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10 Steps for the Perfect EIFS Application

Filed under: EIFS — Tags: , , — procoat @ 4:55 pm February 17, 2019

EIFS, Exterior Insulation and Finish System, is a cladding technique designed to protect and insulate buildings while reducing energy costs. Though a very specific layering process, starting inside the building and extending to the outer wall, the EIFS process insulates while preventing moisture build-up within the system.

A ProCoat partner, Sto Corporation, is the industry leader in the development of EIFS treatment. Introducing StoTherm® in 1963, Sto has continued to perfect their EIFS process and has developed a next generation system named StoTherm EIFS NExT that adds a unified layer to the traditional system.

Sto™ Stucco is Perfect for Salt Lake CityHow Are EIFS Applied?

There are several steps to creating a proper EIFS application. Before beginning, make sure all components and scaffolding are on hand and all surfaces are prepared.


StoTherm EIFS can be installed over the glass-mat gypsum sheathing, wood-based sheathing, plywood, oriented strand board (OSB), masonry, plaster, concrete or stucco. The key element of EIFS is to ensure there is no moisture accumulation not contaminants within the systems.  A waterproof air barrier should be applied.

Damaged sheathing should be replaced.
Specially designed adhesives are used to fasten all elements in the EIFS structure.Metal fasteners should not be used since the conductivity of the metal contradicts the process of reducing energy.

  1. Backwrapping with Reinforcing Mesh

A reinforcing mesh is attached to the substrate with the adhesive.The mesh will, in fact, be holding the insulation board that will comes next by folding over or “backwrapping” around the edges of the board.

  1. Preparing the Insulation or EPS Board

While the minimum effective thickness of the insulation board is ¾-inch, most codes will allow up to 4 inches. When applying the boards, try to eliminate any gaps or thermal breaks between each piece. The insulation boards should be cut with a knife using a T-square to guide the cut.

  1. Adhesive Application

Apply the adhesive to the EPS with a notched trowel. The “ribbons” or lines of adhesive should run parallel to the long dimension of the board.

  1. Installing the Insulation Boards

Place the boards so there is no space between them to create breaks. After installation, check for any breaks or spaces. If there are any, even the width of a credit card, they must be filled with an insulating material.

  1. Rasping

Rasp the entire insulation board surface, not just the joints, with sandpaper to ensure they are level and smooth.

  1. Base Coat and Mesh Application

Apply a prescribed base coat to prevent sunlight from affecting the insulation board surface. Several Sto-approved base coat products are acceptable.

The mesh is then embedded until it is no longer visible through the base coat. If the mesh does show through, more base coat is necessary to cover it completely. Allow the base coat to dry. Primer may be used here for complete protection.

  1. Finish Coating

Apply the finish coat directly over the base coat in continuous application.

  1. Floating or Spraying Textures

Texture can be applied to the outer surface with various products and application methods. Sto offers stucco, limestone, various other textures to cover the EIFS.

  1. Sealant

The final protective step is the application of a sealant to any joints where the EPS boards may meet another surface like a doorframe or meter box. The sealant acts as a shock absorber between the two surfaces, stretching as the surfaces move.

Contact ProCoat

For more information regarding EIFS, contact the experts at ProCoat Systems at 303.322.9009.