when you first put up the insulation your basement is going to be crazy quite. That's because without the drywall ceiling and walls the sound from above just drops off the bottom of the joist into thin air where it can't travel. It's only when the drywall is added that it comes back.

      For the media room - you might consider - padded drywall channels for installation - they can dampen a lot of the sound. - Jason

  10. Dave says

    I want to maximize ceiling height, can I use 1x4s instead of 2x4s? Should I adjust spacing between the studs/furring strips if I use a thinner piece of wood?

    • says

      Yes, 1x4s will work fine. Spacing should still be fine. It's not support a full sheet of drywall (this is duct framing right?) so there shouldn't be any sag. - Jason (ps. I just turneded my 2x4s sideways - same result)

  11. David says

    Hello Jason. I'd like to build a bulkhead over a long run (25') of ductwork that is 6' across. I'm concerned that the 2x2 cross pieces will sag, especially with the weight of the drywall. I'm hesitant to screw into the duct for anchoring. What is the professional method of doing it ? Many thanks.

    • says

      Hi David - Well definitely don't screw into the duct work. Yes, a six foot span is too far. You'll need some horizontal bracing. You basically build a ladder support vertically on each side of the duct, then attach horizontal 2x4 or 2x2 to that "ladder", spacing them 16" on center. The drywall guys can then attach the drywall to those supports.

      Hope that helps. - Jason

  12. Don says

    Why do you specify that the support beams should connect below the horizontal support rail instead of on top?

    • says

      Hi Don - That was for my situation. They could also be on top. As long as they are level. Good question. Good luck! - Jason

  13. ray says

    A previous owner framed and drywalled around duct lines and center beam. The drywall/paint shows moister. The existing framing is too tight to wrap duct with insulation. Would adding some vents to make it a " conditioned space " be acceptable.
    Thank you.

    • says

      Hi Ray - Hmmm.... I'd be worried/curious about why there's so much moisture. I suppose a register could help a little but I'm skeptical. I guess I'd tear it down, monitor for a few weeks and see which parts are causing the issue - then go from there. Sorry I don't have a more definitive answer. Send me a picture or two once you've remove the drywall. - Jason

  14. Bryan says

    Howdy! How are the cross supports connected to the ladders? Toe nail, Jedi power, or something else? I don't see any nails or screws in the photos. :)

    • says

      Hey Bry - Well I tried Jedi power but apparently the force is weak with me. I used screws. I could have used a nail gun but I wanted to be able to easily remove the screw in case the ladder wasn't perfectly aligned. That's why you can see the fastener, the screws are set into the wood a bit. Highly recommend the screws for the ladders, nail gun for the regular framing. - Jason

    • says

      Good question, tough to answer. The key is that you don't want the beam to sag once the drywall is installed. My guess is around 6 feet or so??? At twelve foot cross with no support definitely sags, even an 8 foot beam has a little bend. - Jason

  15. Donald McGowan says

    I have a return duct that is against the one side of my wooden center beam the whole length in the basement and I can't fit anything in between to insulate. What do I do? On the other side of the wooden beam is all the electrical wires going from one side of the basement to the other. My second Question is, I feel air in certain parts of the ductwork leaking out, do I use the metal tape to patch them before putting the board up? I would think so using common sense, but I had to ask. I also noticed your pictures don't have any insulation around the ductwork, Is that ok not to insulate before you close up the soffit with drywall?

    • says

      Hey Donald - Yes, it's okay. You don't have to insulate around duct work and I personally didn't do that either. As for the leaks, yes duct tape, that's exactly why it was first invented- to help seal the ducts! Have fun with the basement! Cheers - Jason

  16. Amanda says

    What do you suggest for framing ductwork that is right over a doorway? There's only like 1 inch of clearance between the top of the door and the duct. Is our only option to cut the door down? Because if we do that then it will be too short for the door frame. We're totally lost on what to do. The previous homeowners just painted the ducts but we would really like to finish them off.

    • says

      Yup, you just gotta trim the trim and/or cut down the door a bit. I had the same issue, it actually turned out looking just fine - no one even notices. - Jason

  17. Kyle Engen says

    Hi, we had a sewer vent stack removed in our basement. This left a protrusion extending about four inches out into the room on the floor. How can we frame around this without creating a trip hazard?

    • says

      Hey Kyle - Well, this may sound obvious but can you trim it down to floor level? If there's concrete - you can buy a sweat little angle grinder and knock it right down (just take my advice and wear a dust mask - and open the windows) - Jason

  18. Sean says

    Jason, I saw the information about framing around the ductwork, which was great by the way, but do you have any information on adding to the ductwork so there are vents for the finished basement, i.e., I want to make sure I have proper ventilation fora/c and heat once i'm finished the basement.

  19. says

    Hey Jason! I have zero experience framing and although I'm learning a lot, I'm worried about doing this part on my own. I'm tempted to just hire this part out, but it seems like this is essential to getting the basement to look well done. Do you have any tips for finding a good framer?

  20. Savreet says

    Hi while doing a framing in basement just under the duct
    Is it advisable to use nails to go through the frame wood into the duct or no???

    • says

      That's a big ole "NO" Savreet. Legit question - I would have wondering the same thing. You do not want to puncture the duct work in any way - except to attach a new register or something related to duct extension. - Jason

  21. Monica says

    We began framing and closing in the duct work in the basement now we are seeing condensation is it because we havent framed it all in or because we need more insulation?? Need to figure out if we continue or start over

  22. Dennis says

    Hi Jason, I have a ductwork run of about 30' in length; can the ladders be made in sections to make hanging them a bit easier?

    • says

      Hey Dennis - Yes! There's a lot of flexibility in how you build the framing - in the end it's all getting covered in drywall. Just keep it straight and level and it will look good ! - Jason

  23. Terry W. says

    Thank you for recommending using screws to build the soffits. I almost used the framing nail gun but I remembered you saying something like "Use screws because you are bound to make a mistake or two building soffits" Wow, were you right. I did a simple math error and had to take down two hours worth of work. If it had been nailed it would have been a disaster.

    • says

      You got it! It's the tiniest tips that can save hours and hours of work, lots of money and personal injury (due to extreme frustration!) - Jason

  24. Chris says

    Thank you for your great article. I will plan on demo for my future man cave for the purpose of extensive soundproofing which will include whisper clips, 7/8's hat channel, 2 layers of 5/8's X sheetrock with a thick layer of green glue in between. My walls will be heavy! I have 16 years of drywall experience and have always seen HVAC framing 2 x 2. But I'm thinking I will need to do 2 x 4 for the excess weight. The sheetrock casing as of now measures 21" H and 17" underneath. Can I just build the framing as If I was framing a traditional wall, especially since the whisper clips do not have the capacity to attach to the wider 2 x 4 in the side position.
    I hope this makes sense.

    • says

      Hi Chris - From what I understand there are no special framing requirements to prepare for using "whisper clips", green glue, or an extra layer of drywall. It sounds like you have a great sound-proofing plan! - Jason

  25. JR says

    Great site! One quick question... For the horizontal support "railing", it appears that you are using a 2x4. Do you think a 2x2 would also be sufficient? I'm wanting to get the bottom of the bulkhead as close to the ductwork as possible, and by using a 2x2, it would rise up the bottom of the bulkhead up a few inches. Any strength/support issues with this?

  26. Chris says

    I am finishing my basement and I have heat ducts running in between some joists. I am insulating the ceiling between the basement and first floor. Do I need to insulate around the ducts?

  27. says

    Can I simply say what a comfort to find a person that genuinely understands what
    they are talking about on the web. You actually understand how
    to bring an issue to light and make it important. A lot more
    people ought to read this and understand this side of your
    story. I was surprised that you are not more popular because you most certainly have the gift.

  28. Chris says

    Jason - thank you for the article and comment about PVC and potential noise. You mentioned contact felt paper. It seems like there is a link to Amazon (contact chalk board coverying). Is this the material your recommend wrapping the PVC pipe to avoid any noise? I want to make sure I get the right product. Many thanks!

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