How To Install Flex Ductwork In Attic

Cut a piece of foil tape to length.

How to install flex ductwork in attic.

One of the most common mistakes when installing attic ductwork is choosing. Sometimes the best route for a flexible duct run is up and over an obstruction. Add a support joint and then place another piece of the ductwork onto this. Pull the webbing back toward the joist to form a loop.

The official recommendation from the adc is that flex ducts should sag no more than 1 2 per foot of length between supports. The first thing you want to do is take either air duct sealant or mastic and spread it around the take off. Your support joints must be at least 4 inches long and be beaded both sides. Here s bob s trick for taping a seam on a pipe that s installed close to the subfloor.

Secure all connections and seams air tight with heat resistant tape recommended by the duct manufacturer. 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. Give your ducts the proper support. Leave backing on the tape on metal ductwork.

Slide connectors inside the duct on each end. The straps that hold up the flex duct need to be no less than 1 5. Choose properly sized 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. Raise the webbing until the bottom of the flex duct sits 1 2 to 1 inch off the bottom of the attic. Another biggie that i see all the time is sagging ducts. Add extra insulation to ducts in areas such as attics where cold wind might blow in.

Peel off part of the backing. If the ducts are going to be concealed all seams need to be taped or caulked. Slide the webbing under the flex duct. Spread it around with either your fingers or a disposable chip brush or disposable paint brush.

How to properly install ductwork in an attic tip 1. Attach the joint into the middle and secure with more duct work. 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.