How To Install Flex Ductwork In Attic

Raise the webbing until the bottom of the flex duct sits 1 2 to 1 inch off the bottom of the attic.

How to install flex ductwork in attic.

But without proper support ducts can develops sags or kinks that reduce airflow 4a 4b. Attach the joint into the middle and secure with more duct work. The official recommendation from the adc is that flex ducts should sag no more than 1 2 per foot of length between supports. Slide the webbing under the flex duct.

Sometimes the best route for a flexible duct run is up and over an obstruction. If the ducts are going to be concealed all seams need to be taped or caulked. Mastic comes in a bucket air duct sealant comes in a tube they re basically the same thing. Leave backing on the tape on metal ductwork.

Choose properly sized ducts. Secure all connections and seams air tight with heat resistant tape recommended by the duct manufacturer. Cut a piece of foil tape to length. Use metal connectors to join duct sections.

This is an especially relevant tip for flex ducts more on that in a. The first thing you want to do is take either air duct sealant or mastic and spread it around the take off. Here s bob s trick for taping a seam on a pipe that s installed close to the subfloor. Add a support joint and then place another piece of the ductwork onto this.

To prevent problems use saddles or straps to support at regular intervals 4c 4d follow the manufacturer s instructions but in case they get lost here is a list of best practices for. Slide connectors inside the duct on each end. Add extra insulation to ducts in areas such as attics where cold wind might blow in. Pull the webbing back toward the joist to form a loop.

Pull both sides of your ductwork so that the insulation is free of the ends and then wrap duct tape around both pieces. Another biggie that i see all the time is sagging ducts. How to properly install ductwork in an attic tip 1. The straps that hold up the flex duct need to be no less than 1 5.

One of the most common mistakes when installing attic ductwork is choosing. Your support joints must be at least 4 inches long and be beaded both sides. Slide the backing up and over the pipe. The supports need to be at the manufacturer s recommended spacing but no longer than 4 maximum.