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  1. #1

    ducts in garage wall

    Hello,

    I bought a house last year and I have the classic, room that half hangs over the garage is cooler...so after investigating i have decided to take down the existing insulation and spray foam a bunch of the floor and half walls from the garage side.

    My question: i have 2 vertical bulkheads that each contain 2 5" round ducts and within this bulkhead, there is some pink insulation, but no vapour barrier and the temperature output from the basement when i test the duct to the room is very different. i want to know if it is worth while to have the bulkhead fron taken off, remove the pink insulation and after taping all the ducts up properly, having it all spray foamed at the same time?

    Note: another room (above the main floor, not garage) also uses one of these ducts and is always cooler so i assume this is where the problem lies.

    Any sugguestions would be appreciated.

    Thanks,
    Erik

  2. #2
    Join Date
    Jan 2011
    Posts
    92
    where are the bulkheads located? inside the garage against the wall to the house? or inside one of the first floor rooms? also, is there a noticeable difference in the strength of the airflow between your basement vent and the vent in the colder room.

    where are the vents located on the second floor?- floor or ceiling?

    and finally- does just the one system condition both up and down stairs?

  3. #3
    Thanks for the quick reply!!

    The bulkheads run from the ceiling of the basement (about 2 feet up in the garage above the concrete foundation) about 1/2 way within the wall that is part of the house (other side of the front hallway 2-piece bathroom) up to the ceiling of the garage (floor for the second floor is at the same height) the other half is a bulkhead protruding into the garage by about 3 inches.

    The airflow seems close, most temperature is way off, none of the other ducts has connections taped, so i assume there is that loss over the length of the duct (i have taped everything in sight in the basement pretty much so far to help it out). each cooler room has 1 supply vent under the window and 1 return vent on the opposite side of the room. each room is about 10' x 10'.

    and yes its just one air handler in the basement for the whole house. the other side of the house condition very very well and i have started adding some dampers to balance it all too.

    thanks,
    Erik

  4. #4
    Join Date
    Jan 2011
    Posts
    92
    ok i'm getting a visual. Yeah it really does seem like you are gaining a lot of heat somewhere in those supply duct runs. I wonder if they are insulated. I would open the bulkheads up from the garage side. I'm guessing the ducts are metal and not flex since your asking about taping them. Taping the joints helps to reduce air leakage, but doesnt stop the heat transfer thru the metal walls of the duct. See about insulating the suppy pipe with duct insulation. Try to cover the whole line and tape the insulation joints to form a vapor barrier around the duct. While youve got the bulkhead open, make sure that there is an insulated barrier between the basement and the inside of the bulkhead so the less conditioned basement air cannot enter the bulkhead. Lastly; you need to improve the insulation between the garrage and the inside of the bulkhead. It seems that this is where you are gaining a lot of heat since the back half of the chase boarders the inside of your living space. Filling the empty spaces inside the bulkhead with fluffy insulation isnt really necessary if you have insulated the duct.

    Also, I know you are improving your floor and wall insulation on the garage side, you might want to check out the insulation in the exterior walls bordering the other cool room as well as the attic insulation above said rooms.

  5. #5
    I cut a small hole in the bulkhead and it has some pink batt insulation, but no vapour barrier and alot of empty space within the void (probably why some of the wall in the bathroom is cold, but not all of it).

    Also, i know that where the duct exit the basement is leaking into the bulkhead, lots of room for improvement with some plastic tape and acustic sealant.

    Also, I think it will help, but lets see what you think...the other side of the house actually gets too warm in comparison to keep the problem side warm so i am trying to find a rectangular duct volume damper to try and balance it just after it comes off the furance to the too warm side.

    The attic insulation is my next project after i run all new cable, ethernet and stuff to the rooms. the house is only 9 years old, but i am going to top it way up once im done moving it all around for the install.

    Thanks again,
    Erik

  6. #6
    Join Date
    Jan 2011
    Posts
    92
    damper sounds like a good idea. You can always make one. Youll probably be able to cut one out of some stiff metal and find some hardware a lot easier than finding one that will fit.

  7. #7
    I managed to find a supplier in the area that makes them so i got lucky there. Also i did some temperature readings at another register and one in the cooler room. The average result is that the cooler room output is 11C less and as i said before, just slightly less flow.

    Does that sound enough off that my thought is correct of the garage cooling the duct sufficiently to cool off these rooms?

    Thanks again,
    Erik

  8. #8
    Join Date
    Jan 2011
    Posts
    92
    yes it definateley sounds like the duct is being exposed to some unconditioned areas thereby loosing/gaining heat. It seems like the garage is the only place it could be.

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