Best Way to Extend Duct into New Mudroom Addition


  #1  
Old 07-14-17, 12:39 PM
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Best Way to Extend Duct into New Mudroom Addition

I need to extend an existing duct/register from an adjacent room into a new mudroom, which will require cutting through the bandboard. On the other side of the bandboard, there is only about 5" of height between a concrete slab (yet to be poured) and the subfloor above. The existing duct is 6" in diameter. Is the best approach to adapt the 6" round duct to a rectangular duct, pass through the bandboard and over and up to the new register using a rectangular elbow, or is 5" not enough to do so? Since the slab has not yet been poured, I have the option to run a pipe under the slab, but this doesn't sound like the better option, to me at least. Thoughts?
 
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Old 07-14-17, 12:54 PM
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This is what I'm working with...

Name:  RegisterLocation.jpg
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Old 07-14-17, 12:57 PM
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I should mention that the horizontal distance from the existing register to the new register is about 8 feet.
 
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Old 07-14-17, 01:11 PM
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A little more detail...

Attachment 83053
 
  #5  
Old 07-14-17, 04:17 PM
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m,
A 6" round gives you 85 cfm's. You could use a 8 x 4 rectangle or what we call wall stack which is actually 8 x 31/4" to fit between studs in walls which would give you 90 cfm's.

Get a round to rectangle adaptor and run in like a regular branch to the new register. You could also use oval pipe the same way with the adaptors.

Hope this helps a little.
 
  #6  
Old 07-14-17, 08:55 PM
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Do they make register boxes and elbows that can fit in such a shallow cavity?
 
  #7  
Old 07-15-17, 06:47 AM
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m,

Home | Snappy Co.

Ductwork Supply | Duct parts | HVAC Parts and Supplies

This should give you some idea of what is available.

Hope this helps a little.
 
 

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