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Re: [hreg] Re: Radiant Heat Shield

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  • Peter
    Mark, I came across skin venting in 1992 when I took a home building class at HCC. The concept was intriguing because with very little effort natural air
    Message 1 of 11 , Feb 6, 2003
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      Mark, I came across "skin venting" in 1992 when I took a home building class at HCC.
      The concept was intriguing because with very little effort natural air movement
      can be used to reduce temperature and moisture in confined spaces.
      You are correct, I would not use this technique in areas where climate can get
      very cold for long periods of time, but in houston or similar area the climate
      is supportive of this technique.
      As to retrofitting, if you have vertical sidings it may be possible you already have
      a continuous airspace behind your sidings which can be utilized by cutting
      vent openings into the bottom of the sidings. The next problem is where your siding
      meets the roof eves, this may not be so simple since existing construction may have
      2x4's blocking the continuous airflow to the attic. So in summary, for existing homes
      you may not be able to retrofit due to built-in blockages which will not allow a continuous
      opening into the attic.
      I am adding a reference for pictorial schematic, please note i am not endorsing
      the product at this site but the full chapter makes for good reading.
      http://www.rima.net/handbook/page8.htm#walls
      http://edis.ifas.ufl.edu/BODY_EH244
      By the way I forgot to tell you that you can mate vent skin construction with
      attaching a radiant barrier in the wall ... just another way to keep the radient heat
      out of your house.
      If you are planning to have a contractor install "vent skinning" techniques be prepared
      for a lot of hand-holding and insisting on your way  " it needs to be done" with your contractor.
      The most common talk-back I received was "we have never done it this way" and
      "it can't possibly work" :(  .. so stick to your guns !!!!!!!

      By the way I have been very pleased as to what these additions did to the electricity
      consumption.
      peter


      mark r. johnson wrote:
      --- In hreg@yahoogroups.com, Peter <peterk1@s...> wrote:
        
      ...vent skin contruction : This means that outside walls have vents 
      built into the bottom
           of the wall and a continous airspace behind the wall from
          
      bottom 
        
      outside wall vents to
           roof  overhang. The area where the outside wall meets the roof 
      overhang can be engineered
           so that wall venting exhausts into the attic and then venting
          
      exits 
        
      through the continuous
           hip/ridge vents. The concept utilizes the physical property of
          
      hot 
        
      air always rising ... you can really
           feel the draft of air coming into your attic from between the 
      walls. This concept prevents heat
           build up in the outside walls and helps with the air draft in
          
      the 
        
      attic .. again preventing heat
           build up.
          
      Peter, I have heard about "vent skin" construction (sometimes called
      "skin vent") via Brian Parffey's six-week "Builder's Academy"
      workshop, also from his one-time mentor Tom Tynan, and also from
      architect LaVerne Williams. 
      
      I am intrigued because 
      1) some of them endorse it so emphatically, and 
      2) there have only been a few places in printed literature that
      support this method.
      
      Parffey tells us this is a method usable largely because it doesn't
      get very cold in winter in our area, and somewhere between here and
      Dallas the winters get strong enough that vent skin construction is
      not advisable. So this is identified as a very regional construction
      method, which explains why it may be unknown outside of our hot-humid
      region.
      
      Tynan endorses this construction method, I believe he advocates it but
      does not hammer on it being a necessity as Parffey does. For what it's
      worth, I have seen in Williams' published articles a very early
      reference to skin venting in the 1970's, the earliest I am aware of.
      
      I would like to ask you, are you describing a method which must be
      used with original construction? If not, can you say a little bit
      about retro-fitting this ventilation to an existing building. Surely
      there must be some pros and cons. Any new references to printed
      literature about this method, or references to someone who can give me
      expert advice, would be most welcome.
      
      Best wishes -- Mark J.
      
      
       
      
      Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
      
      
        

    • 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 2 of 11 , Feb 6, 2003
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        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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      • 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 3 of 11 , Feb 6, 2003
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          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 4 of 11 , Feb 9, 2003
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            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 5 of 11 , Feb 9, 2003
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              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 6 of 11 , Feb 9, 2003
              • 0 Attachment
                -----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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