Friday, March 9, 2012

Another Post About Soffits

Hurray!!! Soffits!!! or Bulkheads as I've learned they are called in some parts of the country.

Spent some time ripping down the old framing for the incorrectly done soffits.

This is the soffit for the exhaust pipe for the existing central heater.

Now you see it.


Now you don't


With the soffit gone you see the chase better.
This was where a chimney was and this chase goes alllllll the way up to the attic.

I'll spare everybody from all the before and after pics from the other soffits I removed, which look pretty much like whats above.

Fire Rated Chase Idea

I think that what I show above is the correct way to build a fire rated chase.
The drawing above is actually to scale.
Check out all those arrows!!! I luvs me some arrows.....

Additional Chase Questions
  1. Whats a reasonable clearance between the HVAC trunk lines and the top/sides of the chase and to each other?
  2. How much space should I leave below the trunk lines to run utilities?
  3. What's the best way to run the utilities given the construction method of the soffit?
  4. Does such a thing exist as a ceiling hung cable-piping tray? Is it code correct for me to run the utilities as shown?

Ducting Conundrum

Take a look at the diagram below.

The green boxes are the HVAC chases that I can make easily.
The problem is the right side of the plan.
That big red line represents where the old house ends and the addition begins.
I need to get two 7by8" HVAC trunk lines across that line.

Check out this pic of the area.
To the left I have a solid 4by12 under a 2by10 joist that I can not screw with.
Then, this entire wall will have to be sheared...
I'm stuck I can't see how to get the lines where they need to go.

Anybody got any ideas?

5 comments:

Jim said...

http://www.monosystems.com/ makes center hung cable trays; they might have invented them. My Uncle used to rep them and had t-shirts that said "I'm center hung." Classy.

The MadScientist said...

Thanks I'll check it out.
I didn't even know what search terms to use.
I kept getting results for managing computer cables on your desk.
Do you know if what I am proposing is even code approved?

Jim said...

No idea if it is to code. The last soffit I saw was in a house built in 1979. I've always seen the 110v run on top of 2x2s on the bottom side of the soffit, so I would think attaching it to aluminum would be even better if you tie secure the wires every few feet and earth ground the cable tray. You are suspending the wires quite a ways from any surface which in my mind is better than running the cables on the bottom where a nail could get at them. Ask your friendly local inspector, though.

Joel said...

Can you pick a spot in the shear wall where you want the penetration to occur, cut a hole in it, and then double up the hole? Looks like you have a few more things coming through the wall there. You can have a common point for all the stuff transitioning between the old house and the addition.

Joel said...

Here's another wild idea--if this is just for the basement unit, do you have to run the trunk line through the ceiling? Can you run it along the floor? Or can you arrange it vertically and run it between two joists in the wall and put an "attractive" bump-out on the wall?