EIFS Finished Systems

•         EIFS is built in layers, the outside shedding moisture, the inside holding in heat.  While all EIFS systems are alike in construction, there are two basic categories – “standard” and “ultrahigh impact.

•         The insulation layer is closet to the interior.  It also provides reinforcement.  The interior EIFS is insulation board made of either polystyrene or polyisocyanurate foam about 1" to 4" thick.  It is secured to the exterior wall surface with a special adhesive and/or mechanical attachment.  In  recent years, it often is applied on top of Tyvec or similar insulating moisture barriers for wood frames, which helped prevent problems.  Home inspectors cannot tell visually if this is the case.

•         Normally, an EIFS proprietary drainage board is applied outside the polystyrene.  A second layer of fiberglass EIFS reinforcing mesh is applied with an EIFS base coat which embeds the mesh.  Finally, the third layer is an exterior EIFS acrylic co-polymer finish coat (or “lamina”) that sheds water and protects both the interior layers and the building.  It also is both colorfast and crack resistant – giving superior resistance to fasing, chalking and yellowing.  Because it keeps its original appearance over time, EIFS offers both initial and life-cycle cost savings to owners.  The layers rest on a vinyl drainage track.

•         At its base, EIFS  systems should terminate a minimum of 8" above finished grade either with back-wrapping that is EIFS sealed and caulked or back-wrapping with EIFS mesh and base coating into the foundation.  Most EIFS applicators are sub-contractors, who leave the site before landscaping and finish work is done. 

•         Be alert for landscaping that is too near, or even overlaps, EIFS at points.  If there is no gap or too little gap between the EIFS and finish grade, it can permit wicking moisture in the foam, which invites termites.  (Damp EIFS foam is like a Club Med for termites.  Once termites move in, though, it’s impossible to treat.)

•         Flashings are needed to move water away from the structure.  There should be diverter flashings installed where a roof intersects a vertical wall.  Older diverter joints were soldered; modern ones are one-piece plastic units.  The areas where gutters meet sidewalls are often a point of EIFS moisture penetration.  Step flashing should extend at least 6" above the roof and any cricket or chimney enclosure.  Door, window and deck flashings also must be functioning.  Even though flashing has been a requirement for years, too many builders incorrectly believed that stucco exteriors did not need them.  They built structures that saved small amounts at high risk to the building.

•         Expansion joints are required at all floor lines, places where there is a change in substrate, areas with structural movement, and places where EIFS terminates against a different material, such as concrete block or plywood.  These joints are sealed with EIFS approved sealants and must be properly caulked.  In older installations, before silicone caulk was standard, caulking may be seen cracking or detaching today, which should be noted.  (It often can be repaired with pre-cured silicone sealants, which do not require removal of the old sealant, which can damage an EIFS substrate.)  In older installations, expansion joints generally were about ½"; more recent installations use 1" expansion joints.

•         Always look for signs of compression or gaps in EIFS expansion joints.  They show the siding, and often the building, are in motion and imply further evaluation for moisture problems is advisable.

•         Penetrations – especially windows and doors, but even pipes, fixtures, outlets, fasteners and other things attached to the cladding – are the major source of water intrusion for EIFS systems. 

•         Always check exterior windows, doors, and their casings and frames (windows and doors in modern homes probably were bought as packaged units) – especially where the units are wood.  Wood windows are much more vulnerable to water than aluminum or vinyl clad windows.  Be sure to check lower corners for softness, especially where there’s fresh paint.  Inspectors can use probes to check for damage too, as long as they’re not so enthusiastic they cause damage.

•         Look out for casement windows from the 1950s and 1960s; often they had single-glazed construction.  They performed poorly, typically having water leakage and condensation problems.  They should have been replaced in an EIFS house, but be sure.  Storm windows and screens usually are a sign of single-glazed windows.

•         Water flowing into EIFS systems and walls from leaky windows or doors can produce significant unseen damage.  Sills should be inclined away from the house, or water can table or pool at the sill and get wicked up into the window and its casing.  Deterioration follows quickly.   Windows installed backwards usually have a reverse sill slope.