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Community and Q&A

Fiber cement siding over furring strips

hughsdb | Posted in Green Building Techniques on

In our region, which gets an average of 37″ of rain annually, most folks put fiber cement siding against House wrap on OSB. Though there have been some projects we have seen that put the siding directly to the framing with no sheathing. In short order this is quite apparent because of the noticeable wave in the siding. We would like to start using furring strips on top of well sealed foam sheathing to create a drain pan. But we are afraid of the wave. We do quite a few resides and are typically dealing with 16″ OC framing. When we are building new or doing additions, we use advanced, 24″ OC framing. Are you folks who are using furring strips getting the wave, especially on 24″ framing?

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  1. GBA Editor
    Martin Holladay | | #1


    I'll let other GBA readers comment on the "wave" problem.

    Hardie instructions permit the installation of their products on framing that is spaced 24 inches on center. The company also provides instructions for installations over furring strips.

    Here are links to two relevant documents:

    HardiePlank Lap Siding installation instructions

    Applying James Hardie Siding over Continuous Insulation and Non-Nailable Substrates

  2. hughsdb | | #2

    Thanks Martin. I had not seen the second document before. But, I'm left still worrying about the wave. I mean siding with a wave will still function. It is primarily an aesthetic thing that Hardie may not be worried about. Have other people using this method had an issue? Maybe it is solved by a certain width of furring strip. Also, we are probably going to rip plywood for the strips. I think that Hardie will allow their siding to be attached to 7/16 sheathing, which seems a bit iffy to us. What thickness of furring strips are others using? Left to our own devices we would probably use 3/4" but if 5/8 does the trick that would save a little $. Thanks.

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