Cutting Floor Joists For Ductwork

To minimize problems with ductwork.

Cutting floor joists for ductwork.

Sometimes joists are notched at the end where they bear on a wall or sill. So in direct correlation to those cut joists are ou. Proper way to cut a joist and go to images. Use sheet metal duct elbows to work around bends and tin snips to cut the ductwork for a precise fit.

Leave backing on the tape on metal ductwork. If the cut outs are too large or in the wrong location the joist can be weakened and unable to support the load it was designed for. Attach ductwork that branches off and approaches each vent or register in the house. Here s bob s trick for taping a seam on a pipe that s installed close to the subfloor.

Hvac can run parallel to floor joists though and there are code acceptable ways to cut holes into joists but generally those holes are not big enough for hvac ducts only plumbing and electrical. Just be sure to get the sizing sorted out correctly ie a 12x12 duct cannot be replaced by a 3x48 duct same area as there s a lot more friction in the 3x48 but the correction factors for duct shape are surely. But without proper support ducts can develops sags or kinks that reduce airflow 4a 4b. Peel off part of the backing.

Cut a piece of foil tape to length. Tradespeople often need to cut notches or holes in floor and ceiling joists to run pipes ductwork or wires. I own an old home circa 1919. The hvac should have gone up a wall not laterally under a floor by cutting joists.

In the 70 s when the new furnace was installed they cut through the floor joists to run the air ducts. 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. If you need to cut through a joist firm up the floor as shown in fig. If the ducts are going to be concealed all seams need to be taped or caulked.

You may be able to work with a wide shallow duct so you can have a broad not too deep soffit for the cross joist duct run.