Ventilation Ducts inside Wood Trusses

Originally Posted By: SE Texas
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Hello,


I am building my own house in SE Texas and wanted to
ask for anyones concerns about the HVAC Ducts I am
installing:

House is a two-story on a slab. I am having my home
insulated with icynene so it will have a very strong
moisture barrier.

The 1st floorceiling/2nd floor is18 open wood trusses.
The airhandler will be on the first floor - floor and
the ducts will be distributed thru the open wood
trusses.

The ducts will be made out of 1.5" ductboard on 3 sides
and use the plywood floor for the 4th side. None of
the 4 sides will be next to an UNconditioned space.

Is this OK?

If not, why & what solution do you recommend?


Originally Posted By: David Suelflow
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I?m not a big fan of ductboard. While it does lessen the sound transmission, I don?t like the insulation on the inside of the duct. There is too much collection of dirt and the possibility of mold growth. I prefer metal ducts with insulation on the outside.


Originally Posted By: SE Texas
This post was automatically imported from our archived forum.



Are there any negatives with the air coming in contact with the plywood or 2x4’s in the wood trusses?


Originally Posted By: cbottger
This post was automatically imported from our archived forum.



S.E. Tx


A/C units do not remove all of the humidity from the air. I base my thoughts on forty years in this business and do not recommend that supply air have any contact with wood what so ever as you basically have 55 degree air with a level of humidity that can and does affect wood over time. I have used wood chases on the return side but never on the supply side and that is my opinion for what it is worth.


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Don't argue with an idiot someone watching may not be able to tell the difference.