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newbie - not sure which way to go on spray foam insulation

Post in 'The Green Room' started by gtown, Nov 21, 2008.

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  1. gtown

    gtown Member

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    I am a newbie to hearth,.com. This is a great website - been lurking since the spring reading all the faq's, reading reviews and searching the forums for questions. I have not been able to find out enough information to help me with a decision. Here's the info:

    We bought our home in the late spring. We have a 3 season porch that is awesome, but it's a 3 season porch - not much use in the winter in MA. All glass two pane sliders. We decided on getting a pellet stove so we could heat that room and have ambient heat in kitchen and for the room over the garage. Plan on using ceiling fans to distribute heat.

    At the time I was figuring out which stove to go with, I had to deal with other repairs due to moisture damage of having now gutters. When I was able to return to deciding (used cardboard mockups), everybody was ordering pellet stoves. We went with Harman and told I was 240 on the list and not to expect it until March 09. Figured tough luck on my part and was willing to wait for the stove we wanted.

    A couple of weeks ago, got a call from the dealer and our stove would be coming in around Thanksgiving. Had not planned on it, now we have to scramble. The three season porch is over a crawlspace with a concrete foundation and a dirt floor. Clearance from the ground to bottom of floor joist is 22". Access to it is from a larger crawlspace that is under the backhall / bathroom / backhall closet. It also has a concrete foundation with a dirt floor but is about 3 1/2' high from floor to bottom of joist. It has fiberglass insullation, but appears to be hanging lower on the wire hangars. The floors of that area of the house feels a lot colder than the rest of the house. These additions were built in 1990. The main house was build in 1965 and has a full basement with conrete walls and floor.

    I also want the rim joists sprayed at the same time - (if it is not too expensive).

    I want to insulate these two spaces with spray foam insulation. None of the spaces is below grade. I got four bids for the job from four companies. One was a soy based closed cell, one was another closed cell 2lb foam and the remaining two were for Icynene.

    For the same money I could get an R9 rating for the soy based closed cell or go with a R30 rating of the Icynene. For 50% more, I could go with a R19 rating of the other closed cell foam - plus they would do a quick scimcoat down to the plastic liner on the floor.

    I had researched bobvilla, toh, diy on spray foam. When the closed cell vendors were at my house, they said to use closed cell and stay away from open cell because of moisture. When the open cell vendors we at my house, they recommended Icynene, I asked if I needed closed cell because of the space between the ground and the joists under the three season porch. They said no, but added they could spray closed cell if I really wanted to, but it would be 50% more expensive. They said for what I wanted to do, Icynene would do the trick.

    So my struggle comes down to am I better off with a R30 of Icynene open cell spray foam versus the closed cell benefits, but with only a R9 rating.

    We had major amounts of rain this past summer and I did get water in the main basement. This was due to a combination of a lack of hose on the sump pump (now remedied) and no gutters (now remedied too). But I did not get water in the crawl space - higher than the basement floor. So I don't think I will get standing water next to the open cell insulation.

    Sorry for the novel, but wanted to make sure I provided enough information. Thanks in advance! This is a great site - definitely learned a lot, was instrumental in my research of a pellet stove...

    Bob

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  2. BJN644

    BJN644 Feeling the Heat

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    The soy based stuff I had installed (Heatlok Soy) had an R value of 6.5 per inch, if you were quoted R9 they must be using something different or putting it on thin. I have never heard of the other stuff you mentioned and I was also told to stay away from open cell (sponge) foam.
  3. snowtime

    snowtime Minister of Fire

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    I do not have experience with spray foam but my take is you will have condensation under that floor and need the closed foam option. When you start heating the room it will cause more condensation. You do not want mold to start moving up the walls. Seal everything from the moisture in the dirt.
  4. gtown

    gtown Member

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    The soy foam is "biobased 1701" closed cell foam - according to their website...
  5. sgcsalsero

    sgcsalsero Feeling the Heat

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    I think there is a good building science website referenced in some posts here (maybe early this year). I have Icynene in one section of basement but I wouldn't use it near a moisture prone area. I certainly think the sills and between joists is okay, nearer the dirt floor hmmm I don't think so. Again, do a search for building science. I think closed cell is 7.5 R per inch, two inches should do it for basement / crawlspace, or so I recall being told that.

    You are fortunate to have found 4 guys to come out, did they break it down to the cost per board foot ? 12"x12"x1"

    Did they use another way to estimate, I asked one guy last year and didn't break it down despite asking twice. I think based on some calcs I did last year anything in the .40 to .50 cent per board ft. and you are doing ok.

    DIY is not out of the question, however it comes down to pricing, if tiger foam / fomo foam cost 1.25 per bd. ft. and a contractor will do it for 50% less it's a no brainer to me.

    By the way, did any of the contractors quote closed cell that is fire rated . . don't know if there are any code considerations in your neck of the woods
  6. dvellone

    dvellone Feeling the Heat

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    You really should consider putting a vapor barrier on the floor of the crawl space regardless of which way you go with insulation. That's a standard construction practice to prevent damaging moisture when you have a dirt floor in the crawlspace.
    Remember when considering r-values of foam that they are true r-values. R-value measurements when considering fiberglass are based on optimal conditions - no compression of the fiberglass and no air movement through the insulation. As soon as either occurs the r-value can drop significantly. With foam there is no air movement and no compression - R-9 means R-9. With air infiltration and installation that compresses the fiberglass r-19 might drop to r-10 or lower. Air infiltration really causes it to plummet. You might want to think about insulating your foundation walls. No matter how much insulation you dump under the floor it'll still feel cold if the space underneath is frigid. I put r-40 under my floor and until I insulated the walls of the crawlspace you wouldn't have thought there was r-11 under your feet.
  7. gtown

    gtown Member

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    There is plastic sheet already down but probably 4mil - it's pretty beat up, so I will replace it with at least 7 mil. Is it ok to put the new plastic on top of old or will that create layers of slime?

    The guy with the highest bid was going to spray the crawlspace walls 1.5" (R10) from the joists to the plastic on the floor with foam. If I did not go with this bid, I was going to insulate the walls in the crawl space next summer with closed cell and tiger spray - don't think I can keep the 70* temp min for the application. He was the only one who had suggested to spray the walls.

    One thing I did not like about the soybased company was they took their measurements from the outside of the house and to measure the rim joist, they measured the length of each surface. Not sure if this was the method used by the Big Dig Project, but it doubled everyone else in terms the pricing of the rim joist - including the other closed cell company.

    Sorry for the delay in response - last night and this morning's project was to put the pipe insulation on the forced hot water pipes and the hot water pipes.
  8. hankjrfan

    hankjrfan Member

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    I had foam sprayed in between the rafters of an existing deck recently. Didn't think to ask the guy what he was specific type of foam he was spraying. I paid for 1 1/2" but he must have put that stuff 4" thick. Good stuff. Mice or vermin won't nibble at it, no air penetration. Floor is more stable. Worth the money for sure.
  9. sgcsalsero

    sgcsalsero Feeling the Heat

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    strap the spray tanks to a cheap luggage cart, and then wrap the tanks with an electric blanket, one hour at highest setting and you are good to go....keep the blanket on if you can and drag around
  10. gtown

    gtown Member

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    Wow that sounds like a great idea... Will give it some thought.

    As for closed cell vs open cell - I thought that open cell was able to create a relatively air tight barrier. I know that the cells are open and you don't want to have it below grade, but is it that porous that it will absorb water vapor and create an area of mold between the insulation and the subflooring and/or floor joists?

    If I got the closed cell guy to give an R19 layer, could I go back with tiger foam and give it another couple of inches to bring it up to R30? Will new foam adhere to existing foam?

    With that train of thought, if I went with the open cell bid to fill the floor joists, could I go back with the closed cell tiger foam at a later date and skim-coat a layer of the closed cell to seal it?

    For the rim joist band, does it matter if it is closed cell or open cell?
  11. gtown

    gtown Member

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    When I was searching the forum for foam spray before my first post, I tried to connect to the "building science" website via the posted links, but was unable to.

    I thought that they all had to be fire retardent...
  12. d.n.f.

    d.n.f. New Member

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    There is a guy who does soy based spray foam out my way. Are you happy with it? I can't find much on long term comparos soy vs regular foam?

    Everything I have read is that you want closed cell btw. It doesn't break down like open cell.
  13. sgcsalsero

    sgcsalsero Feeling the Heat

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    See http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements, I think there are downloadable .pdfs for free. Also there is a good book called 'Insulate and Weatherize' by Tauton Press.

    I don't think all foam is fire rated, I merely mention as a code consideration (jic say you sell house and someone and the home inspector has a snit), see also below copied from tiger foam. By the way I have Icynene in my basement, I'm not advocating one product over another.
    Tiger Foam® quick curing, disposable, two-component spray polyurethane foam insulation kits are manufactured to ASTM E-84 Specifications and classified as a fire-rated foam insulation. This product is manufactured using the most environmentally friendly blowing agents and fire-retardant chemicals available today and DOES NOT contain CFCs, VOCs, Formaldehyde or PENTA-BDEs. We are the ONLY supplier offering E-84 Fire Rating STANDARD in our surface spray product line. We believe safety is not optional.
  14. stephenmoore

    stephenmoore Member

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    Hey Gtown, what did you end up doing with your spray foam ? I have a 1950's home that I gutted last year and re insulated with Icenyne. The reults were truly impressive. The air barrier is really something. I am a carpenter and on other jobs have since used the "blue" spray foam, (closed cell, 3-M product I think). Up my way people are pricing the two nearly the same. I would totally recomend the closed cell if it's affordable. We have sprayed it over a gravel base and then poured a concrete slab on top. The stuff is totally bomb proof.
    I used to live in a 120 year old house with a 4' dirt floor basement. This is my experience, no matter how much insulation you put in, you need to get a small amount of heat in the space to keep the floor above from freezing you out.
    Let me know how you make out. Also for the money, gluing rigid foam on your foundation works just as well, remember an air barrier below grade where there is no exterior air movement is more of a luxury than necessity.
  15. quinn

    quinn New Member

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    I have Icynene in two buildings and all you would have to do to solve your problem is to spray on the moist side a vapor barrier paint just as they do on the joist ends spaces. This would be a cheap and effective way to get the air seal, high R value and moisture barrier.
  16. sgcsalsero

    sgcsalsero Feeling the Heat

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    What did you pay per board foot? (12" x 12" x 1")

    here's decent guidance on using icynene along with vapor barrier, perhaps a call to local building inspector for your particular situation would be a decent idea http://www.icynene.com/vapor-barriers/
  17. coolidge

    coolidge Member

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    If your floors are above grade the you will need a closed cell foam. Open cell will suck up water like a kitchen sink sponge, thus creating mold at some point. 2" closed cell foam (R-6-7 depending on brand) will give you a vapor barrier. For best results shoot 2" in floor joist and skim the walls. Dont forget the poly for the dirt floor.
  18. gtown

    gtown Member

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    I'm going with the closed cell - it's getting done on Friday - really looking forward to it. Now if I can find someone on the North Shore MA to install the pipe thru the roof, that would be excellent. Would try myself, not sure if I can guarantee no leaks...

    Will let you know how it turns out. Tomorrow night laying out new 6mil black plastic. They will skim coat walls to plastic too.
  19. Hankovitch

    Hankovitch Member

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    Hello,
    Hankovitch here. Been a visitor at "Hearth" for some time, saw this thread, and felt compelled to make a lengthy contribution.
    Whenever any possibility of the presence of moisture - use closed cell foam.
    Personally I prefer non-soy-based foam. Non-soy-based foam will have zero nutritional value to any living organism, from bacteria and molds to rodents....thus, my choice. If your GREEN(er??) foam insulation is eaten by rodents or metabolized by microbes then your insulation is gone, you use more fossil fuels to heat your space, and you are no longer "Green"!

    By the way, if you use closed cell foam you may eliminate the use of any plastic. Don't pay for it, don't pay for its installation. It will NOT be needed. For compelling information confirming this (don't just take my word for it), see the Canadian Article below.

    Below is information on spraying foam on concrete, outside, above grade to 2 feet below grade. A 2.5 year study in Canada.
    I include a link to the entire article. Pretty compelling information, extremely well done study, great science.

    This is lengthy, but hopefully helpful..................

    Link to the Canadian Article about functionality and integrity of SPF applied directly to concrete above and below grade to outside of a building...

    http://www.cufca.ca/research/Basement Insulation Report -IR820-English.pdf
    NOTE: The above link does not 'work'..... here is an EDIT to the original email, with a workable path to the article.
    1. Plug the following into your browser (I used GOOGLE)
    nrc-cnrc eibs in-situ
    2. Look for the following, and “click” on it.
    File Format: PDF/Adobe Acrobat
    This report summarises the findings of the project “In-situ Performance. Evaluation of Exterior Insulation Basement System (EIBS) - Spray Polyurethane ...

    In my extensive research on using SPF as the outermost part of the building envelope I have seen where they measure the actuall R-value of the BUILDING after it is all up and running. It is a simple experiment and calculation - monitor temp inside the building and outside the building over some predetermined length of time (say 24 hours), and determine how many btu of energy (btu per min X total min furnace burned per the 24 hours) were required during that time ( 24 hours) to maintain the measured inside/outside temperature differential. Plug numbers into an equation and out pops "R-value" of the structure.

    Interestingly, R-values for the entire structure are determined to be between 60 and 80! The reasons are....

    (a) since the building is surrounded by a closed cell foam, the entire building stays at the inside temp set by the thermostat, and the entire building thus functions as a huge heat sink. Pretty aswsome....and

    (b) the self-flashing nature of the SPF means that there are NO holes in the skin you put on the building, NO air leaks. ALL the holes you put in the roof and siding are sprayed with foam AFTER you are done with the siding, vents, windows, doors installation. Think about it, after you put on your excellent Tyvek product which is supposed to function as your vapor barrier you then put on your siding and your trim - after you put up your vapor barrier you punch several thousand holes in it! - where is the 'wisdom' here?! (Wow, I sure rambles on, didn't I?

    As with the information demonstrating the integrity and functionality of the SPF applied to a building above and below grade and the published article from Canada...(link above), I will see if I can find the link to any of the reports which describe this (admittedly unbelievable at first blush) astronomical R-value.

    I did find one link regarding insulating by spraying on the outside of a concrete building...., Here is an excerpt from the article, and then link to the entire article.

    ***************************************************************************

    Thermal Diffusivity and Heat Sinks

    It should be noted that when the urethane is used on the exterior of a heat sink, such as concrete, the actual effective R-value is approximately doubled. This is why with the Monolithic Dome, we are able to calculate effective R-values in excess of 60. A heat sink is any substance capable of storing large amounts of heat. Most commonly we think of concrete, brick, water, adobe and earth as heat sink materials used in building. The property of a heat sink to act as an insulation is called thermal diffusivity.

    The simple explanation for the way it works is: As the temperature of the atmosphere cycles from cold to hot to cold to hot the heat sink absorbs or gives up heat. But because the heat sink can absorb so much heat it never catches up with the full range of the cycle. Therefore, the temperature of the heat sink tends to average. Large heat sinks will average over many days, weeks or even months.

    An example is the adobe hacienda with its 2 to 6 foot thick walls. By the time the adobe walls begin to absorb the daytime heat it is night time and the same heat then escapes into the cooler night. Therefore the temperature would average. Because the mass of the adobe is so large the temperature averages over periods of months. Adobe acts as an insulation even though adobe has a minimal “R” value.

    You can see from the graph that urethane thicknesses beyond four or five inches is practically immaterial. We use three inches for most of our construction. Two inches will do a very superior job. We have insulated many metal buildings with one inch of urethane and the drop in heat loss is absolutely dramatic. Obviously the first quarter inch takes care of the wind blowing through the cracks. (It usually takes an inch to be sure the cracks are all filled.) The balance of the inch adds the thermal protection.

    http://www.bestsprayfoam.com/R_Value_myth.htm

    Finally...........please communicate with me if you have experience with Sprayed Polyurethane Foam applied to the outside of a building, then covered with an elastomeric paint ---- this then functions as a combination insulation/roofing/siding/water barrier/vapor barrier. We plan to do this with our Barn-to-Home conversion.
    I'd like to hear from you, as a reply here to share with all, and/or personally at the below email.

    Sincerely,

    Hankovitch
    hdaum@tds.net
  20. Hankovitch

    Hankovitch Member

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    Trying again to get the complete, working link to that article on study done in Canada.....SPF above and below grade, on concrete foundation.

    http://www.cufca.ca/research/Basement Insulation Report -IR820-English.pdf

    Sincerely,

    Hank
  21. d.n.f.

    d.n.f. New Member

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    Have heard some rumours that a lot of this spray foam will be made illegal due to isocyanides or something. Soy-foam is not part of the ban.

    Could be a vicious rumour from the soy industry.
  22. Hankovitch

    Hankovitch Member

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    Hello Nelson,
    I think the spray foam ban is apocryphal / urban legend. Yes, some 'foams' did have foamaldehyde in them. They were banned and have not been used for a few decades now. There are no "cyanates" in poly"urethane". Polymerization is complete in seconds, and the foam may be walked on in 120 seconds. There is a wealth of information on how safe Closed-cell Polyurethane is.
    And now for a way to get to that Canadian article.
    1. Plug the following into your browser (I used GOOGLE)
    nrc-cnrc eibs in-situ
    2. Look for the following, and "click" on it.
    File Format: PDF/Adobe Acrobat
    This report summarises the findings of the project “In-situ Performance. Evaluation of Exterior Insulation Basement System (EIBS) - Spray Polyurethane ...

    Sincerely,

    Hank
  23. d.n.f.

    d.n.f. New Member

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    Just talked to two spray foam guys (one soy based and one not). Both mentioned it. Just passing the rumour along. They both said it was in the US not Canada. No idea where they got their information from.
  24. gtown

    gtown Member

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    Hank,

    We are having closed cell spray foam sprayed on the underside of the floor joists (in the crawlspace) in three crawlspaces. In addition, they are doing the rim joist in the full height concrete floor basement where the utilities are. Two of the crawlspaces are a dirt floor. There currently is plastic over the floor but it looks 4mil and used and abused, the other one is the 22" (5cm) crawlspace height with no plastic. The owner of the company who came to the house, said I should replace that with 6mil plastic and have it overlap the walls and he would scim-coat the concrete walls down to this plastic on the floor. There is no plastic between the foam and the underside of the floor joist acting as a vapor barrier.

    Is this the right thing to do?

    I'll try to read the article, but I need to finish clean/organize the basement as prep for the job...

    Thanks,

    Bob
  25. d.n.f.

    d.n.f. New Member

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    Only going to say that six mill is the way to go. 4 is too wimpy. You can walk on 6mm.
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