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Rim Joist Insulation

Post in 'DIY and General non-hearth advice' started by Dana B, Oct 15, 2013.

  1. Dana B

    Dana B Feeling the Heat

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    I have an unheated, open basement in which the rim joists are not insulated. I want to insulate them but wasn't sure what the best way to do it is. At first I thought I'd use the spray foam and do it myself but the materials are expensive and I've read that you need a respirator an dmachine and the whole nine yards.

    Now I'm thinking it might be better to use the rigid board. I understand you still have to foam it in place. has anyone done this? Would you use a can of great stuff for something like this? I was thinking that (2) two inch pieces of rigid foam should get me to roughly R14 which from what I heard is reccomended for rim joist insulation in most areas.

    Any thoughts?

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  2. velvetfoot

    velvetfoot Minister of Fire

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    I did that. I cut the foam into blocks and banged them in there and caulked them in there. I'd recommend using the great stuff only with an applicator gun because you can't just start and stop another day with the can. Better yet, get a quote for a guy to come in and spray the foam in there.
  3. Dana B

    Dana B Feeling the Heat

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    I don't want to pay labor costs if I can do it myself with the rigid and get roughly the same performance while saving some money.

    I called aroud and the price on the 2 inch rigid foam boards (4x8 sheets) was all over the place.

    One company said 1.08 and another said 38.64 and some were in between. What's with the huge price difference?
  4. Joful

    Joful Minister of Fire

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    Sprayed foam provides a zero draft and vapor barrier, along with superior insulation. Foam board can be cut to fit, but eliminating all draft is a difficult challenge. It might be worth getting a quote or two on spray foam for the rim, before ruling it out.

    I have a spray foam job scheduled for next week, at my place. $1264 to do a wall adjoining attic space, which is almost entirely inaccessible. My choices for insulating this existing wall were either spray foam, or tear out the drywall to hang bats, and then replace the drywall. I went with the spray foam.
    Last edited by a moderator: Oct 19, 2013
  5. velvetfoot

    velvetfoot Minister of Fire

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    I got the foam boards at HD. 38 sounds more like it. Depending on how deep you make it, you could estimate how much you'll need.
    I wouldn't recommend my pounding it in and caulking method if you go that way. Get a dispenser for the great stuff and cut them small.
  6. Dana B

    Dana B Feeling the Heat

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    $1300 is a lot of money. IEverything I've read says that if you take the time to do it correctly you can achieve just as good performance with the rigid board and the can foam. If it cost $1300 to have it done w/ spray foam by a company compared to 300-400 to do it myself with the rigid and I actually getting my 900 -1000 worth by spending more money?
  7. velvetfoot

    velvetfoot Minister of Fire

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    You should see what it might cost as far as materials go, maybe it'll be more than you think, or not.
  8. Joful

    Joful Minister of Fire

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    I did. The materials were over $700 for DIY spray foam, for the amount of area I needed to cover. In my case (unique situation), with the space being almost impossible to access, I knew the job would come out less than splendidly, if I tried to DIY it.

    Back to the OP... your choice. Just throwing out another option you may want to consider. DIY is not free, when you figure in material, and what other thing you could've been doing with your time spent. I DIY most stuff (re-taping drywall, pulling wiring, putting up baseboard and chair rail with my evenings this week), but some stuff I contract out (HVAC install, spray foam, wall-to-wall carpet, etc.). It all comes down to your time / money balance, and everyone has a different tipping point.
    Swedishchef likes this.
  9. Dana B

    Dana B Feeling the Heat

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    Good points. I think I will call a few contractors just to get pricing on it and see what they say.
  10. velvetfoot

    velvetfoot Minister of Fire

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    I meant Dana should check the cost of the foam boards.
  11. Dana B

    Dana B Feeling the Heat

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    I have called a bunch of places and they do some to be kind of expensive. I'm waiting to hear back from the spray foam contractors.
  12. velvetfoot

    velvetfoot Minister of Fire

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    I meant figuring out how many pieces you had to cut out, for whatever thickness you wanted, and then figuring in the waste too, and calculating the number of boards you need, and multiplying by the price per board.
  13. billb3

    billb3 Minister of Fire

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    Likely the difference between EPS, XPS. ISO and then some are foil-faced.
    Animals might not chew through the foil and then again they might- the foil is supposed to also have some extra weathering protection.
    I did my sister's rim joints with foil faced XPS from Home Depot and put foil on the cut surfaces for the first few rim joint bays and then decided that was too much work and just cut the panels a little under size and foamed them in and got it done and over with. Her rim joints were so poorly made there were places I could stick my fingers outside easily. Her basement ceilings were mice and chipmunk hotels.
  14. Swedishchef

    Swedishchef Minister of Fire

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    +1 on spray foam.

    When I built my house, i had calculated the cost to put 2 inches of XPS on my basement walls. The pannels are 2X8. I would have needed to ensure the surfance was smooth, purchase anchors, SEVERAL tubes of PL300 (to ensure the board sticks to the wall preventing air from getting between the foam and wall), tuck tape, etc. I was going to cut out smaller foam blocks and goodstuff around them. I did the math: it would have cost me $2200 in materials. I figure it would have taken me over 20 hours (my house perimeter is 166 linear feet). I called a spray foam company and they quoted me $3400 taxed inc. SOLD.

    They came and taped everything up. They sprayed 1.5 inches of high density foam everywhere and were completely DONE in 2.5 hours. They charged me $2.25/ sq ft. They calculated the rim joists to be about 1 sq ft. So to do only the rim joists would have cost me about $380. And it is VERY air tight. When I open my basement entrance door, I feel the vaccum it creates.

    In my view some things are just worth paying others to do if the price is right. It's like an oil change: $40 at the garage and it's done in 15 minutes or: $25 for a gallon of oil and $10 for the filter + 1 hour of me cursing and trying to get under my car to get it done....

    Andrew
    Last edited: Oct 15, 2013
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  15. semipro

    semipro Minister of Fire

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    OP,
    I have done what you've described in my basement.
    I also put together a spreadsheet with foam prices based on volume (not R value), materials only.
    Contractor installed foam was the most expensive.
    DIY spray foam was next, but way more than DIY foam boards and not that much less than the contractor option.
    DIY using foam boards and a foam application gun was by far the least expensive.

    If foam contracting prices come down a little I'd probably go that way.
    Until then, the foam DIY options is my preferred choice.
    Swedishchef and Joful like this.
  16. Dana B

    Dana B Feeling the Heat

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    I spoke with an insulation contractor yesterday and he said the going rate to do a basement rim josit job would be anywherr from 300 - 500 or a little more depending on the area. That seems like a very reasonable price to me. I think that would actually be cheaper than doing the spray foam myself from the pricing I've seen for it. The only problem is that he is two hours away from me and does ot travel far for small jobs.
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  17. Joful

    Joful Minister of Fire

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    Similar here, with finding one, but I suspect there are some spray foam contractors near you. Send me your zip code, and I'll Angie's List a few.
  18. velvetfoot

    velvetfoot Minister of Fire

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    He might eventually come out your way.
  19. Dana B

    Dana B Feeling the Heat

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    I already searched Angie's list and there were a few. Some got some bad reviews and I have left massages with others but received no return calls.
    It's such a shame that the less than reputable contractors tarnish the image of the honest ones that want to provide a decent service at a reasonable price.

    Since the guy that quoted me 500 got some good reviews I am going to attempt to talk him into maybe doing my rim joist when he's already scheduled to be in my area for a larger job.
  20. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Sorry, but that is just too funny.
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  21. Joful

    Joful Minister of Fire

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    Since moving from a smaller house to a larger house, I've encountered several instances of contractors quoting me MUCH more to do the same exact job I had done at the last house. I guess they try to gauge how much money you might be willing to hand them, based on your house, the ironic thing being that I actually had much more cash to spend when I lived in the smaller house... now it's tied up in equity.
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  22. Swedishchef

    Swedishchef Minister of Fire

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    What is the going rate for a carpenter your way??
  23. Joful

    Joful Minister of Fire

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    I do most of my own carpentry, but have hired one company do help with refitting old window frames, and their rate is as follows:

    Master: $65/hr
    Journey: $47/hr
    Apprentice: $35'ish (can't remember exactly)

    I think these rates are WAY down, versus 10 years ago. For example, my mason is currently at $65/hour. In 2005 he was at $105/hour, and still turning jobs away.
  24. Dana B

    Dana B Feeling the Heat

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    I've called around and most prices to have a contractor do the spray foam seems to be around 700-800 give or take a little. That definitely seems reasonable.

    The one thing I'd like to ask those of you who've had your rim joist insulated is what was the difference? Did you find that your energy costs dropped? Did the house feel warmer?
    Last edited: Oct 18, 2013
  25. Swedishchef

    Swedishchef Minister of Fire

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    Unfortunately I can't attest to any difference: my house was a new build and I got it done right away.

    However, one would assume it would save a fair amount of money. Think about it: heat rises. If heat can escape or cold air leaks are coming in the basement from on top of the walls (where the rim joist is located), it would be tough to heat. I know that my house ends with 2 @ 2X12s sitting on a gasket on the foundation. Therefore, the concrete is pretty cold and there's only 3 inches of wood keeping the cool air from entering (R value of about 3). I think it would be an effective way to save but I could be wrong.

    I am sure others who have had both uninsulated and insulated will chime in shortly

    Andrew

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