A wall with EIFS and SIS — What’s the vapor profile?
I need a little help with a wall detail, for a three story house we’re building in Arlington VA, Zone 4a mixed humid.
The lower 2/3 of the wall will be clad with EIFS. The upper 1/3 will be clad with a cementitious shake panel. The two finishes are separated by a water-table/apron like trim detail. 1″ XPS will be continuous over the SIS on 2×6 framing with blown cellulose inclosed with ADA drywall. Cementous shake installed with rain screen, firring strips over XPS, flashed over the water-table trim.
A typical detail would be EIFS over a drain mat over WRB over sheathing. How does replacing the OSB with SIS change the vapor profile? Where should the drain mat be placed and for that matter the WRB?
The roof is a cathedral ceiling framed with trusses giving us 18″ at heal and on slope. Probably blown fiberglass with vents under the sheathing, continuous soffit and ridge vents, asphalt shingles, 4′ overhangs, no ceiling penetrations except surface mounted light boxes. Poured basement walls with continuous internal XPS and 3 1/2″ cellulose in wall cavities.
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