Wall Assembly
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| Posted in Green Building Techniques on
I am building a house using advanced framing techniques. Right now the wall assembly is gypsum, dense packed cellulose, bldg paper, 1″ EPS, and stucco. The problem is, my husband hates stucco and wants siding. However, my architect is telling me there is no way to attach the siding and/or window trim. My assumption is a layer of OSB will compromise my energy efficiency. We live in Sacamento (mild climate). Any suggestions? Thanks.
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Replies
Laura,
Rather than installing a layer of OSB, you could install vertical furring strips over the foam. The furring strips are screwed through the foam into the studs. These furring strips provide a rainscreen drainage gap, as well as providing something solid to attach your siding to.
Thanks Martin. Could I re-use the lath from the old house as the furring strips? Do they need to be a certain size?
Laura,
The furring strips need to be thick enough to hold the siding nails securely, unless you intend to use very long siding nails that penetrate into the studs. For most siding types, 1x4 furring strips work well -- better than 1x3s, which sometimes split during installation.
OSB will not compromise your energy efficiency, but it is the least durable material for sheathing a house. However, the wall cross section you describe has no shear bracing, required by code, particularly in seismic zones (CA is very strict about this).
So you should have plywood sheathing applied directly to the studs or diagonal board sheathing or let-in metal T-bracing or prefabricated corner shear panels. Your house is structurally inadequate without one of these options.