Plan the duct layout based on the HVAC system design and building layout
Measure all runs, branches, and fittings before cutting materials
Select the correct duct type, size, insulation, and fittings
Turn off power to the HVAC equipment before starting work
Install the main supply and return trunks first
Cut duct sections to length with proper tools
Assemble ducts using approved connectors, screws, and sealing methods
Seal all joints, seams, and connections with mastic or approved foil tape
Support ducts with hangers or straps at proper intervals
Keep ducts straight and avoid unnecessary bends or kinks
Install branch ducts to each supply and return register location
Connect ducts to registers, grilles, and diffusers securely
Insulate ducts in unconditioned spaces as required
Check for proper clearance from electrical wiring, plumbing, and framing
Verify airflow direction and damper placement
Test the system for leaks and air balance
Inspect all connections and secure loose sections
Restore power and confirm proper HVAC operation