What are EIFS Drainage Systems?

EIFS with drainage system are the most predominant method used today, over the conventional EIFS just as barrier. EIFS drainage system is a technology that provides a way for the moisture to accumulate in the wall cavity and later evacuates. The main purpose of EIFS drainage system is to preclude the moisture entering the wall from damaging the main supporting wall. EIFS are also called as synthetic stucco ( But not considered as stucco).

Fig.1. EIFS Drainage System 

An Exterior Insulation Finishing System (EIFS) or Exterior Wall Insulation Systems (EWI) or External Thermal Insulation Composite Systems ( ETICS) is an external cladding system used to provide insulation, finishing and waterproofing to the building exterior.

There are various versions of EIFS or ETICS system. The most basic form of EIFS system are as barrier system that are the conventional EIFS system that are applied to a solid wall that are made out of blockworks, masonry, precast panels etc. 

Read More on: Conventional EIFS System in Construction

Another form of EIFS systems are EIFS drainage systems which act as barrier along with water drainage capability. This is mainly applied to wooden structures.

Components of EIFS Drainage System

Conventional EIFS is a synthetic wall cladding that usually have a plastic insulation, foam and a synthetic coating. EIFS are usually placed on the building exterior, using a adhesive agent attached to gypsum board.

Fig.2. EIFS Drainage System

The main components of a EIFS drainage system are:

1. Water-resistive barrier (WRB): It covers the substrate as shown in fig.2. above.
2. Drainage Plane: This is provided between the WRB and the insulation board. These are vertical ribbons of adhesive applied over the WRB.
3. Insulation board: This can be either and EPS (expanded polystyrene) secured with an adhesive or mechanical fasteners. To know more on the type of insulation board used in EIFS system, Read More on: What is EIFS System in Construction
4. Glass-fiber reinforcing mesh: This mesh is embedded in the base coat.
5. Weather Barrier: A water resistant  base coat in applied on the top of the insulation to act as a barrier for weather actions.
6. Finish Coat: Colorfast and crack-resistant acrylic co-polymer technologies are used as a finish coat

Always a water resistive barrier (WRB) is installed over the substrate followed by the drainage cavity. Between the foam and the WRB space is created, that forms the drainage cavity. After which, the remaining layers are added.

EIFS drainage system is prominently used for wood frame construction. These system provide a path for the incidental water that get collected behind EIFS and later to take a safe route outside. 

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