Scissor Joist Area for back.

[motrctyman]

I have an odd question.

Most of the houses I work on have media rooms on the second floor and are supported by scissor joists. I hope I am calling them the right thing as they are pre-engineered joists made out of 2x4's spaced 16" apart and use small lengths mitered 45deg as spacers.

My question is, could these be used as a separation for an IB? If there was 150 cu/ft of this air space in the floor that was open on the perimeter to an attic (on both sides), would this suffice? There is a lot going on in this area between ceiling/floor but inherently it is empty air space. Including the adjoining attics it would equate to about 1500 cu/ft.

It might make for an enteresting outtie or possiby a cabinet mounted securly to the floor as a reverse manifold?

[ThomasW]

The space is inherently too small, and with only 16" of depth there would be issues with the rearwave bouncing forward and interferring with the operation of the drivers.

One builder did mount multiple drivers in an engineered truss sustem. But his trusses were 24" deep and he mounted the drivers in individual truss bays.

[carpenter]

Hey motrctyman, how deep are your floor trusses? If you can't see, can you drill a small 1/8" pilot hole and probe with a wire? If that floor cavity is spanning the entire floor, and the floor is large, you have quite a bit of air-space, especially if it vents behind walls that open into the attic.

I think you've got an interesting idea developing...

I'm developing a second-story in room line-array that vents into the garage. Similar concept as yours.


btw, in case you're curious, a scissor truss is located overhead, in a vaulted ceiling, and resembles the cutting edges of a pair of scissors held wide open. What you have in your application are open-web floor trusses.

John Inlow