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Thread: insulation above workshop

  1. #1

    insulation above workshop

    Hey guys

    Got a 30x40 pole barn with metal sides that I've converted the back 20x30 part of it into a workshop. I've studded up and insulated the walls with R-19 and added sheetrock. I've now installed a drop ceiling grid with 12 led troffer lights. I'm to the point of wanting to insulate the ceiling and add the tiles . I'm trying to decide if I need to spend the extra money for R-38 here in the Nashville area or if I can get by with R-30 which is quite a bit cheaper.

    I'll be heating and cooling the space with an 18k btu Pioneer minisplit heat pump.

    Thanks!

  2. #2
    I would think that if the cost difference is 15% or less for the total amount of insulation, that the pay back would be pretty quick in your area, particularly if you air condition the space.

    annual heat loss = 24*HDD*Area/R-value
    annual heat gain = 24*CDD*Area/R-value

    You can get your annual heating degree days (HDD) or cooling degree dfrom NOAA for your area. You do this calculation four times, twice for each R value for HDD and CDD
    Last edited by Lee Schierer; 03-23-2020 at 4:40 PM.
    Lee Schierer
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  3. #3
    Quote Originally Posted by Lee Schierer View Post
    I would think that if the cost difference is 15% or less for the total amount of insulation, that the pay back would be pretty quick in your area, particularly if you air condition the space.

    annual heat loss = 24*HDD*Area/R-value
    annual heat gain = 24*CDD*Area/R-value

    You can get your annual heating degree days (HDD) or cooling degree dfrom NOAA for your area. You do this calculation four times, twice for each R value for HDD and CDD

    Do keep in mind that the payback period may be longer if the shop isn't occupied all the time. That is, if it's at 50F 4 days a week because you're not out there, the amount of insulation isn't as big of a deal as it would be if you're out there morning to night 6 days a week.
    Licensed Professional Engineer,
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  4. #4
    How large are the tiles ? Is there a vapor barrier ? Is the insulations weight an issue ? Drop ceilings seem to rare in pole barns . I'd go with all that I could , when it comes to insulation . Also , what's your location ?

  5. #5
    Join Date
    Apr 2013
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    Words I have never heard — “I have too much insulation in my attic.” The Department of Energy recommends R38 as the minimum for residential attics in almost all of TN and you will never second guess your decision. If you are buying at Lowe’s or Home Depot you can pick up a 15 percent off coupon on EBay.

  6. #6
    Quote Originally Posted by james manutes View Post
    How large are the tiles ? Is there a vapor barrier ? Is the insulations weight an issue ? Drop ceilings seem to rare in pole barns . I'd go with all that I could , when it comes to insulation . Also , what's your location ?

    I went with a drop ceiling as it's low weight and my trusses are 5' on center and not designed for significant load carrying. I'm near Nashville.

  7. #7
    True on the more is always better. I wont' be in the shop all the time as it's not my full time job. But I dont' want my heat pump running all the time either because I have bad heat loss. Just trying to create a humidity controlled space where my tools don't rust as bad and I can work comfortably year round.

  8. #8
    The thing about insulation is, you buy it once, and then it saves you money over and over every month.

  9. #9
    I'm assuming your ceiling tiles are 2' x 4' . Also assuming you are blowing in the insulation . If weight is not an issue , and the tiles are strong enough , seems like a no-brainer . The extra R- value pays you back every month . The difference in up front cost shouldn't be bad . Another point , Mini Splits throttle back as needed , as the room reaches your target . I set mine at the start of the summer -then don't touch it till fall . Set it for heat - then leave it alone . It will control the humidity better that way . On/Off , On/Off , not the best approach .

  10. #10
    Join Date
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    Like james, my mini split is pretty much "set and forget" and it barely blips our power bill as my shop is well insulated and has a ceiling made from drop ceiling tiles. (no actual drop ceiling due to headroom)
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #11
    Join Date
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    38 is about 25% more then 30. So if the r38 is less then 25% more in cost it is a good deal I suppose.
    Bil lD

  12. #12
    The installer will blow it in to a "depth" , and give you the R - value you will get from that depth . You will pay for his coming out and his time whatever "depth" he fills it to . My bids I was given showed increases for the material , labor didn't increase at the same rate . So , the deeper you go , it was less $-per inch . Not all folk's will be that fair , I realize . I found a good one .

  13. #13
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    I've not seen blown-in over a drop ceiling...and I worked in the business for a few years a few decades ago. Always batts over drop ceiling because folks tend to access via the tiles. Blown-in WILL find every possible way to infiltrate down into the conditioned space and dropped ceilings are not sealed like drywall, etc., is. I'm very much in favor of blown in and it's been used in portions of our home that are amenable to it, but I'd not use it for this particular application.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  14. #14
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    By drop ceiling, I assume the OP is referring to a t-bar & tile ceiling. If so, it's a very poor place to put insulation; just about impossible to get the batts fitting tightly & it leaks so much air that the insulation isn't going to be able to do its job.

  15. #15
    Frank's got a great point on air infiltration. If the space isn't reasonably tight, the insulation R rating may be a moot point. Blown in insulation can do a good job when dense packed, but I doubt you can get that with drop in tiles.

    Fine Homebuilding has done some good articles on insulating and they have a similar forum. Maybe post your question there?

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