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How to Install an Air Duct in a Suspended Drywall Ceiling – Part 2

Bob Jackson
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by Bob Jackson

How to Install an Air Duct in a Suspended Drywall Ceiling photo tutorial. Mount the new vent boot, install the branch duct takeoff and flexible air duct. This project is continued from Part 1.

Mount the Vent Boot in the Drywall Ceiling

The new Speedi-Boot™ 6″ air vent is set in the drywall ceiling cutout, ready to be fastened to the steel suspended ceiling runners with sheet metal screws.

Speedi-Boot Air Vent in Drywall Ceiling
Speedi-Boot Air Vent in Drywall Ceiling

Speedi-Boot Telescoping Arm Attachment

The Speedi-Boot air vent features adjustable telescoping arms that extend for a perfect fit. The arms have factory-installed nails for nailing to wood studs or trusses, however nails won’t work with the steel ceiling runners. Instead, I will fasten the arms to the steel runners with 1/2″ sheet metal screws using the factory-made pilot holes. Simple!

Speedi-Boot Installation with Sheet Metal Screws
Speedi-Boot Installation with Sheet Metal Screws

Each of the four arms are secured to the steel runners with a single sheet metal screw. Here’s a close-up of how the telescoping arm is fastened with a 1/2″ sheet metal screw to the suspended ceiling steel runner.

Speedi-Boot Telescoping Arm Installation with Sheet Metal Screws
Speedi-Boot Telescoping Arm Installation with Sheet Metal Screws

Install the Flexible Air Duct Branch Line

Slip the inner core of the 6″ flexible air duct over the Speedi-Boot collar and secure with metal foil tape, smoothing the tape for an air tight seal. The 90° vent boot is ideal for situations like this where there’s no insulation, making for direct alignment with the flexible duct to avoid kinks.

Speedi-Boot Flexible Air Duct Connection
Speedi-Boot Flexible Air Duct Connection

Slide the flexible duct insulated outer jacket over the Speedi-Boot and secure with a 36″ long zip tie.

Vent Boot: Flexible Duct Outer Jacket and Zip Tie
Vent Boot: Flexible Duct Outer Jacket and Zip Tie

You can find the 36″ HVAC ductwork zip ties in the vent and duct supply section of most home improvement stores.

Duct Board Take-Off for Flexible Duct

A 6″ inch starting collar is installed for the new take-off in the rigid duct board trunk duct. For details of how to cut the hole and attach the starting collar, see this related project.

Flexible Duct Start Collar in the Rigid Duct Board Trunk
Flexible Duct Start Collar in the Rigid Duct Board Trunk

The 6″ flexible duct is cut to length and attached to the starting collar with metal foil tape and a zip tie in as was done for the Speedi-Boot air vent.

Flexible Duct Connection to the Trunk Air Duct
Flexible Duct Connection to the Trunk Air Duct

View of the 6″ flexible duct routed through the ceiling crawlspace to the Speedi-Boot air vent. Take care to support to flexible duct with wide nylon duct straps and avoid sagging, pinches or kinks that would restrict the air flow.

Flexible Duct Routed through the Ceiling Crawlspace

Overhead view of the new 6″ flexible air duct takeoff from the rigid trunkline ductwork. Notice the 1-3/4″ nylon web duct hanger strap supporting the air duct between the 2×4 wall studs.

Flexible Air Duct Branch from the Trunk Duct
Flexible Air Duct Branch from the Trunk Duct

Flexible duct must be supported with hanger straps at least every 5 feet in suspended installations.

Speedi-Grille™ Ceiling Register Installation

I’m back to the main room in the finished basement to install the ceiling register. Speedi-Boots feature a cardboard dust cover to keep out dirt and paint.

Speedi-Boot Air Vent Dust Cover
Speedi-Boot Air Vent Dust Cover

Remove the dust cover to reveal a pristine air vent.

Speedi-Boot Air Vent Drywall Ceiling Installation
Speedi-Boot Air Vent Drywall Ceiling Installation

Speedi-Boot accepts any standard ceiling register, but I’ll be using the Speedi-Grille™ companion product which features mounting tabs on the back for snap-in hands-free installation. The Speedi-Grille simply snaps into the steel opening of the Speedi-Grille vent boot. This is great because I now have two free hands to install the permanent mounting screws without worrying about the grill falling on my head, dropping a screw or my DeWALT drill/driver, and extra trips up/down the ladder.

Speedi-Grille Ceiling/Wall Register - Hands Free Installation!
Speedi-Grille Ceiling/Wall Register – Hands Free Installation!

The Speedi-Grill is permanently mounted with the included screws:

Speedi-Grille Air Register - Ceiling Mount
Speedi-Grille Air Register – Ceiling Mount

View of the completed Speedi-Boot and Speedi-Grille air vent installation in the basement ceiling. The air flow from the new vent can be felt in the middle of the room – nice! The basement should be a lot more conformable this winter.

Speedi-Boot and Speedi-Grill: Drywall Ceiling Mount
Speedi-Boot and Speedi-Grill: Drywall Ceiling Mount

Speedi-Boot’s unique telescoping arms and screw attachment option made it easy to locate the air vent in the suspended drywall ceiling, where a installing a raw vent boot would be a real challenge.

Hope this helps,

Bob Jackson

ductworkHVACSpeedi-Boot
Bob Jackson
Bob Jackson
Technology product manager by day and a prolific handyman in the evenings and over the weekends. Bob was the founder of the original Handyman How To website and that tradition continues on this site with excellent new handyman content into the future.
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