Down Flow Heaters

[CoolHandLuke]

Every time I build a 2 story I have to place a down flow heater for I cannot get heat and air to the portion of the home covered by the second story.

Of course this is more expensive for it requires an Heat and Air ground job.

Is there a way to design a 2 story without needing a down flow?

Thanks

[SH_Canada]

this is done all the time in canadaland. furnace in the basement. bulkheads sometimes, 5" ductwork in the joist cavities. cold air return in joist, interior wall cavity

 

[joey_martin]

2 words...

Floor

Truss

[joey_martin]

[DRAWZILLA]

i have been building the second floor up on a 4x8 block up on top of the existing c.j. , double block between the ceiling joists  I have been doing this for 40 years now. The framers love it b/c you create a duct space and room for large beams when needed. manother plus is new floor is not a part of the ceiling , so no sound transmission . The clients I work with want nothing to do with trusses of any kind. extra time is most of the reason. After the block up you have approx. 18" to work with

[SH_Canada]

4 hours ago, joey_martin said:

2 words...

Floor

Truss

just have to add another riser or two. I have not yet seen one at 11-7/8 tall.

 

but they are slick for mechanical, plumbing 

[robdyck]

8 hours ago, jasonN said:

I have not yet seen one at 11-7/8 tall.

You really need at least 16" depth in order to fit any main ducting (plenums, not branch lines) between the webs / chords. So 16 risers will just work (in Canada) with a 9' ceiling (109 1/8 + 16 3/4 = 125 7/8 / 16 = 7 7/8).

I used to work with a builder who insisted on using 14" floor trusses and there were always problems with fitting any ducting, except for where duct chases were built into the truss. Many truss suppliers will have a chart or diagram indicating the rectangle and round duct size that will fit base on the truss depth.

 

Keep in mind that if this type of structure is over an attached garage, you'll need at least that depth to get spray foam insulation under / around plumbing traps and under / around heat ducts.

And plumbers / hvac trades will need to install as high up as possible, and typical strongback bracing under the top chord may have to be designed to accommodate those mech. items as well.

[joey_martin]

Triforce has an 11-7/8" truss, but as @robdyck you really need the 16" if you are going to use these. They are great for my area to keep posts and bulkheads out of finished basements. 

 

https://www.openjoisttriforce.com/triforce-features-and-benefits/#joistsize

[SH_Canada]

4 hours ago, joey_martin said:

 

 

https://www.openjoisttriforce.com/triforce-features-and-benefits/#joistsize

it's even 22', field cutable to size. very nice product.

 

4 hours ago, robdyck said:

You really need at least 16" depth in order to fit any main ducting (plenums, not branch lines)

good to know

 

if only there were beams one could put ductwork through  all bulkheads could be eliminated