How to Hide HVAC Ductwork with Drywall
DO NOT JUST SCREW DRYWALL RIGHT INTO THE HVAC.
Exposed heating and cooling ducts are somewhat popular these days as a way to lend an industrial touch to décor (think of Chipotle restaurant’s interior design for example), but traditionally it’s best to hide ducts using what’s called a soffit. Drywall should never be attached directly to a HVAC duct, as inserting screws into an HVAC duct would create holes, compromising the efficiency of the HVAC system, and the weight of the drywall could cause the ductwork to sag or bend, which is why building a soffit is a necessary first step in this process. By inclosing the duct with a soffit, you are not just making the HVAC duct look better; you are making your system more efficient by providing insulation for your ductwork.
Aside from the drywall all you’ll need for this project are some 2-by-2 boards, some 1 ½ inch drywall screws, and your tape measure and power drill to apply screws.
Start by measuring the length of the heating duct you intend to enclose, and cut two of the 2-by-2 boards to that length. Then attach the two 2-by-2’s to the ceiling joists parallel to the duct. I recommend leaving a bit of space, up to two inches, between the wood and the duct. You can also butt the boards directly up to the duct if you wish to make the soffit as small as possible, but it’s recommended to leave a bit of space to allow the duct to expand when it heats up.
Now that you’ve got your two parallel boards in place on the sides of the duct, measure from the bottom of one of the 2-by-2’s to the bottom of the duct. Subtract 2 ½ inches to account for the horizontal board that will make up the space on the bottom later and you’ll have the length for the vertical boards needed to make up the sides of the soffit.
Now return to the board you screwed onto the ceiling joists parallel to the duct and mark out 16 inch centers, which is where your screws will go for your vertical boards. Cut enough 2-by-2’s to account for each mark, and screw these boards vertically to the top horizontal board at each mark. Repeat this on the other side as well.
Now you should have two horizontal boards parallel to the duct, and vertical boards attached to these every 16 inches. Screw another 2-by-2 board along the bottom of all the vertical boards, forming what looks like a ladder on its side. Repeat this on the other side of the duct.
Your supporting structure is in place; now you can measure and cut drywall for both sides of your new soffit. Once the drywall is measured and cut, hang it by placing screws through the drywall and into the studs you created by placing your vertical boards every 16 inches.
The last step is to measure and cut a piece of drywall for the bottom of the soffit. When measuring this bottom piece, make sure the drywall extends enough to be flush with the edges of the drywall you already hung on the sides so that a perfect box will be formed by the edges. Cut the drywall and screw it onto the bottom of the soffit by placing your screws to that they enter the bottom horizontal boards on each side, and you’re done!
You should now have an enclosed and insulated heating duct! You’re now ready to move on to taping and painting your drywall in whatever way will look best for your home.