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Air sealing satisfaction.

Post in 'The Green Room' started by TradEddie, Jan 23, 2013.

  1. RustyShackleford

    RustyShackleford Minister of Fire

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    Thanks for the suggestions, but I've already done the electrical rough-in (and I'm not gonna rip out my makeup to put in better boxes :) I thought of pigtailing the outlet boxes, so I'm not disturbing the cables coming into the boxes much when I install the fixtures - and it's considered good policy by some anyhow.

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  2. nate379

    nate379 Guest

    Good question. The boxes on teh outside wall of my house are fairly leaky. Wouldn't foam be bad... fire hazard?
  3. RustyShackleford

    RustyShackleford Minister of Fire

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    I asked about this is one of the electrical forums and they seemed to think not a problem, pointing out that when people insulate the wall stud cavities with spray foam, the outside of the box is pretty much buried in the stuff. Putting spray foam INSIDE the box is definitely a no-no, if for no other reason than it uses up volume in the box and the NEC makes a big deal about a box having enough room for the number of wires etc.

    My main concern about caulking, as I said, is that when installing the fixtures, all the stress on the wires may break the caulk loose.

    Called the local specialty electrical supply house and they have weatherproof boxes - supposedly a flange and rubber seal where the cables enter (perhaps the same as discussed above ?). They don't sound terribly expensive either, so I'm gonna go check 'em out, and maybe rip out my rough-in after all, at least on a few of the exterior-wall boxes where the only thing connected so far is the grounds.
  4. seige101

    seige101 Minister of Fire

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    Acoustic caulking remains flexible or a 100% pure silicone applied liberally should do the trick for you
  5. RustyShackleford

    RustyShackleford Minister of Fire

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    If you're responding to my concern, thanks - but, even a caulk that remains flexible could be a problem. Typically, when connecting fittings (or jamming all the wires back in the box when you're done), you'll end up pulling or pushing the Romex (usually pushing, I find). If the caulk plug breaks loose and decides to stick to the Romex instead of the box, you may end up with no air-sealing at the knockout, and a caulk plug attached to the Romex 1" before it enters the box. If the caulk stays attached to the box, you're probably golden.

    I've also read that silicon caulk can conceivably degrade certain plastics, so due to the safety concerns, I'm reluctance to apply it toRomex. I've also read that the non-acetic acid containing silicon, such as GE Silicon II caulk, does not contain acetic acid and probably doesn't have this issue. For the same reason, I intend to usee Silicon II around my glass IGUs.
  6. seige101

    seige101 Minister of Fire

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    Electrician is my day job ;) They also do make a fire rated touch and foam you can cover the knockouts/cables in. You could also try fire caulk if you have concerns about it reacting to the sheathing on the romex. There are several different kinds some get hard like concrete and others stay relatively soft. Never had a problem using 100% silicone with romex. (I like to caulk the wire where it goes outside the building for water proofing and air sealing)
  7. seige101

    seige101 Minister of Fire

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  8. RustyShackleford

    RustyShackleford Minister of Fire

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    Thanks for the link seige101. I don't think those are the boxes the place here had, because they said they actually have a rubber seal on the knockouts - the instructions for the ones you linked still specify caulking the knockouts. I'm gonna go look, and probably buy, some of these tomorrow - I'll report back.

    The caulking I've done thus far has been with the DAP Dynaflex 230, the same stuff I'm caulking my framing joints with. But I expect you're right that the concern with silicon causing problems is silly. I still intend to use Silicon II on my expensive IGUs though - it's only like a buck more per tube, and it doesn't stink as badly.
  9. RustyShackleford

    RustyShackleford Minister of Fire

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    Ok, got my boxes. The boxes have a lovely flange, about 1" wide, around the perimeter, with a spongy gasket for the drywall to compress against. And they mount using angled screws that are inside the box. They're big too, 22 and 42 cu-in for the 1- and 2-gang, respectively. Each box had a few holes, and then plastic pieces to seal the holes and/or allow wires to pass through. There was also a little stick-on rubber seal thingy that sticks to the box outside each hole. So the seal is far from perfect, but still a lot better than regular boxes. They are Arlington F101F and F102F, $2.24 and $7.41.

    http://www.aifittings.com/products/spec-sheets/VAPOR_BOXES.pdf
  10. EatenByLimestone

    EatenByLimestone Minister of Fire

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    That's awesome! You're saving 1200 bucks a year from your efforts!

    The last year my father heated this house and burnt 700 gallons of oil. I then inherited it and cut it down to 400 something by keeping it a bit cooler and doing some insulation work and windows. I then switched to gas as I saw the writing on the wall for oil. At that time the house was around 900 sq ft. I've since built out the attic and added 50% to the size of the house.

    I put the up the rest of the foam and half taped the final 15 feet of the front of the house today. I'll wait until the Great Stuff around the edges seals and then finish taping the rest of it. We had a dusting of snow last night and I could really see the difference on where the snow melted. All of the heat I was loosing on the front was pushed to those 15 feet. It really made that part of the roof look bad. By the end of today or early tomorrow any leaks on the front of the house will be from below the floor level. I'm a bit excited to see what happens when we get 2-4"of snow Monday or Tuesday.

    Matt
  11. TradEddie

    TradEddie Minister of Fire

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    I'd more realistically put it at about $400/yr, those early years had more heating demand for sure, e.g. 2005 my wife was at home with a baby for 3 months. The very odd thing about that chart is when I realized that in 2006 we finished 400sqft of basement, adding 20% to our heated area, but it had no adverse effect on out heating bill, possibly the opposite, I'm wondering if the incidental benefit of insulating almost half of the basement perimeter and more than half of the basement floor balanced out the increased heating space.
    We had a dusting of snow/ice yesterday and it was nice to see the obvious benefits on my roof where I'd fixed some problems just a few weeks ago. I used to have a huge clear spot in the middle of the roof from an open joist bay, now blocked.

    TE
  12. semipro

    semipro Minister of Fire

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    I also recently identified a trouble spot by inspecting the roof after a snow. (quite by accident actually).
    The problem turned out to be a lack of insulation in a cathedral ceiling where an interior wall met the roof.
  13. laynes69

    laynes69 Minister of Fire

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    It's amazing the amount of energy one can save by doing some detective work. We still have ways to go. At one time our home required 2- 150,000 btu oil furnaces, and after insulation and air sealing we have a heat loss of around 75,000 BTUs at 0 degrees. After this spring and summer, those numbers will hopefully be reduced.
    milleo likes this.
  14. EatenByLimestone

    EatenByLimestone Minister of Fire

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    I bet it did balance it out. You stopped the cold air coming in from ground level. I have plans to do that in the future, but other than new windows down there it isn't happening anytime soon. I've got to fix a water issue first. I'm going to hope and pray that gutters will solve it. If they prove successful then I'll insulate from the outside. If they don't I'll have to excavate down to the footer, put in a drain and then insulate all in one shot. I really don't want to do that. I'd rather have it dry then insulate the top 4 feet with a sheet of foam. I don't know what I'd cover it with though. Maybe a parge coat of some sort.

    Now I need to keep an eye on the south facing side of the house. There are 2 short sections of knee wall there. I don't remember them showing lots of leakage, but now that the front leaks have been plugged they might become the next largest issue.

    I wish I had an IR camera. It's going down to 14 tonight, it would really show where the heat is leaving the house.
  15. EatenByLimestone

    EatenByLimestone Minister of Fire

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    Great job! What kind of things are you working on now that you cut out so much leakage?

    Do those big oil burners short cycle now or are you totally on wood or pellets?

    Matt
  16. milleo

    milleo Feeling the Heat

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    Gonna be colder in southern maine tonight....What is going on here? Alaska warmer than Maine...Makes no sence to me!
  17. EatenByLimestone

    EatenByLimestone Minister of Fire

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    I had this happen. My problem was made worse by having a number of outlets, a hardwired CO/smoke detector and subpanel in the wall. I had to open up the wall, create a temporary floor across the hole by stuffing in paper towels into it, and then foam the heck out of it. The paper towels stopped the foam from falling down into the wall cavity. It pushed the leak over to the knee wall area so I had to seal that area also.

    Matt
  18. milleo

    milleo Feeling the Heat

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    Opps you no in Alaska or are you?
  19. EatenByLimestone

    EatenByLimestone Minister of Fire

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    I'm in Schenectady, NY. We're about 15 minutes west of Albany.

    Matt
  20. milleo

    milleo Feeling the Heat

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    Lol....It's still gonna be cold here tonight, especially for this time of year.
  21. laynes69

    laynes69 Minister of Fire

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    Well, it's a long story. Before my father bought this home from my grandparents, it was a wreck. Before it was insulated in '79, grandpa had the furnaces installed. His bill in the 70's got as high as 700 a month with the dual furnaces. He had the walls insulated with urea formaldehyde foam by my father in '79, which cut his bill in half. When dad bought the home, half the windows were shot (rotted or cracked), so the lower ones were replaced by vinyl double hung-double pane windows, then the upper windows in '93 (we have 42 on the house). Dad also had the attic insulated in '93, but paid no attention to airsealing. Over the next 10 years, it settled to only 3" of cellulose. He had concentrated on tearing out the walls with the deteriorating plaster and installing a vapor barrier and fiberglass. What he didn't concentrate on was airsealing.

    About 7 or 8 years ago, we bought the home. I had to install a full duct system to heat the upstairs, which had a 20 degree difference from downstairs. I've torn out a few rooms, and concentrated on airsealing with fiberglass batts, vapor barrier and drywall. The rooms I've done, even at 0 degrees are warm ( we have 8" walls). I've airsealed the attic, crawling on my hand and knees inspecting the entire attic from the middle to end, and sealing any voids or cracks. I cleaned out each crack to allow for either foam or caulking to penetrate the leak. I capped 32 open cavities (balloned framed home) in the attic, and I added 12" on top of the 3" that was there. I've installed foam gaskets, insulated and sealed all hidden ductwork, and went around the base of the exterior walls looking for openings or voids.

    Currently I need to tear off our old laundry room which is rotten and squirrels have been entering. It will eventually become a 2 story addition. In the winter, it feels like an airconditioner running with a box fan. Our den is half torn out, exposed lathe and plaster and the room above it needs gutted for a bathroom. I want to build an insulated door for the basement (extremely leaky), spray foam where the walls meet the foundation and tear out some of the already replaced walls where air sealing wasn't done. I also want to finish insulating the ductwork in the basement. We had an energy audit done, and while our home was very leaky (I can smell fresh air when it's windy), the neighbors new home down the road was leakier. Not bad for a mid 19th century Victorian. I've done a ton of work, and it's payed off greatly, but like I say there's plenty more.

    I forgot to add, we have a 90% efficient propane furnace that's about 25 years old with little use. Our old woodfurnace would use up to 10 cord or more and we would use half a tank (200 gallons of propane or more) a season. Since I airsealed, insulated the attic and replaced the woodfurnace with a EPA model, I've been able to heat 100% with wood. I've burned about 5.5 cords this year since September and the home averages 72-75 depending on weather. The 1200 sqft basement stays in the mid 60's while the 2 floors above remain in the 70's. IMG_0893.PNG
  22. EatenByLimestone

    EatenByLimestone Minister of Fire

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    That's impressive! I wonder how low you can get those bills?

    On Monday and Tuesday we had about 8" of wet snow. A few sunny 40 degree days later the side I finished working on has a full coat of snow except for a few little spots right at the bottom of the roof. Since the rafters have been sealed to the floor with foam I think the spots are from warm air moving up inside the exterior walls. There isn't much I can do about that now. I think my efforts are better spent on the South facing roof and then on the basement.

    Matt
    laynes69 likes this.
  23. semipro

    semipro Minister of Fire

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    Rusty, are you going for "airtight drywall" as an interior air barrier?
    http://www.finehomebuilding.com/how-to/departments/energy-smart-details/airtight-drywall.aspx

    Or, do you already have an external air barriers such as housewrap?

    I guess what I'm getting at is that its best to establish one really good air barrier somewhere whether exterior, in the wall, or interior.
    Trying to fix a leaky exterior air barrier by sealing inside isn't really going to help much. There are just too many places where the air can make its way in (baseboards areas, etc).
    Interior air barriers only work well when done during framing and wallboard installation because all connections between materials have to be sealed somehow.

    After chasing infiltration from the inside with outlet sealing etc. for years I realized that I was wasting my time. Once I started concentrating on the outer air barrier, one I could actually get to directly, I started making real improvements.
  24. RustyShackleford

    RustyShackleford Minister of Fire

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    Yes.

    I have that too. But of course it's not perfect, most notably at the top and bottom. I've also tried to make the external barrier better by caulking all the framing joints before the insulation was installed. And yes, I realize it's a really bad idea to have a vapor barrier on both the interior and the exterior. In fact, here the in hot humid southland, where it's frequently more hot and humid outside the house than inside, the usual wisdom of an indoor vapor barrier is explicitly counter-recommended by the building inspector's office. So I have neither.


    Exactly. I guess I failed to mention that this was new construction - a small addition on the rear of my house.

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