How To Run Ductwork Through Floor Joists

Is that a towel in there.

How to run ductwork through floor joists.

Ducts should be able to run between studs in the wall and then turn into a joist bay the space between two joists. 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. If you need to cut through a joist firm up the floor as shown in fig. What the installer did here was to screw a piece of sheet metal to the bottom of the joists and attach a duct to it to carry the air back to the hvac system.

As you can see the duct runs perpendicular and below the joist with one or two trusses thrown in. This size fits just between most floor joists. To minimize problems with ductwork. Position bathroom vent fans so the ducts can run parallel to the joists right up to where they exit the house.

I d look at splitting the duct into two 3 pipes as it passes through the joist. Attics can be problematic when insulation is located in the attic floor rather than in the rafter bays or better yet outside the roof sheathing. Isherwood jan 23 19 at 14 40 i m confused about what i m seeing up there. Most installers report they can get to a 100 sq.

Area through this access hole. Here are dome photos of the situation. Make sure the studs and bays line up well enough to leave a clear path. As we look closer here s what we see in this house.

The most common size duct used is 14 in. Add a false return grille cut an access hole in the ceiling of the first floor in a central area to gain access to the ducts. 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. This is typically the case for ducts that run through a dropped ceiling or soffit or between joists so long as the floor system sits on top of a conditioned basement or crawlspace.

Here are several ways to access ducts. I used a 6 hole saw to run a new duct into an addition we built. In this case it s big enough that there s even a joist running right through the middle.