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  1. #40
    Join Date
    Nov 2003
    Location
    northern mass
    Posts
    411
    I've mentioned this before, but I work for the best contractors around and in the nicest homes around. The area I work in demands nothing but the best...and they are willing to pay for it. It's kind of a "I don't care about the cost....will it work ?" attitude.

    Almost every home I work in is sprayed.


    Everywhere.


    And yes, they often spay my ducts as well ...area permitting.

    I have to use HRV's in these homes because of their tightness....but also smaller equipment.

    I like the HRV fact because I can now control all the air in my home as I see fit....be it the air system,venting,and now even the air coming in.

    These homes are QUITE comfortable. I probably can't describe the difference to you on a computer, but to walk into one of these homes I work in....you can just feel the difference.

    Sounds like a comercial 'huh ? hahahaa

    They are also all radiant heat as well. Foam helps.


    My two cents.

  2. #41
    Join Date
    Jun 2004
    Location
    Dallas
    Posts
    179
    IT may be expensive to have put in, but in a new home quite a bit of that can be recouped instantly by the smaller HVAC system requirements. The rest is recouped relatively quickly by the obvious result of big-time energy savings.

    If you are building a new house in a non-mild climate- it is an absolute MUST. I am surprised it is not code for larger houses in some areas.

    My brother in law was quoted 3 systems for his new 2 story house for a total of 7.5 tons.

    When they recalculated using Icynene, he went down to 2 systems and 4.5 tons.

    Cut his HVAC costs by almost 8k.

  3. #42
    So,as a novice I'm wondering why not build with SIPs or is that what you guys are talking about?

  4. #43
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    have you with foamed attics in your area had a chance to view the foam after a few years, looking for shrinkage?

    ALL insulation equates to entrapment of air in small pockets. If water replaces the air, the heat transfer is EXCELLENT!

    will the water based foam be destroyed by driving rain for many hours?

  5. #44
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    have you with foamed attics in your area had a chance to view the foam after a few years, looking for shrinkage? I note the article by Ntl Roofers stated the foam layer had shrinkage & bowing problems; they suggest that these problems will not be limited to such insulations under single ply membrane (which is common now for large area flat roofs).

    ALL insulation equates to entrapment of air in small pockets. If water replaces the air, the heat transfer is EXCELLENT!

    will the water based foam be destroyed by driving rain for many hours?

    the necessity for insulating having a fire rating for ducts which are several feet from the heat source should be slight -- if fire travels through 8- 10ft of duct, it should be obvious the structure adjacent to the actual heating device will be on fire.

    [Edited by cem-bsee on 08-24-2005 at 08:39 AM]

  6. #45
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    SIPS

    >>So,as a novice I'm wondering why not build with SIPs
    >>or is that what you guys are talking about?

    SIPS are an interesting subject in building science, but I think it deserves its own thread. Worth noting are a tabulation of its extra costs, all the other trades which will charge more for the unfamiliarity of working with SIPS. Of course a plus is the superb insulation and airtightness of that building material.

    I am sort of a technophile but can easily entertain the idea that maximizing craftsmanship with conventional building methods, can deliver more or less equal results. I could take either side if it were a debate. If you care to initiate a new thread, there certainly will be HVAC implications and I can point you to some research on the subject (which a dedicated Google searcher could certainly find on his own, admittedly).

    Best wishes -- P.Student

  7. #46
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,415
    I've done reading on the water leak issue. Icynene was recommended because it is open pore and will pass any roof leaks, which would be quickly discovered and repaired.
    Urethane is closed cell and would hold water against the sheathing, or leak it out some distance from the real leak.
    Col 3:23


    questions asked, answers received, ignorance abated

  8. #47
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    just visited ICYNENE.com: a vapor barrier is needed, does not shrink, is not infiltrated w/moisture laden air, perms= 10 for 5" thick, R=3.6/inch tk, limited lifetime warranty --

    seems to have been around since 2001 -- so, not much info about shrinkage after 10y!

    R=5/inch for Styrofoam, which has been around for 50y. I have seen it used since 1960, esp for insulating under perimeters of slabs. I have used it for my houses since 1970.

    seems like roof leak water would not go thru Icynene, with a vapor barrier in place, and air can not go thru -- ??

  9. #48
    Greetings all. We've come a long way since I started this thread in June. Last Friday they finished the closed cell foam on our roof. We went with 3" and I have high hopes. A 30 pint dehumidifier has been running temporarily in the attic since they finished.

    I can tell you that the Relative Humidity in the attic has steadily declined. It began at 69% RH and 79 degree dew point last Friday. As of tonight, 6 days later, it has trended down to the amazing reading of 46.3% RH and 64.1 dew point. I am using low tech wet bulb dry bulb temps and a very cool psychrometer calcultor site: http://www.connel.net/freeware/psychart.shtml

    I am meeting with the HVAC contractor tomorrow to discuss replacing the supply ducts as the insulation is soaked from before and we feel new insulation will definitely protect a 15 or 20 degree differential (duct temp to dew point)to prevent condensation.

    Plan C is an Ultra-Aire dehumidifier 135H. I will keep you posted with results. The sad part is we have to do this all over again for the the first floor unit, which has sweating ducts in the garage ceiling. And I thought I was going to relax when I retired. Yeah, right.

  10. #49
    Join Date
    Mar 2005
    Location
    Near Philly
    Posts
    98
    Read:
    http://www.asphaltroofing.org/pdf/tb_211.pdf
    Looks like not a good idea from the shingle perspective.

  11. #50
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    Asphalt shingles

    On the plus side, FSEC has some research on the recommended type of roof construction, and the added air space makes it highly energy efficient in a hot climate. One should expect only good results performance-wise following their instructions.

    The cost would be elevated some due to the extra layer of plywood on the roof, if I read the instructions right. I don't have the experience to put this into perspective.

    On the negative side, why are we going to any lengths to protect asphalt shingles in the first place? Despite the "guarantees", such a roof in S.Texas would be expected to need replacement after 15 years. Often a hailstorm damages a roof and some insurance company pays to replace it before the shingles die of old age. So what if your "40 year" shingles might fail warranty, you might get a free bundle of replacement shingles if your ducks are all in a row -- it is my impression that is puny in comparison to the labor costs. According to Lstiburek the additional stress provided by roof-level insulation, might decrease shingle life 1-2 years, not more.

    Lstiburek has pointedly stated that asphalt shingle makers have never published what temperature range *is* rated safe for their product. He strongly implies that in normal service in certain hot states, roof temperature would exceed any temp rating the makers would be likely to endorse. So the shingle companies are in the awkward position of 1) telling you some temperatures are "too hot" for their product to last, and 2) being silent as to what temperatures are safe.

    Still, asphalt shingles are the inexpensive choice compared to any real alternatives. The whole world uses them because you can buy several shingle roofs for the price of one of another material. So what are you gonna do? Probably accept the shortcomings of asphalt shingles like everybody else.

    Regards -- P.Student


  12. #51
    Thanks for the input, but I researched this as thoroughly as possible before foaming. I called Elk, the manufacturer of our shingles, and they have what I will term a "letter of acceptance" to various foam manufacturers. Basically it says the application of that manufacturer's foam has no affect on the Elk warranty. Although Elk agrees the temperature of the shingle is somewhat elevated, they don't consider it a large enough issue to void the warranty.

    I was more concerned about the sheathing, but the humidity and sweating ducts were too overwhelming a problem not to go with the foam. Here at the SC coast the heat and humidity are extremely oppressive.

    Based on monitored temps, relative humidity and dew points in the attic since the foam, I am convinced it was the right thing to do.


  13. #52
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    so, have you wound up with a sealed attic? ie no ventilation openings to the outside?

    My testing at Anaconda Wire & Cable indicated that covering type NM cable with insulation reduced its ampacity!!! -- just as such would for ANY cable or wiring. We concluded that keeping building wire to the outside along the exterior walls would help aleviate this problem. I seem to remember reporting our findings, w/data to UL -- early 1980s.

    since toxic gasses are emitted, mainly CO, I urge you to caulk along all wall to ceiling seams.

    what does the building code state about exposed foam in the attic? As I remember, if insulated crawl spaces have storage of goods, the foam should be covered with 0.375" tk gyp. In fact, Styrofoam states on EVERY sheet that it should be covered with 0.375" gyp.

    BTW, the FAQ section states that Icynene has been used in houses since 1986 -- so about 20y.

    [Edited by cem-bsee on 08-26-2005 at 05:43 PM]

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