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Thread: Cellulose

  1. #1
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    Cellulose

    I am not sure that this is the correct audiance - please let me know if i am posting incorrectly.

    I guess this question leads to a years old debate - is cellulose a good product for insultation. I like it, and feel that at the time of install its a good product. I am also aware that some people dislike it, some people love it from all my reading... I do believe its a safe material (Whether i am right or wrong...)

    My main questions are - Over a period of time - say 30 years, does it deterioate and turn to dust and loose its value?

    Also - when dense packed is blown into the walls, does it settle over time.. by this i mean in 5 years time - if I took of some Rock.. would the top 6 inches of the wall be without insulation?



    Thanks everyone

  2. #2
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    For the $$$$ is the best !!!!

    [quote=doogan123;1951644]I am not sure that this is the correct audiance - please let me know if i am posting incorrectly.

    Yes, the insulation has the biggest impact on HVAC.. Period !!


    I guess this question leads to a years old debate - is cellulose a good product for insultation. I like it, and feel that at the time of install its a good product. I am also aware that some people dislike it, some people love it from all my reading...

    Its the American way... if your a winner.... your hated !!!!
    Its Better, Healthier, E-Friendly, Non-Toxic, Affordable, Safer, !!!!


    My main questions are - Over a period of time - say 30 years, does it deterioate and turn to dust and loose its value?

    If in a nasty, hot, moist attic.. yes it can deteriorate.... all materials exposed to extreme temps and extreme moisture changes deteriorates !!

    Also - when dense packed is blown into the walls, does it settle over time.. by this i mean in 5 years time - if I took of some Rock.. would the top 6 inches of the wall be without insulation?

    DO NOT DENSE PACK !!!! Spray "Stabilize Cellulose" it has an adhesive in it sets up like papermesha..
    Plus the boric acid inhibits pest, fire, and mold !!!
    30% to 50% better than batts thermally and infiltration as well !!!
    If they do not know how to damp spray.... they don't need ot be in the industry!!!
    YES... Dense packed walls with any loose fill WILL SETTLE !!!!

    go to my page www.kesspray.com for tons of info....

  3. #3
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    Richmond, Virginia
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    Should blown cellulose depth in attic cover flex ducts?

    [QUOTE=kenny mac;1951659]
    Quote Originally Posted by doogan123 View Post
    I am not sure that this is the correct audiance - please let me know if i am posting incorrectly.

    Yes, the insulation has the biggest impact on HVAC.. Period !!


    I guess this question leads to a years old debate - is cellulose a good product for insultation. I like it, and feel that at the time of install its a good product. I am also aware that some people dislike it, some people love it from all my reading...

    Its the American way... if your a winner.... your hated !!!!
    Its Better, Healthier, E-Friendly, Non-Toxic, Affordable, Safer, !!!!


    My main questions are - Over a period of time - say 30 years, does it deterioate and turn to dust and loose its value?

    If in a nasty, hot, moist attic.. yes it can deteriorate.... all materials exposed to extreme temps and extreme moisture changes deteriorates !!

    Also - when dense packed is blown into the walls, does it settle over time.. by this i mean in 5 years time - if I took of some Rock.. would the top 6 inches of the wall be without insulation?

    DO NOT DENSE PACK !!!! Spray "Stabilize Cellulose" it has an adhesive in it sets up like papermesha..
    Plus the boric acid inhibits pest, fire, and mold !!!
    30% to 50% better than batts thermally and infiltration as well !!!
    If they do not know how to damp spray.... they don't need ot be in the industry!!!
    YES... Dense packed walls with any loose fill WILL SETTLE !!!!

    go to my page www.kesspray.com for tons of info....

    KM ....is it a bad idea to cover attic flex ducts with blown cellulose? Will that cause unwanted condensation? How do I get around this issue if I want to add insulation? Thanks ....

  4. #4
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    It should not be covered nor should it lay on the insulation; in addition the flexes should not lay on each other. It should be supported every ten feet with a minimun of sag.

  5. #5
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    I hope this helps... this is some R&D I was involved in about buried ducts

    [quote=VA GENT;1951667]
    Quote Originally Posted by kenny mac View Post


    KM ....is it a bad idea to cover attic flex ducts with blown cellulose? Will that cause unwanted condensation? How do I get around this issue if I want to add insulation? Thanks ....
    Sorry "adrianf" buried ducts is recommended in the Title 24 Calf. Energy Code.
    I was part of the HoBo Data gathering and actually done the work on this.

    If ya can't put them in the house.... them drop them and cover them ~~~

    CARB Is Evaluating Duct Insulation Strategies

    May 2003



    Thermograph of heat flow around a cooling supply duct in a hot attic.
    A key element of many Building America projects has been to reduce duct losses or gains using affordable methods. To this end, the Consortium for Advanced Residential Buildings (CARB) has been researching the energy benefits and implementation issues associated with burying ducts under low cost loose fill attic insulation.
    Through improved duct sealing practices developed in recent years, many HVAC contractors are now capable of reducing duct leakage to close to 5% percent of air-handler flow. With duct leakage now under control in many cases, conductive energy losses have become a more significant component of thermal distribution inefficiency than ever before. Placing ducts under loose-fill attic insulation reduces conductive heat gains in the summer and heat loss during the winter at no additional cost. The greatest benefit associated with increased duct R-values is a reduction in peak cooling demand when attic temperatures are hottest. This peak load reduction can even result in cooling equipment downsizing of � ton and thus a net decrease in first cost. Because a tight duct system buried under enough attic insulation can approach the energy performance of a duct system located in conditioned space at a fraction of the incremental cost, it is an attractive alternative for cost conscious builders.
    But how much attic insulation is enough? To begin to answer this question and to obtain a more quantitative understanding of the construction variables that affect the performance of buried duct systems, CARB conducted a heat transfer modeling analyses using ALGOR� software. As a result of this work, an equivalent R-value that conventional hung ducts must be wrapped with to achieve the same thermal performance as buried ducts was determined for a variety of buried duct configurations. CARB looked at small ducts and large ducts, run over or between truss chords in attics with different levels of blown-in fiberglass and cellulose.
    As a result of this study, design guidelines for predicting the performance of buried ducts were developed. These guidelines assign an equivalent R-value to a duct based upon its classification as either "deeply buried," "fully buried," or "partially buried." The advantage of these designations is that they are both easy to understand and verify. Because field validation of modeling results is still required, the equivalent R-values chosen are somewhat conservative. A duct system equivalent R-value is then calculated based upon the different equivalent R-values of component trunks and branches.
    Applying this method to different duct layouts demonstrates the effect that a more compact duct system design has on increasing duct system equivalent R-value. With a well-engineered duct system layout and R-38 of attic insulation, our modeling-based guidelines indicate that equivalent system R-values of R-15 are achievable. Coincidentally, there is typically no further equipment downsizing potential at system R-values greater than R-15.
    Recently in response to this work, the California Energy Commission (CEC) has become interested in including a buried duct credit in their state energy code. At their request, CARB has developed language concerning the design and field verification of buried duct systems that is in the process of being adopted into the 2005 California Energy Code. (For more information, see: (PDF 151 KB) Download Acrobat Reader.
    In addition to this ongoing work with the CEC, CARB is planning field-testing of buried duct systems this summer to validate/refine modeling results. This approach is not currently recommended for use in hot-humid climates.

  6. #6
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    KM

    You're dangerous, if you come to my neck of the woods and you blow fiberglass or your beloved cellulose insulation over the the duct work here you will have condensation and mold in rapid fashion.

    Quoted from:Craig DeWitt, principal of RLC Engineering, LLC, Clemson, S.C published in ACHR News Dec 12, 2003

    “If we have ducts in contact with insulation, we have more of a potential for condensation,” he added. “If you’ve got insulation blown around ducts, you’re asking for trouble.”
    Last edited by adrianf; 08-06-2008 at 02:00 PM.

  7. #7
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    4H: Hot, Humid Houston H.O.
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    Maybe California can get away with that. Does any part of their jurisdiction have high dewpoint weather? Of course Florida lives with 70-75 dewpoint much of the year.

    Regards -- Pstu

  8. #8
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    Houston isn't all that far behind us.

  9. #9
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    Richmond, Virginia
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    Richmond, VA has its hot & humid summers where dew point ranges from mid 60's to 70.
    Not being in Florida or Houston, should I be concerned about adding more cellulose which will completely cover the partially buried flex ducts?

    Thanks....
    Last edited by VA GENT; 08-06-2008 at 02:50 PM. Reason: incorrect dew point info

  10. #10
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    WOA..... So your say the sheet rock below sweat ???

    Quote Originally Posted by adrianf View Post
    KM

    You're dangerous, if you come to my neck of the woods and you blow fiberglass or your beloved cellulose insulation over the the duct work here you will have condensation and mold in rapid fashion.

    Quoted from:Craig DeWitt, principal of RLC Engineering, LLC, Clemson, S.C published in ACHR News Dec 12, 2003

    “If we have ducts in contact with insulation, we have more of a potential for condensation,” he added. “If you’ve got insulation blown around ducts, you’re asking for trouble.”
    What is insulation for than anyway.... ?????

    So your saying it is best to suspend a R-6 (R-8 now) full of 45* to 55* air in 150* 90% RH ambient air with a slick surface
    Over that same duct buried below insulation where it should be with in 5* to 10* of the interior air

    Roll one out of your bag !!!! Thats some good stuff !!!!!

    With you guys thinking.... Way do they even bother putting insulation on flex at all..... ????????????

    We buried those ducts just North of Atlanta.... During the R&D

    Your saying as well all the top "Building Forensic Scientist" are "Dangerous.

    Let me remind you !!! All the R&D I have been involved with since 1998 has had a direct impact on everybody's building codes...

    Sorry I will have to check on this DeWhit guy....

    I know last time you guys trashed me.... I found out your info was from some idiot who was paid of by the "Fiberglass Crooks"

    Let me check this Dwhitt guy out

  11. #11
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    Doesn't the last line of the quoted article state "This approach is not currently recommended for use in hot-humid climates. "?

  12. #12
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    Not Currently back in 2003...

    Quote Originally Posted by Remodeltdt01 View Post
    Doesn't the last line of the quoted article state "This approach is not currently recommended for use in hot-humid climates. "?
    Not currently in 2003... here is Craig DeWhit "Quote"

    COLUMBIA, S.C. — Many building codes in the southeastern United States call for increased attic and crawl space ventilation to fight moisture and related IAQ problems. Craig DeWitt, Ph.D., P.E., challenged that notion at the South Carolina Association of Heating and Air Conditioning Contractors’ (SCAHACC’s) 2003 Indoor Comfort Science Conference.DeWitt, principal of RLC Engineering, LLC, Clemson, S.C., pointed out that in more humid climates, venting the attic and crawl space could spell disaster. “Code says to vent the heck out of them,” De Witt said. “If that doesn’t work, vent some more. However, once we get condensation in ductwork, it is self-propagating.”
    In a paper he authored, DeWitt re-counted, “At an Affordable Comfort meeting that I recently attended, a speaker from Canada said that venting crawl spaces in the southeastern U.S. was lunacy. I have to agree.”
    His argument is based on psychrometrics.
    “Mold is a symptom of a moisture issue,” DeWitt explained. “It takes moisture to have fungus.” Symptoms of moisture include fungi (mold, decay), condensation, and wood changes.
    “Mold is everywhere,” he pointed out. “We can’t make spaces sterile environments. The spores are already there.” By addressing condensation moisture, however, HVAC contractors address “the one [element] we can control.” There’s no need to become overly concerned, say, if the only evidence of moisture is a little condensation on the windows. “I don’t see any reason to call in a Haz Mat team.”
    In order to understand how ventilation can lead to moisture problems, DeWitt said contractors should understand a few rules:
    Water changes phase at room temperature, from liquid to vapor.“Psychrometrics are the thermodynamics of just plain old air,” he explained. Relative humidity (rh) equals the amount of water over the capacity of water the air can hold. Mathematically,
    rh = amount of H2O/H2O capacity
    The dewpoint is the temperature at which the amount of H2O = H2O capacity (capacity of the air to hold water). Below this temperature, condensation forms.
    According to DeWitt, “From a psychrometric standpoint, venting a crawl space to remove moisture works when the outside air is drier than the crawl space air. ‘Drier’ does not mean a lower relative humidity, but rather a lower absolute humidity. Relative humidity is a ratio of the amount of moisture in the air relative to the amount the air can hold at that temperature. Absolute humidity is the amount of moisture in an amount of air.
    “Air at 85 degrees F and 60 percent rh has the same absolute humidity as air at 70 degrees and 100 percent rh. So venting a 70 degrees/100 percent rh crawl space with 85 degrees/60 percent rh air will not remove moisture.”
    DeWitt explained that the dewpoint temperature is the temperature at which condensation forms as air is cooled. “At the dewpoint temperature, the air is saturated and any further cooling will result in condensation. In the above example, both the 70 degrees/100 percent rh crawl space air and the 85 degrees/60 percent rh outside air have the same dewpoint temperature: 70 degrees. If we vent a crawl space with air that has a higher dewpoint temperature than the crawl space air, we will actually be adding moisture to the crawl space rather than removing it.”
    To have condensation, you need moist air and a cold surface. Keep in mind that “moist,” “cool,” and “cold” are all relative.
    So, let’s say the supply air is 55 degrees, there is some condensation on the coils, and the ducts are uninsulated. Attic conditions are 80 percent rh, 80 degrees on a sunny day; the dewpoint temperature is 75 degrees. Any bare duct will get condensation on it.



    Getting MAD

    “If we vent a crawl space with air that has a higher dewpoint temperature than the crawl space air, we will actually be adding moisture to the crawl space rather than removing it,” is the message Craig DeWitt gave to SCAHACC contractors.


    In addition to understanding the fundamentals of psychrometrics, DeWitt pointed out that HVAC contractors need to know something about the moisture and air dynamics (MAD) of wood, especially in crawl spaces and attics. Certain wood conditions can indicate moisture problems, even though moisture might not be present when the contractor is inspecting the system.Sweating ducts in the crawl space, for example, can create a cupping problem in wood floors directly above. Bowing can occur during the heating season.
    Moreover, fungi “like to eat biological things” such as wood, he said. Mold and mildew need 80 percent rh or higher on a surface, where they grow. Decay fungi, erroneously called dry rot, needs liquid water. “There is no such thing as dry rot,” De Witt said. “It’s the result of a wet decay.” By the time the damage is discovered, the fungi have used up whatever moisture there was.
    A sweating duct in contact with wood beams and thermal insulation can lead to these problems. The damage can still be visible even though the duct may not be sweating when the contractor sees it.
    To get condensation on a surface, DeWitt reiterated, the surface temperature has to be lower than the dewpoint temperature of the air.



    or more info, click here
    Let’s say you’re in a crawl space with a 78 degrees ambient temperature, 90 percent rh; you need about a 3 degree temperature drop to go to 100 percent rh. “If we start seeing 90 percent rh any place, we are very close to having a disastrous situation,” DeWitt said. With insulation, the duct surface temperature is 74.2 degrees (60 degree air inside the duct). The dewpoint temperature is 74.5 degrees; that duct will not sweat.Now let’s say the air being moved is 50 degrees and the duct surface temperature is 74 degrees. That duct will sweat. You might think that higher temperatures in the attic would prevent duct sweating; the ambient summer temperature there is 130 degrees during the day, with a dewpoint of 74 degrees. At first glance it looks pretty good, but “there is a flipside,” said DeWitt. “It does get cool at night.” Temperatures in the attic can drop to 75 degrees at night, and the surface duct temperature drops to 72 degrees. With the 74 degree dewpoint temperature, the result is condensation.
    At 90 percent to 100 percent rh, if the temperature is dropped about 3 degrees, you add 16 grains of moisture per pound of air, he said. Therefore:
    A 1,500-foot crawl space that’s 3 feet tall = 4,500 cubic feet

  13. #13
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    Guys I searched my tale off !!

    The only negative comments I could find about buried ducts was some you have to pay for access....

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