How To Install Flex Duct In Attic

The first thing you want to do is take either air duct sealant or mastic and spread it around the take off.

How to install flex duct in attic.

In this video i use mastic and air duct sealant t. Pull both sides of your ductwork so that the insulation is free of the ends and then wrap duct tape around both pieces. Continue throughout the line until air can be discharged at the exit. Sometimes the best route for a flexible duct run is up and over an obstruction.

Raise the webbing until the bottom of the flex duct sits 1 2 to 1 inch off the bottom of the attic. I ll show you how to get the job done right. The official recommendation from the adc is that flex ducts should sag no more than 1 2 per foot of length between supports. But without proper support ducts can develops sags or kinks that reduce airflow 4a 4b.

The supports need to be at the manufacturer s recommended spacing but no longer than 4 maximum. Another biggie that i see all the time is sagging ducts. Isley s home service inc. Slide the webbing under the flex duct.

Installing flexible or insulated duct is an easy diy project. Pull down the insulation so that it covers the core. Mastic comes in a bucket air duct sealant comes in a tube they re basically the same thing. Attach the joint into the middle and secure with more duct work.

The straps that hold up the flex duct need to be no less than 1 5. Spread it around with either your fingers or a disposable chip brush or disposable paint brush.