Open-cell foam or cellulose over ceiling?
The ceiling has been dropped 1 foot, and sheet rocked, as well as painted-
1 prime and 2 finish coats.
Tek track lighting and a few cans (IC) have also been installed.
The duct work is in and installed within the 1 foot dropped ceiling.
My question is:
Is it ok to use open cell soy foam directly over the duct work, and over
sheet rock directly? My carpenter is concerned for the expansion of the foam
over the sheet rock, itself, as well as spraying directly on the installed duck work.
I would save money and be able to use blown in cellulose to a depth
of rough;y 15″.
Please advise on our best course of action.
(we would box-in the cans before spraying)
thank you in advance
gs
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Replies
Where is this?
What is above the 1' drop?
Heat and or AC , Which dominates?
I have sprayed ducts with water blown open cell Icynene. I do not like the soy foams since reading that they have been more difficult for some to work with. My projects have been in new construction not homes that are lived in at the time. Never had a lingering odor once lived in like some have.
You can spray drywall.
As to cellulose most here prefer it as the most green priduct. Ducts that are buried in insulation may sweat and wet insulation if used for AC. Others say not a problem. There is a question about this here if you can find it with search.
Best bet, do the can covers, use standard duct insulation, then bury all in cellulose.
Gary,
It's unclear where your air barrier is. Is the new drywall ceiling your air barrier?
Like AJ, I'm curious to know what you have above the 1-foot drop.
we're in Norfolk, Ct, 06058
the work will be performed by a seasoned professional,
who has closed cell foamed all the vertical walls,
to a depth of 6 inches. did a great job-
we have installed radiant heat in finished
concrete floors, so the duct work is for AC only.
(we have heat ventilation recovery system, too)
thank you
the new dry wall ceiling is our new air barrier.
just above the dropped ceiling, and air barrier sits the duct work and cans.
the attic is unconditioned space, with ridge, sofit, and gable vents, under a brand new
standing metal seam roof- with NO holes in it.
Gary, I would let your guy do what he wants to do since he is there and you are happy so far. We are not there. Spray foam done right will work.
If your old ceiling was an air barrier, I would advise installing cellulose insulation in the attic, so that you disentangle (separate) your insulation layer from your mechanicals (ductwork and recessed cans).
However, if the new ceiling is your air barrier, my preferred method won't necessarily work. It all depends on whether the walls at the perimeter of the building (between the new ceiling and the old) are sealed against air leakage, and whether the old ceiling is airtight or leaky.
we took down the old ceiling, and dropped the new one.
we used metal studs for the new ceiling We also built a new interior
2X6 wall just inside the old wall cavity. this outer cavity was filled with closed cell soy foam sprayed,
and all wiring and plumbing is inside conditioned space. The sheet rock covering the wall cavities
and insulated closed cell space is air tight to the finished concrete floors and ceiling
Properly installed drywall will be fine. Closed cell 2", then cellulose would be bullet proof.
Gary, this is just too complicated an assembly for us to give you an accurate answer. You can see it so you understand all the components; it's pretty hard to visualize exactly what you have. Are the walls connected to the ceiling space? How airtight is the ceiling plane?
I would disagree with AJ that 2" of closed cell in a roof or ceiling is a good idea with 15" of cellulose below it and a metal roof above it. I'm usually an advocate of hybrid insulation systems but red flags are going up on this one.
Michael, he says the new drop ceiling is airtight to wall. Then sprayfoam backside of new airtight ceiling. Then ABOVE AND ON the sprayfoam goes the cellulose.
What you state none of us like, true. Lower the red flags my man and raise the green.