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Re: [hreg] Re: Radiant Heat Shield

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  • WGAS Racing
    What about a flat roof? I have one that is constructed using a plywood over joists, then urethane foam, topped off with a white elastomeric coating. Can the
    Message 1 of 11 , Feb 6, 2003
      What about a "flat" roof? I have one that is
      constructed using a plywood over joists, then urethane
      foam, topped off with a white elastomeric coating.
      Can the addition of an foil-like material to the
      underside of the plywood improve anything for me.

      I'm told by my roofing company that the minimum roof
      thickness for my roof is about 4".

      Rob
      Seabrook, TX

      --- "mark r. johnson <mrj53@...>"
      <mrj53@...> wrote:
      > Chris, what I have clearly been hearing is these
      > methods work. The one
      > that seems most unlikely to you, attaching this
      > foil-like material to
      > the underside of the roof decking, is to the best of
      > my knowledge the
      > most effective method for adding to an existing
      > home. Of course if you
      > are building new construction, or re-roofing and can
      > consider
      > replacing the decking, you probably would find it
      > better to buy the
      > kind of
      > roof decking that has the foil underside.
      >
      > Evidently the shiny side must face an air space for
      > it to work. The
      > downside of laying the barrier horizontally on
      > existing attic
      > insulation, is that it works fine the first day, but
      > it soon will get
      > dusty and become less effective.
      >
      > Usually we assume asphalt shingles when we talk
      > about radiant
      > barriers. If you happen to have a different roof
      > material, we ought to
      > stop and reconsider. I have read that tile roofs
      > have advantages which
      > lessen the effectiveness of radiant barriers and
      > attic ventilation.
      > Probably metal roofs as well.
      >
      > It is my understanding that spray-on radiant barrier
      > paint cannot be
      > as reflective as foil stapled to roof rafters or on
      > decking material,
      > but its ease of use may be attractive for retro-fit
      > jobs. Tom Tynan
      > endorses spray-on radiant barrier paint on the
      > underside of your roof
      > decking:
      > http://tomsangle.com/docs/Radiant.pdf
      > So far as I can tell, Tom agrees that foil based
      > roof decking is
      > superior for new construction. I believe stapling
      > foil type material
      > to the rafters, will provide superior performance
      > but it might be so
      > much extra labor that costs outweigh the benefits.
      >
      > You might find the following article from the
      > Florida Solar Energy
      > Center (FSEC) interesting. All that I have seen from
      > FSEC appears high
      > quality practical research, in my opinion:
      > http://www.fsec.ucf.edu/bldg/pubs/pf337/
      >
      > I must say that I am a total amateur and am merely
      > passing along
      > things I have been taught which sound right. Am
      > thinking about putting
      > up foil type radiant barrier in my house but have
      > not done the project
      > yet. Am somewhat thinking about retro-fitting "skin
      > venting" to our
      > exterior walls but first must find someone with
      > professional
      > credentials who will endorse such a project. If
      > anyone finds fault
      > with what I have said, it will be to everybody's
      > benefit to correct
      > me.
      >
      > Thanks and good luck -- Mark J.
      >
      >
      >
      >
      >
      > --- In hreg@yahoogroups.com, "Roxanne Boyer"
      > <rox1@a...> wrote:
      > > I am looking for ways to reduce the cooling energy
      > costs of my home.
      > I have heard about radiant heat barriers in the
      > form of:
      > > 1) Exterior coatings (put on the paint or
      > shingles) that reflect
      > solar radiation.
      > > 2) Foils that are applied to the underside of the
      > roofing board -
      > either sprayed or stapped in sheets - that reflect
      > infared radiation.
      > > 3) Foils that cover the attic floor on top of the
      > insulation that
      > also reflect infared radiation.
      > >
      > > Does anyone have any experience with these
      > applications? Do they
      > work? How much does it cost to have them installed?
      > >
      > > Theoretically the radiant barrier on the exterior
      > of the roof and
      > the radiant barrier on the attic floor should work.
      > I don't see how
      > the foil/spray on the bottom of the roof could work.
      > >
      > > Chris Boyer
      > > "Conservation is a great alternative fuel."
      >
      >


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      Plastics Engineer
      IVA Flight Crew Equipment
      HEI/Lockheed Martin
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    • Robert Johnston
      For what it s worth, I did this job myself a couple years ago. I did it really cheap: I just bought heavy duty aluminum foil at the grocery store (the thick
      Message 2 of 11 , Feb 6, 2003
        For what it's worth, I did this job myself a couple years ago. I did it
        really cheap: I just bought heavy duty aluminum foil at the grocery
        store (the thick gage for barbeque etc., not the thinner gage) and
        stapled it to the rafters in my attic. I think it feels noticeably
        cooler in the attic, but I can't tell you I noticed any difference on my
        air conditioning bill. But I also changed some equipment in my AC
        system at nearly the same time.

        Just don't be crazy like me and get the idea of saving money on AC in
        July! Even though I only worked in the mornings, I tended to work too
        long into the day, and nearly passed out from the heat even with lots of
        water. Do it now instead! And wear long sleeves to protect from the
        fiberglass insulation if you have it.

        Robert


        > -----Original Message-----
        > From: houtextml <dlagrone@...>
        [mailto:dlagrone@...]
        > Sent: Thursday, February 06, 2003 8:37 AM
        > To: hreg@yahoogroups.com
        > Subject: [hreg] Re: Radiant Heat Shield
        >
        > Here are a couple of good info links for you;
        >
        > http://www.ornl.gov/roofs+walls/radiant/
        >
        > http://www.heatbarrier.com/
        >
        > http://www.u-b-kool.com/
        >
        > I may be tackling this project myself Roxanne. If you'd like to buy
        > in bulk, help with each other's install or just chat about the topic,
        > drop me an email.
        >
        > Cheers,
        >
        > Doug
        >
        > --- In hreg@yahoogroups.com, "Roxanne Boyer" <rox1@a...> wrote:
        > > I am looking for ways to reduce the cooling energy costs of my
        > home. I have heard about radiant heat barriers in the form of:
        > > 1) Exterior coatings (put on the paint or shingles) that reflect
        > solar radiation.
        > > 2) Foils that are applied to the underside of the roofing board -
        > either sprayed or stapped in sheets - that reflect infared radiation.
        > > 3) Foils that cover the attic floor on top of the insulation that
        > also reflect infared radiation.
        > >
        > > Does anyone have any experience with these applications? Do they
        > work? How much does it cost to have them installed?
        > >
        > > Theoretically the radiant barrier on the exterior of the roof and
        > the radiant barrier on the attic floor should work. I don't see how
        > the foil/spray on the bottom of the roof could work.
        > >
        > > Chris Boyer
        > > "Conservation is a great alternative fuel."
        >
        >
        >
        >
        > Your use of Yahoo! Groups is subject to
        http://docs.yahoo.com/info/terms/
        >
        >
      • Mike Ewert
        The foil or paint under the rafters works because the emissivity is low; even though the foil itself gets hot, it doesn t radiate much heat. My AC guy said
        Message 3 of 11 , Feb 9, 2003
          The foil  or paint under the rafters works because the emissivity is low; even though the foil itself gets hot, it doesn't radiate much heat.  My AC guy said he used the paint in his metal building shop and really noticed a difference.
          -----Original Message-----
          From: mark r. johnson <mrj53@...> [mailto:mrj53@...]
          Sent: Thursday, February 06, 2003 1:39 PM
          To: hreg@yahoogroups.com
          Subject: [hreg] Re: Radiant Heat Shield

          Chris, what I have clearly been hearing is these methods work. The one
          that seems most unlikely to you, attaching this foil-like material to
          the underside of the roof decking, is to the best of my knowledge the
          most effective method for adding to an existing home. Of course if you
          are building new construction, or re-roofing and can consider
          replacing the decking, you probably would find it better to buy the
          kind of
          roof decking that has the foil underside.

          Evidently the shiny side must face an air space for it to work. The
          downside of laying the barrier horizontally on existing attic
          insulation, is that it works fine the first day, but it soon will get
          dusty and become less effective.

          Usually we assume asphalt shingles when we talk about radiant
          barriers. If you happen to have a different roof material, we ought to
          stop and reconsider. I have read that tile roofs have advantages which
          lessen the effectiveness of radiant barriers and attic ventilation.
          Probably metal roofs as well.

          It is my understanding that spray-on radiant barrier paint cannot be
          as reflective as foil stapled to roof rafters or on decking material,
          but its ease of use may be attractive for retro-fit jobs. Tom Tynan
          endorses spray-on radiant barrier paint on the underside of your roof
          decking:
          http://tomsangle.com/docs/Radiant.pdf
          So far as I can tell, Tom agrees that foil based roof decking is
          superior for new construction. I believe stapling foil type material
          to the rafters, will provide superior performance but it might be so
          much extra labor that costs outweigh the benefits.

          You might find the following article from the Florida Solar Energy
          Center (FSEC) interesting. All that I have seen from FSEC appears high
          quality practical research, in my opinion:
          http://www.fsec.ucf.edu/bldg/pubs/pf337/

          I must say that I am a total amateur and am merely passing along
          things I have been taught which sound right. Am thinking about putting
          up foil type radiant barrier in my house but have not done the project
          yet. Am somewhat thinking about retro-fitting "skin venting" to our
          exterior walls but first must find someone with professional
          credentials who will endorse such a project. If anyone finds fault
          with what I have said, it will be to everybody's benefit to correct
          me.

          Thanks and good luck -- Mark J.





          --- In hreg@yahoogroups.com, "Roxanne Boyer" <rox1@a...> wrote:
          > I am looking for ways to reduce the cooling energy costs of my home.
          I have heard about radiant heat barriers in the form of:
          > 1) Exterior coatings (put on the paint or shingles) that reflect
          solar radiation.
          > 2) Foils that are applied to the underside of the roofing board -
          either sprayed or stapped in sheets - that reflect infared radiation.
          > 3) Foils that cover the attic floor on top of the insulation that
          also reflect infared radiation.
          >
          > Does anyone have any experience with these applications?  Do they
          work?  How much does it cost to have them installed?
          >
          > Theoretically the radiant barrier on the exterior of the roof and
          the radiant barrier on the attic floor should work.  I don't see how
          the foil/spray on the bottom of the roof could work.
          >
          > Chris Boyer
          > "Conservation is a great alternative fuel."


          Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
        • Robert Bruce Warburton
          I found a web site from a Danish group similar to the HREG, but concentrating on windpower. The Danes make the greatest use of windpower as far as I have read.
          Message 4 of 11 , Feb 9, 2003
            I found a web site from a Danish group similar to the HREG, but concentrating on windpower. The Danes make the greatest use of windpower as far as I have read. Mike what have you heard about the Russian shuttle Buran? No one is mentioning the Buran which had just one launch.

            Mike Ewert wrote:

             The foil  or paint under the rafters works because the emissivity is low; even though the foil itself gets hot, it doesn't radiate much heat.  My AC guy said he used the paint in his metal building shop and really noticed a difference.
            -----Original Message-----
            From: mark r. johnson <mrj53@...> [mailto:mrj53@...]
            Sent: Thursday, February 06, 2003 1:39 PM
            To: hreg@yahoogroups.com
            Subject: [hreg] Re: Radiant Heat Shield
             
            Chris, what I have clearly been hearing is these methods work. The one
            that seems most unlikely to you, attaching this foil-like material to
            the underside of the roof decking, is to the best of my knowledge the
            most effective method for adding to an existing home. Of course if you
            are building new construction, or re-roofing and can consider
            replacing the decking, you probably would find it better to buy the
            kind of
            roof decking that has the foil underside.

            Evidently the shiny side must face an air space for it to work. The
            downside of laying the barrier horizontally on existing attic
            insulation, is that it works fine the first day, but it soon will get
            dusty and become less effective.

            Usually we assume asphalt shingles when we talk about radiant
            barriers. If you happen to have a different roof material, we ought to
            stop and reconsider. I have read that tile roofs have advantages which
            lessen the effectiveness of radiant barriers and attic ventilation.
            Probably metal roofs as well.

            It is my understanding that spray-on radiant barrier paint cannot be
            as reflective as foil stapled to roof rafters or on decking material,
            but its ease of use may be attractive for retro-fit jobs. Tom Tynan
            endorses spray-on radiant barrier paint on the underside of your roof
            decking:
            http://tomsangle.com/docs/Radiant.pdf
            So far as I can tell, Tom agrees that foil based roof decking is
            superior for new construction. I believe stapling foil type material
            to the rafters, will provide superior performance but it might be so
            much extra labor that costs outweigh the benefits.

            You might find the following article from the Florida Solar Energy
            Center (FSEC) interesting. All that I have seen from FSEC appears high
            quality practical research, in my opinion:
            http://www.fsec.ucf.edu/bldg/pubs/pf337/

            I must say that I am a total amateur and am merely passing along
            things I have been taught which sound right. Am thinking about putting
            up foil type radiant barrier in my house but have not done the project
            yet. Am somewhat thinking about retro-fitting "skin venting" to our
            exterior walls but first must find someone with professional
            credentials who will endorse such a project. If anyone finds fault
            with what I have said, it will be to everybody's benefit to correct
            me.

            Thanks and good luck -- Mark J.
             
             
             
             

            --- In hreg@yahoogroups.com, "Roxanne Boyer" <rox1@a...> wrote:
            > I am looking for ways to reduce the cooling energy costs of my home.
            I have heard about radiant heat barriers in the form of:
            > 1) Exterior coatings (put on the paint or shingles) that reflect
            solar radiation.
            > 2) Foils that are applied to the underside of the roofing board -
            either sprayed or stapped in sheets - that reflect infared radiation.
            > 3) Foils that cover the attic floor on top of the insulation that
            also reflect infared radiation.
            >
            > Does anyone have any experience with these applications?  Do they
            work?  How much does it cost to have them installed?
            >
            > Theoretically the radiant barrier on the exterior of the roof and
            the radiant barrier on the attic floor should work.  I don't see how
            the foil/spray on the bottom of the roof could work.
            >
            > Chris Boyer
            > "Conservation is a great alternative fuel."
             

            Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


            Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

          • Mike Ewert
            http://liftoff.msfc.nasa.gov/rsa/buran.html ... From: Robert Bruce Warburton [mailto:warbur2@ev1.net] Sent: Sunday, February 09, 2003 5:16 PM To:
            Message 5 of 11 , Feb 9, 2003
              -----Original Message-----
              From: Robert Bruce Warburton [mailto:warbur2@...]
              Sent: Sunday, February 09, 2003 5:16 PM
              To: hreg@yahoogroups.com
              Subject: Re: [hreg] Re: Radiant Heat Shield

              I found a web site from a Danish group similar to the HREG, but concentrating on windpower. The Danes make the greatest use of windpower as far as I have read. Mike what have you heard about the Russian shuttle Buran? No one is mentioning the Buran which had just one launch.

              Mike Ewert wrote:

               The foil  or paint under the rafters works because the emissivity is low; even though the foil itself gets hot, it doesn't radiate much heat.  My AC guy said he used the paint in his metal building shop and really noticed a difference.
              -----Original Message-----
              From: mark r. johnson <mrj53@...> [mailto:mrj53@...]
              Sent: Thursday, February 06, 2003 1:39 PM
              To: hreg@yahoogroups.com
              Subject: [hreg] Re: Radiant Heat Shield
               
              Chris, what I have clearly been hearing is these methods work. The one
              that seems most unlikely to you, attaching this foil-like material to
              the underside of the roof decking, is to the best of my knowledge the
              most effective method for adding to an existing home. Of course if you
              are building new construction, or re-roofing and can consider
              replacing the decking, you probably would find it better to buy the
              kind of
              roof decking that has the foil underside.

              Evidently the shiny side must face an air space for it to work. The
              downside of laying the barrier horizontally on existing attic
              insulation, is that it works fine the first day, but it soon will get
              dusty and become less effective.

              Usually we assume asphalt shingles when we talk about radiant
              barriers. If you happen to have a different roof material, we ought to
              stop and reconsider. I have read that tile roofs have advantages which
              lessen the effectiveness of radiant barriers and attic ventilation.
              Probably metal roofs as well.

              It is my understanding that spray-on radiant barrier paint cannot be
              as reflective as foil stapled to roof rafters or on decking material,
              but its ease of use may be attractive for retro-fit jobs. Tom Tynan
              endorses spray-on radiant barrier paint on the underside of your roof
              decking:
              http://tomsangle.com/docs/Radiant.pdf
              So far as I can tell, Tom agrees that foil based roof decking is
              superior for new construction. I believe stapling foil type material
              to the rafters, will provide superior performance but it might be so
              much extra labor that costs outweigh the benefits.

              You might find the following article from the Florida Solar Energy
              Center (FSEC) interesting. All that I have seen from FSEC appears high
              quality practical research, in my opinion:
              http://www.fsec.ucf.edu/bldg/pubs/pf337/

              I must say that I am a total amateur and am merely passing along
              things I have been taught which sound right. Am thinking about putting
              up foil type radiant barrier in my house but have not done the project
              yet. Am somewhat thinking about retro-fitting "skin venting" to our
              exterior walls but first must find someone with professional
              credentials who will endorse such a project. If anyone finds fault
              with what I have said, it will be to everybody's benefit to correct
              me.

              Thanks and good luck -- Mark J.
               
               
               
               

              --- In hreg@yahoogroups.com, "Roxanne Boyer" <rox1@a...> wrote:
              > I am looking for ways to reduce the cooling energy costs of my home.
              I have heard about radiant heat barriers in the form of:
              > 1) Exterior coatings (put on the paint or shingles) that reflect
              solar radiation.
              > 2) Foils that are applied to the underside of the roofing board -
              either sprayed or stapped in sheets - that reflect infared radiation.
              > 3) Foils that cover the attic floor on top of the insulation that
              also reflect infared radiation.
              >
              > Does anyone have any experience with these applications?  Do they
              work?  How much does it cost to have them installed?
              >
              > Theoretically the radiant barrier on the exterior of the roof and
              the radiant barrier on the attic floor should work.  I don't see how
              the foil/spray on the bottom of the roof could work.
              >
              > Chris Boyer
              > "Conservation is a great alternative fuel."
               

              Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


              Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


              Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
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