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Best way to insulate this pipe in uninsulated space?

newguy101 Member Posts: 22

I have a baseboard hot water heating system. The upstairs loop runs into the garage attic and then back the house. I took a look at the pipe running in the garage attic (unconditioned space) today, and it seems very poorly insulated to me.

The first picture shows the entire length of pipe in the unconditioned space. The second picture shows that the holes cut in the plywood were not filled with any expandable foam to stop air leaks into the house. The third picture shows that someone wrapped one of the joints in the insulation with some sort of insulated wrap, but then they stopped.

I am not an expert, but this does not look like a job well done. How can I improve this situation? I am assuming I should fill the holes around the pipe where it exits and re-enters the house with expandable foam insulation. I could also try to find some insulated wrap for the rest of the joints in the insulation.

Is there anything else I can do? Is there better insulation than what is currently on there? I would be happy to cut it off and put something else there, if there is something better?

Thanks for the help!!!


  • What part of the country do you live in, i.e. how cold does it get?
    Often wrong, never in doubt.
  • MikeL_2
    MikeL_2 Member Posts: 300
    Be careful when relying on pipe insulation to protect piping routed through unconditioned space..    
    JUGHNE Member Posts: 9,378
    You must be in a fairly warm climate that that pipe has not frozen already. (Also your attic insulation looks minimal, possibly putting heat into the attic to protect the pipe).

    IIWM, I would leave the pipe insulation alone, but remove the attic insulation below it.
    Then build a plywood box around it, as airtight as possible.
    About 12" high, then thick fiberglass insulation on top of the pipe, before you put the lid on it.
    This will let the heat come thru the sheetrock to protect the pipe.
    Airtight is the key word here. You can Foam in a can any gaps including the holes thru the wall.

    If you lived up here in northern Nebraska, I would cut a ceiling grill into the ceiling just below it. Maybe a 6 x 14 return air face.
    This will look like it was always there. Insuring your added box would be the same temp as your house.
    No amount of insulation will keep a pipe from freezing without the addition of heat. A power failure without the pump running for 24-48 hours will prove this.
    EBEBRATT-Ed Member Posts: 11,223
    Yes, we need to know your location to provide the correct advise
  • newguy101
    newguy101 Member Posts: 22
    I am in southeastern CT. What you are saying makes sense to me - basically this is a freeze hazard unless I bring it "inside" the heated building envelope.
    JUGHNE Member Posts: 9,378
    IMO, yes, possible freeze up.
    And considering how close the first 90 is to the roof rafter and being able to put only minimal insulation to protect that section, I would also go for the air grill from the room below.

    Just experience from ceilings falling down and repairs in attics
    that were tighter quarters than yours. :(