Best practices for fastening lath / 3-coat stucco over rigid foam
There seems to be some debate over how to anchor 3-coat stucco over rigid foam while maintaining <1/64 deflection to avoid cracking. It seems that for: <=1″ Foam, Standard Wide Crown 2″ Staples into Studs are Adequate 2″ Foam, Lathe & Plaster Washers and 4″ #10 Screws every 6″ 4″ Foam, Furring strips or add additional OSB/CDX Sheathing over Foam and staple lath My question is, 1. What would you all recommend for 1-1/2″ Foam (R-Max Polyiso)? 2. Would there be any advantage to a hybridized system of staples and screws/washers – i.e. screws every 12″, staples every 4″ 3. Would staples anchored only in the OSB provide any benefit or is it simply a waste of time, money and resources?
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