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Attic Insulation

Discussion in 'The DIY Room' started by ReelFaster, Oct 9, 2019.

  1. golf66

    golf66

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    Attic insulation is a tricky subject. Fiberglass batts can indeed have very high R ratings, however, they are utterly ineffective at sealing air leaks no matter how carefully you place them. Here is a picture of a whopping air leak in my attic....notice how the pink insulation has turned black which is because dust-laden air was moving through the insulation over the years. It was causing frost on the sheathing during the winter, a sure sign of heat loss. You will find air leaks around pipes, wires, sheetrock joints etc. They must be sealed up or they will render R60 batts useless. I shot spay foam on the attic deck to seal all the air leaks and then blew 16" of cellulose on top. The utility bills dropped like a rock.

    attic air leak.jpg
     
  2. papadave

    papadave

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    Prime example right there. I had the same issue in the stove room.
    It's fixed now.
     
  3. ReelFaster

    ReelFaster

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    Amen to that, I've got plenty of dirty fiberglass I've come across from doing some work up there.
     
  4. 343amc

    343amc

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    I had R19 in the attic when I bought this place last year. I had to remove most all the insulation when I rewired the house. I went though countless cans of foam to fill the air gaps as best I could, put the fiberglass back down (it was in decent shape, maybe 20 years old) then blew cellulose on top. It took about 3 hours to blow it in with my wife manning the machine and me in the attic. About 1200 square feet. I should be somewhere in the mid R40s if I did the math right.
     
  5. RabbleRouser

    RabbleRouser

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    You may not like my reply but. Over the past twenty years I've crawled through and inspected a couple thousand attics and seen everything you can imagine. If it were me, I'd bring in a contractor to do the whole thing in closed cell foam. It will be it's own vapor barrier, close every air leak and insulate better than anything else. It's clean, not attractive to rodents, you still have easy access for any future work or repairs... Really the only drawback is that you have to pay somebody else to do it, which I agree, really sucks, but the end product is 100x better. I literally do everything myself, just because nobody else would do it to my standards but in this case, I would just have a long talk with the contractor, a clear & concise contract and he doesn't get the final check till I'm happy.

    P.s. I'd burn my house down before I put blown in cellulose in my attic! I hate the stuff, vehemently! :headbang:
     
  6. ReelFaster

    ReelFaster

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    No double closed cell foam is superior to most insulating products however its $$$ and than paying someone on top of it $$$, I simply cannot afford it but if I could it would surely be the way to go :yes:

    I got up there this weekend into both attics, in the one attic which is covered with particle board flooring :headbang::headbang::headbang: (I truly detest that stuff) I air sealed as much as I could or should I say what was available to me as I pulled some of it up prior to run electrical, bath fans, etc... I also replaced some damaged fiberglass batts with some brand new. The other attic was in better shape and had more insulation that I originally thought as someone added more insulation to that side at some point. Again I air sealed the hec out of it as much as I could as it was much easier to do with no particle flooring down. I was able to track down some good air leaks by dirty fiberglass and did a decent job sealing many leaks up. I also again replaced a bunch of fiberglass batts that were heavily damaged prior by rodents and also by us working in there when we 1st bought the house. I also air sealed that attic's entrance hatch which is half way up the steps so I know hot hair is passing by that in the winter time and hopefully will not be leaking out.

    It's not the full blown job I originally intended on doing as I took a step back, looked at the overall scope of the job and the amount of $$ & time involved, talked it over with my wife and concluded we are not sure how much longer we will be in this house so I held back for now. Every little bit helps so hopefully what I did will help out a little.
     
  7. Canadian border VT

    Canadian border VT

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    I think you did right thing ReelFaster.. Is closed cell a great product YES!!
    But there are several issues with it, if it's not a applied properly and if it is you can still have a problem because your house can become too tight. And then you have to go back and add an HRV (5k minimum) for ventilation.
     
  8. woody5506

    woody5506

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    Cellulose and fiberglass both suck in their own ways. Mice seem to love fiberglass, but cellulose is miserable to clean up if you ever have to do ceiling repair/replacement like I had done at my old house. gutted the room and when the ceiling came down, I was standing in about 2 feet of cellulose covering the entire room.

    My house was so poorly insulated when we moved in a few years ago and I finally got the worst areas (attics) taken care of last year. I got to know a guy who had some work done at our shop who owns a small insulation company and figured I'd return the favor and hire him to get my attics up to par. He air sealed and blew in two large attics (split level home) with about 16-18" of cellulose. He charged me $750 per attic. The savings I would have had from doing it myself was minimal for how much I needed blown in. My gas bill has gone down drastically - last year I used half as much gas as the year before getting the insulation though I kept my thermostat set higher all winter.
     
  9. papadave

    papadave

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    So, ReelFaster , any updates on how this has helped/not helped?
     
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  10. ReelFaster

    ReelFaster

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    I was just thinking about this the other day. I said to myself I noticed the house being a little warmer/tighter BUT it hasn't been cold for very long. We've had some up and down days, 63 one day and 35 the next day or two. I'll get a better handle on it once we hit a nice stretch of colder weather.

    But just initially house felt warmer. I think the little air sealing I did above the bedrooms has helped but I truly think the air sealing in the attic above dine room and family room is making a nice difference. Sealing up the can lights, light fixtures, added/fixing some insulation, sealing up the attic hatch properly, etc...
     
  11. papadave

    papadave

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  12. schlot

    schlot

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    I've posted before (ions ago) about my house and my "lodge" and the issues with insulating them. I'm sure papadave remembers :)

    Both are older homes and I would recommend chasing air leaks down first before doing any insulation. The photo above showing the black batt insulation is a great example how it's a critical piece of the puzzle.

    I understand stepping back from a big project if you're not staying there a long time. Although the attic is the biggest bang for the buck if you do upgrade insulation, right after sealing off air leaks.

    I just sealed off a big air leak in my bedroom. My father in law did the work on the house we live in, before I married his daughter. The way he built a large display shelf allowed attic air to enter into the uninsulated bedroom wall. The gap was about 2" tall and ran the width of the bedroom. He used it as an electrical chase also so sealing it off with plywood was not possible.

    It was a nightmare sealing it off, but thank the man above for spray foam!
     
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  13. billb3

    billb3

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    +1 with air sealing
     
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  14. schlot

    schlot

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    Eons...lol, yes that would make more sense.

    Spelling is a second language for me. :)
     
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  15. yooperdave

    yooperdave

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    We had this house "re-insulated" this past summer. Added to walls, attic, rim joists and craw space. The crawl space is under a formerly front porch that was converted to living space about 30 years ago.

    Supposedly, everything was insulated; just not so well and we even found some stud cavities that had no insulation in them! Blown in cellulose for attic and walls. Joist ends and crawl space walls (from floor to ground level-just below grade) ended up with two different types of spray foam.

    The crawl space walls have a rigid tough spray foam (closed cell I believe) while the joist ends have a softer spray foam (open cell). In addition, the crawl space got a nice thick strong no seams vapor barrier on the ground. It is spray foamed to the walls (block) to satisfy the "sealed envelope".

    So far, the results are noticeable as I am burning less wood with the OWB but mostly noticeable by the frequency and duration of the blower motor run times.

    I will reserve final judgement for when the below zero temps show up. You know-those ones we're used to seeing? -30f to -40f? With winds?

    That'll be the real test!
     
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