Advice on Slicker Max rainscreen?
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| Posted in General Questions on
I am looking at a wall comprised of 2×6″ frame, cellulose in the cavities, Huber Zip system exterior, 1.5″ Poly, Slicker Max Rainscreen 10M, and then nailing cedar shingles directly through rainscreen and foam (approx 1 3/4″).
My Builder does not want to deal with putting up 1×4″ nailers every 5″ to hang shingles from, so thinking rain screen will give shingles ability to breath. Depending on cost this might be an alternative.
Also not sure if this will meet code on Cape Cod with wind code, or if hanging shingles in this manner would work. Thanks.
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Replies
Steve,
When you wrote "1.5 inch poly," I assume that you are talking about polyiso.
I have never heard of installing cedar shingles with long nails through 1 3/4 inch of squishy substrate. My guess is that it would probably work, but it's a little risky. You are attempting an untried technique.
The usual solutions in your case are either (a) to install a second layer of OSB on the exterior side of the rigid foam, or (b) to install nailbase instead of polyiso (to provide the second layer of OSB), or (c) to install lots and lots of horizontal 1x3 or 1x4 furring strips, or (d) to use a different type of siding with vertical furring strips.
With my own house (built several decades ago), I went with option (c). It worked.
Thank you Martin!
Steve,
Huber has a Zip R product that you could use that would put 1.5" polyiso insulation behind the Zip panel, so your nailbase would be 1.5" closer to the shingles. For your location you may need to consider this note from Huber: "any structure located in a coastal area that has a basic wind speed of 100 mph or greater and is using R-Sheathing to resist the wind loading, must be designed by a design professional as a shear wall. Prescriptive wall bracing methods can not be used in this situation."
Martin described that particular rainscreen as "squishy" which can lead to a challenging installation and more broken shingles. The furring strips would certainly reduce this problem. A rain screen product called Sure Cavity from MTI would achieve the rain screen gap but is more rigid and less compressible than other drainage mats. They have a 1/8", 3/16" and 10mm version - I think the 3/16" would work behind shingles in cape cod.
Have you considered using cedar shingle panels to simplify the installation process?