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Community and Q&A

Looking for Hardie panel rainscreen experience

jberks | Posted in General Questions on

Dear GBA’ers,

I’m planning on using hardie panels to create a rainscreen system for my cladding as follows:

1/2″ OSB
Tyvek
2″ Roxul comfort board
1×4 strapping at 12″ oc (also the airgap)
5/8″ hardie panels (2’x4′ staggered brick pattern)

I want to just screw the panels right to the strapping, and have open air gaps at the joints. (see example photo)

After speaking to my local Hardie rep, he said they don’t support that because water gets in behind the panels and they will swell, crack or freeze. He is adamant that all ends be flashed and there is no gaps by using easytrim or fry trim systems (to which it wouldn’t be an open rainscreen anymore and I have to focus on venting at tops and bottoms which will be more difficult with this reno)

I’m thinking its a crock of sauerkraut.

Does anyone have any long term experience with installing hardie panels in a rainscreen system?

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Replies

  1. JC72 | | #1

    Hardie is responsible for honoring their warranty so it's entirely up to you. What you're proposing is is "open joint rainscreen cladding" this is different from a typical rain screen which receives occasional wetting. I suppose if all six sides were primed/painted you might be ok, but again that's a call to be made by the panel manufacturer. You also have a potential issue with the warranty of your WRB.

    My two cents.

  2. GBA Editor
    Martin Holladay | | #2

    Jamie,
    A manufacturer is telling you that you will be using their product in an unapproved manner, and you still want to do it.

    Technically, that would be a code violation.

    In any case, it's your house (I assume), and therefore, it's up to you whether you want to throw the warranty out the window.

  3. Expert Member
    ARMANDO COBO | | #3

    We've been doing Hardie Siding over 1x4 rainscreens for years. Hardie REQUIRES a rainscreen in commercial applications, but they do not require it in residential applications (i think they should), and they do cover the warranty. I'm concerned that you installed your rainscreen at 12"o.c., and if your wall studs are at 16"o.c. or 24"o.c., it means that some of your rainscreens are attached to the sheathing. Hardie requires the siding to be attached to the framing.You can always contact their Technical Support number.

  4. GBA Editor
    Martin Holladay | | #4

    Armando and Jamie,
    I'm assuming that the Hardie rep's objections are based on the lack of Z-flashing at the horizontal seams -- not the existence of an air gap and furring strips.

  5. Expert Member
    ARMANDO COBO | | #5

    The Hardie panel siding is installed with XtremeTrim when looking for the modern look, and when we use it with 1x2 battens for the country look. In all cases, the panel boards are primed on all six sides.

  6. SwitchgrassFarmer | | #6

    I think our home would be the Hardie panel "country look" as Armando describes it. However note that we still utilized Z-flashing at the horizontal panel intersections and at the bottom rain screen vent. Top rainscreen vent (Cor-A-Vent) is covered by a frieze board. Snapped some quick pix.

    My worry with too large a gap between Hardie panels isn't the warranty, it's insects. They love any such hiding place particularly when they are looking for winter cover. This time of year every wasp, stink bug and lady bug is hoping to make our house theirs. This is a vulnerability that has been discussed before on GBA. https://www.greenbuildingadvisor.com/community/forum/green-building-techniques/22209/potential-rainscreen-issues

  7. jberks | | #7

    Hi Armando,

    I haven't installed it yet. That photo is an example of what I'm looking to do.

    The 12" spacing is because the studs are spaced at 12" oc, so the purpose of that is to actually get it mounted on the studs.

    When you say you do rainscreens do you mean "open joint rainscreen" or the typical rainscreen (John thank you for the clarification)

    I just spoke to someone who's does the open joint rainscreen with Hardie panels, they installed it 8 years ago and report no problems at all.

    However, the insect thing is REALLY intereeting, and I would have never thought of that! Perhaps that aspect alone will make the extra labour and potential non-venting issues worth doing a traditional rainscreen.

    Thanks all!

    Jamie

  8. Expert Member
    MALCOLM TAYLOR | | #8

    Jamie,
    Open joints on a rain-screen cladding do invite insects, but also allow bulk water to enter the cavity which negates the benefits of ventilation.

  9. ecodude | | #9

    What ever happened with your hardie issue?

  10. ecodude | | #10

    Open rainscreen was/is a part of the past, think living building, natural building, etc…what transpired since this thread started?

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