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  1. #1
    Join Date
    Jul 2019
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    CA
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    Default Radiant Barrier Failing - Any ideas?

    I inspected a home yesterday that I am actually considering purchasing for myself. In the attic, I can see a silver radiant barrier on an exterior wall, that is clearing failing. See the pictures, but it almost looks as if it has bubbled or melted. This exterior wall is stucco, and it appears the radiant barrier was installed first during original construction as it is on the outside of the framing. I haven't seen a radiant barrier visible in any attic around this area before. House in Northern California. Outdoor air temps can get up to 100 in the summer. The roof has some leaks which has caused mold in one of the bedrooms, but no smell of such in the attic.

    Any guesses as to why this is failing? Could this indicate water intrusion through the stucco?

    Would you think that the radiant barrier is used throughout the home, or would it have only been used within the attic areas? Is this something that needs to be corrected, or just live with it?



    Due to a lot of blown in insulation above the framing, I elected not to try and navigate my way to the wall, but may need to.

    Any guesses or suggestions will be helpful!

    John

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  2. #2
    Join Date
    Mar 2007
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    Fletcher, NC
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    Default Re: Radiant Barrier Failing - Any ideas?

    A couple of questions:

    How does a cable of any type (even if low voltage?) get BETWEEN the top of a truss top chord and the roof sheathing when the roof sheathing is nailed tight to the top chord?

    I know, I know, because the sheathing is not nailed tight, but that's not the real question I'm asking.

    Also, in that same photo, all those yellow spots - are they pine sap which has oozed out, or is that from an infestation of beetles?

    The issues with the radiant barrier material on the gable wall seem to be aligned with the gable end truss 'studs' and webs, which is where the sheathing (if any was used) and the lath would be attached to the gable end truss, so I'm guessing possible water intrusion through the stucco at the lath fasteners, and possibly if no sheathing was used (some areas still do not use sheathing over framing).

    It is also possible that the radiant barrier was being used as the drainage plane behind the stucco (which would not be good as it was not designed or intended for that use, and also not good as that would indicate a proper drainage plane was not installed - you wouldn't see the drainage plane as it would be on the outside of the radiant barrier).

    Either way, it that is the drainage plane or if there is a drainage plane outside of it, if ... IF ... if that is from water/moisture getting through the stucco, that water will (it is intended to) weep down by gravity to the bottom of the wall and out a foundation weep screed (oh, wait, that foundation weep screed is likely not installed either, at least from my experience).

    That would imply that the water/moisture penetrating through the stucco on the gable end and below is going down that wall ... which I believe you indicated was where a bedroom was, and that the bedroom had a moldy smell, but not the attic, which could be because no water is getting into the attic, just into the wall below ... the wall at the bedroom.

    Just pondering what I see, or may be seeing, in the photos.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  3. #3
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    Jul 2019
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    CA
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    Default Re: Radiant Barrier Failing - Any ideas?

    Very good observations Jerry. I hadn't even noticed that wire, being too confused by the radiant barrier.

    Zooming in and lightening my image more (attached), I can see what appears to be a ripped piece of the barrier (perhaps from deterioration, or a previous inspection from someone else).

    The picture isn't high quality, but it seems as if there may be black building paper on the outside of the foil layer. Past that, it does not look like sheathing to me, so I suppose it is possible that the stucco was installed (at least in this section) without sheathing.

    I wonder if sheathing would have been used once it hit the wall below, making only the gable areas without sheathing.

    For what it's worth, the obvious moldy areas are not on this exterior wall, and are under roof valleys that I am sure are leaking.

    That doesn't mean there isn't also some issues elsewhere.

    Is it possible the foil is just failing absent any water intrusion? I am trying not to scare myself away from this house if it could be something minor, but don't want to buy into a money pit. I've been in a hundred attics in this area, and this is the first time seeing this foil stuff.
    Is this something you would tear the stucco wall apart to fix if you were buying this house?

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  4. #4
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    Mar 2007
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    Santa Rosa, CA
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    Default Re: Radiant Barrier Failing - Any ideas?

    "Northern California" is a rather large area.

    JP,

    Out here, most trusses are douglas fir. Lots of sap can weep out of that stuff. I would guess sap over anything else, but would need to touch it to be sure.

    John,

    How old is the home? The only times I see yellow fiberglass insulation in my area are homes that are older than 30 years (possibly older). In more current homes, the roof sheathing is OSB with an attached radiant barrier (which is often used on the gable-ends as well), but I don't believe these were around in the '80s. Given my guess on the age, would it be safe to presume there is no radiant barrier on the roof sheathing?

    If the radiant barrier is a part of the sheathing, then the wrinkles might indicate decayed sheathing (drainage plane). If there is no sheathing, then I would share Jerry's concern about the drainage plane.

    I hate to say this, but might be a good idea to put on the Tyvek and head over there to take a close look.

    Did you get a home inspection or are you inspecting yourself? (CA says no-no to conflict of interest. Not that I'm going to turn you in.)

    Department of Redundancy Department
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  5. #5
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    Mar 2007
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    Fletcher, NC
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    Default Re: Radiant Barrier Failing - Any ideas?

    Quote Originally Posted by John Lewiston View Post
    Zooming in and lightening my image more (attached), I can see what appears to be a ripped piece of the barrier (perhaps from deterioration, or a previous inspection from someone else).
    That looks too 'flat' and 'stiff' to be a piece of radiant barrier (see the pieces of radiant barrier laying around it), and if you zoom in on the hole, it looks like some type of something (sheathing?), fiberboard, foam insulation, ??? around the edges of the hole. If that light colored piece laying on the insulation is from that hole, then you may be looking at: a) the back of building paper (15# or 30# felt) or the back of paper backed lath (the paper of paper backed lath is there to serve as a bond breaker to keep the stucco from adhering to the drainage plane behind the paper backed lath - for decades, many people in many places thought they could apply paper backed lath over wood sheathing and it was okay, except that they missed the drainage plane, which lead to wood sheathing rotting out behind everything because it got wet and stayed wet.

    The picture isn't high quality, but it seems as if there may be black building paper on the outside of the foil layer. Past that, it does not look like sheathing to me, so I suppose it is possible that the stucco was installed (at least in this section) without sheathing.
    You need to get to that area an have a good, up close, look at what is there and what was there (the piece laying on the insulation).

    Is it possible the foil is just failing absent any water intrusion? I am trying not to scare myself away from this house if it could be something minor, but don't want to buy into a money pit. I've been in a hundred attics in this area, and this is the first time seeing this foil stuff.
    Is this something you would tear the stucco wall apart to fix if you were buying this house?
    You won't know if the stucco wall needs to be torn apart for a proper look from the outside until you get a good close up look from the inside.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  6. #6
    Join Date
    Jul 2019
    Location
    CA
    Posts
    3

    Default Re: Radiant Barrier Failing - Any ideas?

    Quote Originally Posted by Gunnar Alquist View Post
    "
    John,

    How old is the home? The only times I see yellow fiberglass insulation in my area are homes that are older than 30 years (possibly older). In more current homes, the roof sheathing is OSB with an attached radiant barrier (which is often used on the gable-ends as well), but I don't believe these were around in the '80s. Given my guess on the age, would it be safe to presume there is no radiant barrier on the roof sheathing?
    The home was built in 1995.

    The roof sheathing has no radiant barrier, at least on the attic side.

    The yellow blown in insulation was a bit odd just in its texture. Didn?t seem as fluffy as the pink stuff I normally see. I wasn?t sure if that was typical of the yellow, or if it could indicate a past or ongoing humidity issue adding moisture and compressing down the insulation.

    The house is bank owned and very neglected, so trying to sort out all of the issues I can find to make sure the numbers still work. I have to decide tomorrow morning to continue with the purchase or not.

    I will try to crawl over to that area this evening and update the post if I am able to.

    John


  7. #7
    Join Date
    Oct 2010
    Location
    MONTREAL QUEBEC-CANADA
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    2,075

    Default Re: Radiant Barrier Failing - Any ideas?

    John, is that the gable end of an attic?

    Behind the barrier appears to be Tentest asphalt impregnated organic mulch board.
    If so, you agree to the above, my questioning/reasoning would be; A: Why the reflective/radiant barrier is there in the first place?
    B: Is this a cold climate?
    C: Is the attic a vault or vented? Volt? Gess Louise! Damn, must have electrical on my mind.

    As for cause of damage. I report defects/deficiencies and not the cause.

    Last edited by ROBERT YOUNG; 07-17-2019 at 04:25 AM.
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