For centuries, stucco has been a leading exterior cladding choice for commercial and residential buildings. Relatively easy to apply, resistant to bugs and moisture, and long-asting, stucco, which is a Portland cement mix, has understandably been the choice of many builders to handle their exterior finish details.
Dryvit is changing that–slowly but surely. Dryvit takes the best of stucco and combines it with a light-weight insulation system that greatly enhances the value of the system when compared to traditional stucco. Since Dryvit is installed over a type of Styrofoam backer, it is easy to create striking architectural details that surpass what is available with traditional stucco.
Apply the sheathing to the exterior wall. Sheathing for Dryvit is typically a paperless gypsum panel designed for exterior use such as DensGlass Gold by Georgia-Pacific. Plywood and oriented-strand board are sometimes used as well. The sheathing should be screwed in place and not nailed, following the manufacturers guidelines.
Adhere the expanded polystyrene (EPS) insulation on top of the sheathing by using a trowel to apply the adhesive on the face of the sheathing and then pressing the EPS in place. This adhesive is commonly a Portland cement-based product that comes either pre-mixed or as a powder that requires the addition of water. EPS is a white Styrofoam product that is similar to the ubiquitous white coffee cups and is commonly available in 2-feet by 4-feet sheets.
Install the base coat which consists of a fiberglass-mesh that is adhered to the EPS with the same cement-based adhesive used to attach the EPS to the sheathing. Trowel on the adhesive and then embed the mesh. Trim any excess mesh with a utility knife.
Apply the topcoat with a trowel. Topcoats come premixed in one- and five-gallon buckets and are available in a variety of colors–although they can be easily painted once they are installed and cured.
Caulk any joints between the Dryvit and surrounding materials, such as brick or concrete. Use a quality outdoor caulk such as NP1 by BASF/Sonneborn.