How To Install Flex Ductwork In Attic

If the ducts are going to be concealed all seams need to be taped or caulked.

How to install flex ductwork in attic.

Add a support joint and then place another piece of the ductwork onto this. Use metal connectors to join duct sections. Mastic comes in a bucket air duct sealant comes in a tube they re basically the same thing. Secure all connections and seams air tight with heat resistant tape recommended by the duct manufacturer.

Slide the backing up and over the pipe. 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. Peel off part of the backing. Cut a piece of foil tape to length.

Spread it around with either your fingers or a disposable chip brush or disposable paint brush. The supports need to be at the manufacturer s recommended spacing but no longer than 4 maximum. Slide connectors inside the duct on each end. How to properly install ductwork in an attic tip 1.

Leave backing on the tape on metal ductwork. The first thing you want to do is take either air duct sealant or mastic and spread it around the take off. One of the most common mistakes when installing attic ductwork is choosing. Another biggie that i see all the time is sagging ducts.

Pull both sides of your ductwork so that the insulation is free of the ends and then wrap duct tape around both pieces. This is an especially relevant tip for flex ducts more on that in a. The official recommendation from the adc is that flex ducts should sag no more than 1 2 per foot of length between supports. Your support joints must be at least 4 inches long and be beaded both sides.

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

Here s bob s trick for taping a seam on a pipe that s installed close to the subfloor. But without proper support ducts can develops sags or kinks that reduce airflow 4a 4b. Choose properly sized ducts. The straps that hold up the flex duct need to be no less than 1 5.