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  • Polyurethane Foam Insulation

    I'm planning to insulate my garage and am looking into polyurethane foam insulation - the kind that is sprayed. I've heard some very positive things but some of the information I've found on the web indicates that, contrary to popular opinion, the foam is not a perfect moisture barrier and the insulation properties degrade over time. So, I thought I'd ask the experts on the forum. Is this an option I should consider for my garage? I have a contractor coming to give me an estimate this Thursday. I believe that after the foam is blown in place between the studs I just drywall over top (no vapor barrier required). I'd really appreciate hearing what you have experienced or know about this product. Thanks, Andrew

  • #2
    Re: Polyurethane Foam Insulation

    I had this one in my favorite/bookmarks, this one is right up your alley. Read this thoroughly and it will help you with everyone of your questions. You should save this in your bookmark for future friends and family who may also be interested. I don't see to many H.O. (Home Owners) that will go with this product for a garage. Unless your heating and cooling 24/7, most just go with blanket insulation.

    Hahaha, I forgot to post this site, just saw the mistake, in Canada, this is what you want...

    http://www.beickerinsulation.com/Icy...d-Answers.html
    Last edited by garager; 10-21-2007, 10:02 AM.
    Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

    http://www.contractorspub.com

    A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

    Comment


    • #3
      Re: Polyurethane Foam Insulation

      http://www.hurricanefoamseal.com/ when i bought my home here in florida this is what i used to get a muuuucccccccch better rate on my insureane, this did cost quite abit though. i am not sure if it is the same thing or not
      9/11/01, never forget.

      Comment


      • #4
        Re: Polyurethane Foam Insulation

        Thanks guys. Oldslowchevy, the stuff you are talking about is to prevent water from getting into the house. The material is polyurethane but it seems to be for a different purpose than what I need. I'm not concerned with moisture getting as I am about heat escaping in the winter.
        Garager, thanks for the link. It looks like the kind of thing I need. It is a different material, Icynene. When you referred to "blanket insulation" I take it this is the pink glass stuff?

        Comment


        • #5
          Re: Polyurethane Foam Insulation

          Originally posted by athuswal View Post
          . When you referred to "blanket insulation" I take it this is the pink glass stuff?
          Yes, and with the paper backing on it, for walls. Ceilings you can go without the paper, but then some might argue on that....

          Or white blanket, which is formaldehyde free......
          Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

          http://www.contractorspub.com

          A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

          Comment


          • #6
            Re: Polyurethane Foam Insulation

            Just from attic adventures I have been in some nice houses with spray foam insulation in the roof.....attics were not all that hot....actualy pretty nice to work in dureing the florida summer heat....sooo I was always impressed.

            Delt with 2 home owners who used the foam block....with pured cement construction on their house....ends up with solid concrete walls, with foam on both sides....who claimed too have seriously low ligth bills....

            I dont know how ever....how well the hold up long term...or VOC contamanation and such...but seem too keep the house's cool.

            Comment


            • #7
              Re: Polyurethane Foam Insulation

              Originally posted by Evil Gopher View Post
              Just from attic adventures I have been in some nice houses with spray foam insulation in the roof.....attics were not all that hot....actualy pretty nice to work in dureing the florida summer heat....sooo I was always impressed.

              Delt with 2 home owners who used the foam block....with pured cement construction on their house....ends up with solid concrete walls, with foam on both sides....who claimed too have seriously low ligth bills....

              I dont know how ever....how well the hold up long term...or VOC contamanation and such...but seem too keep the house's cool.
              Indeed it does hold up well, the concrete walls that is, but must be done properly. This style is being used here in Mn. all over now.

              The cost for the spray foam, is very high, so for being in a garage, well lets just say, it must be nice to have extra money. In a home, I would highly recommend this, but certain areas in the world or just the states get a different type, however there isn't many different types. There is even a soy spray foam.

              Spraying the foam between trusses, also strengthens the roof structure, which could save your house in a Hurricane or a close pass from a Tornado. There are many other pluses/reasons for using this type of insulation, besides the awesome R value you get. Wish my house had it...
              Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

              http://www.contractorspub.com

              A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

              Comment


              • #8
                Re: Polyurethane Foam Insulation

                If you spray it between the trusses, does it reduce the life of the shingles because the air can't cool the underneath side of the roof during the direct sunlight? May not be a big problem in MN but could be a major player in FL. Just blocking the eaves vents could reduce shingle life by about 40%.

                Go
                Practicing at practical wood working

                Comment


                • #9
                  Re: Polyurethane Foam Insulation

                  they install some foam "breathers" on the center of each run witch is 8" wide and from the eve to the peak . that allows for the air flow. trust me i thought the same thing but my roof is tile so i am not sure what the effects it will have
                  9/11/01, never forget.

                  Comment


                  • #10
                    Re: Polyurethane Foam Insulation

                    Regarding the spray-in insulation and a moisture barrier.

                    Please keep in mind that not all spray-in insulation is the same. There are many flavors of products available (figuratively speaking) but most fall into 2 overarching categories:

                    OPEN CELL: Basically stops the movement of air (air barriers are extremely important with respect to insulation) and slows the transfer of heat. Open cell is NOT regarded as a vapor barrier/retarder (see below).

                    CLOSED CELL: These foams, depending on thickness, may be considered a vapor retarder but not a vapor barrier (there is a difference... basically anything with a perm rating or 1.0 or less is considered a vapor barrier). Closed cell foams also have a high compressive strength which allows them to be used for exterior applications.


                    Most all of the commercially available foams carry a Class A rating for smoke and flame which is suitable for most residential building jurisdictions. Do check with your local building officials though...


                    With respect to the roofing and the spray foam applied to the underside of the decking - depending on your location this may be a VERY bad idea. Climate zones which are considered hot and humid (i.e. Houston, New Orleans) do not bode well for most roof spray applications due to the moisture loads, drying capacities, etc. There are also considerations of the roofing materials themselves. A shingle/comp roof can't dry as efficiently as a clay/concrete "S" tile roof. An application of spray foam on a tile roof has a higher potential for success than others.

                    That said you can construct your roof differently (again depending on geography and available and sensible materials) to accommodate a sprayed roof.

                    Another consideration - if you plan on moving the insulation from the ceiling floor to the underside of the roof, you have effectively 'cathedralized' your home... you have moved the thermal boundary to the roof. Doing so now brings any and all things in the attic space into the living area. If you have a heater, air handler, water heater, etc. in your attic and they are combustion appliances your exposure to RISK has increased. These units need to be sealed combustion (not using house air) or have a dedicated path for combustion air. The odds of these back drafting has increased greatly.

                    Please note - retrofitting your existing home with products that were not originally installed can give you some VERY bad results! Be VERY careful doing this and consult with a local building official or building science expert. PM me for contacts in this arena.

                    Best of luck!

                    Comment


                    • #11
                      Re: Polyurethane Foam Insulation

                      just cruising the forum here and found this thread. being a spf installer for ten years i cant help but put in my 2 cents here.

                      first, let me tell you that icynene is not a type of foam. it is a brand, just like weedeater is not the tool. and while i have no problems with thier product, many in the buisness have issues with thier marketing techniques. icynene ia an open celled, half pound foam. nothing more.

                      the first thing one needs to consider before choosing a foam is wether to use open or closed cell foam. without getting to technical, open is a soft foam, and closed is a rigid foam. oc foams typicaly have an r value around 3.5 per inch. can reduce ur heating cooling cost by half. and providing a better sound barrier than cc foam. and it usualy cost around 25% less than cc. cc, or rigid foams are usualy a 2.0 pcf foam and have an r value around 6.75 per inch. unlike the soft foams, cc dries to a hard plastic and filling the area between the studs with a couple inches of foam will double the racking stregnth of the wall. and application between roof joist will stregthen the roof 2-4 x's, respectively. it will also bond the structure together and resist lift just like the hurricane adhesive (the hurricane adheasive is basicaly cc foam applied only to the joist decking seam). since i have never seen a closed cell foam with a perm rating of greater than 1 i will go ahead and call it a vapor barrier. a very real advantage to the unvented attic system is that you have an extra layer of water protection. in hurricane katrina we lost most every shingle on the house and had no water intrusion. this is especialy comforting since most insurers here no longer cover wind driven rain. wether in a wall, over a ceilind, or under a roof deck, cc foam is a vapor barrier and stops the moisture drive eliminating the neccessary component for the formation of mold and mildew

                      many peeps are uncomfortable with the unvented attic system cause uninformed builders tell them that an attic needs to breath. and with an uneffective insulator such as fiberglass or cellulose this is true. if it werent ventilated the respective dew point would cause condensation and severe moisture problems. with an effective building envelope that uses an air barrier system, the dew point is never reached inside the envelope, so condensation can not happen. and i can tell you that this system is especially beneficial in the warmer climates such as the hot and humid south where attic temps regularly exceed the 150 degree mark in the summer. an unvented attic will stay within 5-8 degrees of ur living space. leaving ur duct work in a much milder enviorment (bonus=ur attic is now climate controlled storage)but, if ur not comfortable with current technoligy, this stuff works just as well sprayed down on ur ceiling protecting you from the hot, moist oven radiating above. it does however increase shingle temps by 5 degrees and shingle companies, the same guys who make the fiberglass insulation, say it will void the warranty.have you ever heard of them honoring a warranty? even once?

                      another common type of foam is roofing foam. it is usualy 2.5=3.5 pound foam and is always closed cell. after instalation this product, like any spf, must have a protective coating such as a polyaurea or other approved coating applied. sunlight will deteriate foam.

                      all spf's are class a fire rated, wich is the highest rating available for any insulation. it does however require an ignition barrier (15 minute burn such as sheetrock...)in any area that may be occupied by humans.

                      while there are many differences in oc and cc foam, foams are basicaly the same from brand to brand. what counts is the quality of the installation. you are paying for an air barrier system. not just some dude to spray some stuff in ur walls.this involves a lot of drilling , caulking, single compound foaming, (you want those windows and doors to open and close properly) and cleaning up. and these guys can do a lot to save time and money. a set of chemical cost me 2 grand and it will yeild 4000 board feet. with my knowledge i can stretch it to 6000 with a few minor alterations to the surfactant. and you would never know. but it would weeken the foam. some guys spray thin in places where they think you wont check. and with closed cell, no more than 2 inches at a time. it is a lot easier to spray thicker and finish in one coat. but, this will build too much heat and weaken the foam. and you would never know the difference. unless, it catches fire and burns ur house down. the lowest bidder, not always the right guy!

                      and hire the right hvac guy. make sure he can do a manual j. bigger is not better. ur unit needs to run long enough to pull humidity from the air. not constantly turn on and off. these things use a lot more energy to start than to run. and your house goes from hot to cold. comfort and efficient are the same. anything that makes ur home more comfortable will inherintly save you $. so go ahead and get some good windows and doors. this is part of a system. go all out and cut ur power bill 60-70%

                      expensive? spf typically cost 2-3 times what fiberglass does. so yeah, it cost more. more than 40% of this countries energy is used for heating and cooling residential buildings. yet, we will spend more on our driveways than we will on insulating our home? based on an average 2400 square foot home you are looking at about $8500. thats about $28 a month on ur mortagae. and it cuts ur energy bills in half. so you are actualy saving $80-$150 every month. is it realy expensive? plus the right size hvac is half what you would need without spf. so you save more. then uncle sam sends you 2 g's at the end of the year for being smart! then when you go to sell and ur electric bills sell ur house for you... and if thats not enough, google energy efficeint mortages, and then tell me how you can afford not to be way more comfortable.

                      and my wifes favorite thing about spf, since we keep all the unconditioned, polluted air out, she only has to dust maybe 2 or 3 times a year!

                      Comment


                      • #12
                        Re: Polyurethane Foam Insulation

                        I took this pic two days ago in an attic. It was over 105 degrees outside with the heat index and the sun was shining full force. It was about 80 degrees in the attic.......the foam works my friend.

                        I'm considering getting done to my house after walking around in that atttic for 10 minutes and not breaking a sweat,

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                        • #13
                          Re: Polyurethane Foam Insulation

                          how does it effect the life of the roof shingles ,if it does not effect them then that very good to have this done
                          Charlie

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                          http://observatory.mountwashington.o...nal&fr_id=1040


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                          new work pictures 12/09
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                          • #14
                            Re: Polyurethane Foam Insulation

                            We see a lot of this in our area, even work with one of the installation companies, we have them foam under our nailup radiant installs.

                            It's nearly a joy to work in an attic like the one themaster posted a pic of. The only concern I have is that wood needs to breathe, or it rots. kinda hard to breathe through a poly barrier.

                            This is the same thing that gets done on some of the multimillion dollar homes in our area "that's expensive here"
                            No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

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                            • #15
                              Re: Polyurethane Foam Insulation

                              Originally posted by Gofor View Post
                              If you spray it between the trusses, does it reduce the life of the shingles because the air can't cool the underneath side of the roof during the direct sunlight? May not be a big problem in MN but could be a major player in FL. Just blocking the eaves vents could reduce shingle life by about 40%.

                              Go
                              Right. Actually, some people do not realize one of the main functions of a well-ventilated attic (plenty of soffit vents, ridge vent, gable vents, etc.) is to act as a heat sink for the roof above. Not only the shingles, but also the wooden sheathing under the shingles. I know of one contractor who discovered that a Florida home (I live in Florida, too) that had thick foam insulation sprayed on the underside of the roof a few years before ended up with some serious deterioration problems, even if the attic itself had been kept cooler. When the roof was reshingled they discovered that the plywood underneath had been literally "cooked" to the point where the layers were no longer sticking to each other. They could be peeled away like onion skin. The plywood glue had been crystalized by the heat.

                              So, yes, insulating foam sprayed under the roof surface will keep the attic cooler, but in doing that the roofing material (both shingles and wood sheathing) get roasted, since the heat-sink function of the attic no longer is available.

                              Howard Ferstler

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