How to Install Stucco Finish Polyurethane Insulation

Stucco finish polyurethane insulation is one type of exterior insulation and finishing system, or EIFS. This type of finish is an exterior wall that is non-load bearing. It has many advantages, such as weather-resistant coating, low installation cost, low maintenance, seamless covering and energy savings.

Ensure that you follow the correct EIFS installation steps for your area, by checking with the local building inspector to learn which steps to take.

  1. Cut the rigid insulation boards to size if necessary. Use a sharp knife and cut at an angle of 30 degrees or less. This low cutting angle slices the boards neatly. Use the carpenter's square when cutting to ensure a straight and even cut. You can also cut the boards with a hot wire machine or table saw.

  2. Apply the insulation board adhesive to the back of the insulation board. Apply the adhesive using a trowel held at a 30 degree angle or greater. This angle produces the necessary ribbons. Spread the adhesive along the long side of the insulation board. When applied to the wall, these ribbons should run horizontal to the ground.

  3. Wipe away any excess adhesive from the insulation boards using the cloth. You do not want any adhesive to gather at the edges or between boards. Apply the boards directly to the exterior of the house. Press each board tightly up against the previously placed board. Place the boards like stacking bricks. The vertical joints should be staggered. Press down on the boards until the adhesive grabs the wall. Press down over the entire insulation board with the rasping board. This ensures that the entire board is level when applying pressure.

  4. Cut the insulation boards to fit around openings for windows and doors. Do not align any board joints with the corners of these openings.

  5. Fill any large gaps not covered by the insulation board with the polyurethane spray foam or scraps of the insulation board.

  6. Paint the base coat over the insulation boards. Aim to apply a layer that is three millimeters thick. Immediately press the mesh into the base coat. Make sure that the mesh is completely embedded in the base coat. Apply additional base coat if you can still see the mesh. If there is too much base coat, wipe away the excess. When applying the mesh, overlap the edges by two and a half inches. Feather the base coat where the mesh pieces overlap. Allow the base coat to thoroughly dry, approximately 24 hours.

  7. Mix the stucco finish coat in a clean mixer or bucket. Two people are needed to apply the finish. Use the stainless steel trowel to apply the finish directly to the base coat. Add the finish in a continuous manner working from the wet edge of the previously placed finish to uncovered areas. The second person will follow the first and use a plastic trowel to float the finish. This produces a rilled, stucco finish. Movement in a figure eight produces a pebbled texture. Rills are produces by moving the trowel in a figure eight in both the vertical and horizontal direction. You can also apply texture using a brush, sponge, putty knife or roller. The choice is yours.