Uninsulated Attic

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New Member
Oct 5, 2022
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Topeka ks
Friends, I live in a 1926 Craftsman style home in Kansas. 90% of the attic is completely floored. The attic is unfinished and has virtually no insulation and so I want to blow in cellulose. Before I do, however, I need A LOT of advice on prepping the attic.
  • I'll clean the empty boxes and trash out first!
  • Previous owners placed old carpet on the attic floor. Some of this old carpet is from the early 60s and so is probably wool. The underlayment was laid out on the attic floor too. Does that old carpet need to be removed or can I cover it with the blown-in insulation?
  • There are a few electrical junction boxes flush with the floor (pictured). Is it okay to cover them with insulation?
  • There are quite a few modern junction boxes. Some are affixed to rafters but only a few inches above the floor and some are on top of the flooring (pictured). Is it okay to cover those junction boxes with cellulose?
  • I need to replace several of the insulated ducts that have deteriorated over time. See photo.
  • There is a AC only unit in the attic. The supply plenum (pictured) is uninsulated. I know I need to seal the joints with mastic or foil tape and that I need to seal the register boxes. I assume that the supply box should also be insulated with something like R-8 Insulated Duct Wrap. Is that correct?
  • Should the return plenum be insulated? What about where the box containing the blower and coil?
  • The soffits are not vented. Should I still use rafter baffles?
  • I plan to use blown-in cellulose but I'm concerned about the box containing the blower and the coil. Any suggestions on how to keep the cellulose close but not in direct contact with it? I thought about using fiberglass batting and building a wall around the box to keep the cellulose out of it. Any thoughts?
  • The AC unit return plenum is smackdab in the middle of the attic and I need to be able to get to it to change the filter every month or so. Would it make sense to use lengths of rigid foam insulation to create a path to it?
  • The HVAC unit is AC only and there is one return vent in the hallway for the whole attic. I thought about cutting out a piece of rigid foam insulation board to cover the vent during the winter to cut down on heat loss through that hole in the ceiling. Does that make sense


  • Deteriorated Insulated Ducts.jpg
    Deteriorated Insulated Ducts.jpg
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  • Electricl boxes attached to rafters.jpg
    Electricl boxes attached to rafters.jpg
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  • In floor junction Box.jpg
    In floor junction Box.jpg
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  • Photo Oct 05 2022, 3 40 26 PM.jpg
    Photo Oct 05 2022, 3 40 26 PM.jpg
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  • Photo Oct 05 2022, 3 40 31 PM.jpg
    Photo Oct 05 2022, 3 40 31 PM.jpg
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  • Photo Oct 05 2022, 3 40 33 PM.jpg
    Photo Oct 05 2022, 3 40 33 PM.jpg
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