Download PDF version (2626.6k) Log In or Register to view the full article as a PDF document.

Launch Slideshow

EIFS Revisited

EIFS Revisited

  • http://www.jlconline.com/Images/965860020_1012_JLC_EIFS_00a_tcm96-1079549.jpg

    true

    600

  • http://www.jlconline.com/Images/1743310768_1012_JLC_EIFS_01a_tcm96-1079550.jpg

    true

    600

    Before applying the WeatherSeal elastomeric waterproofing membrane, workers use plywood and duct tape to prevent the coating from dripping onto a concrete porch floor.

  • http://www.jlconline.com/Images/904830581_1012_JLC_EIFS_01b_tcm96-1079551.jpg

    true

    600

    The blue membrane is troweled onto seams and joints.

  • http://www.jlconline.com/Images/1607406250_1012_JLC_EIFS_01c_tcm96-1079552.jpg

    true

    600

    The membrane is reinforced with a special joint tape.

  • http://www.jlconline.com/Images/768926063_1012_JLC_EIFS_01d_tcm96-1079553.jpg

    true

    600

    Once the joints are treated, the entire surface will be skim-coated with the membrane.

  • http://www.jlconline.com/Images/281817767_1012_JLC_EIFS_02a_tcm96-1079554.jpg

    true

    600

    Once the WeatherSeal membrane has been installed, DrainEdge termination strips are stapled over door and window openings, followed by backwrapping mesh.

  • http://www.jlconline.com/Images/213865508_1012_JLC_EIFS_02b_tcm96-1079555.jpg

    true

    600

    The EPS panels are glued to the walls with adhesive that's been applied with a notched trowel. The notches are vertically oriented so that moisture can drain down the channels between the membrane and the foam and out of the wall assembly wherever the DrainEdge has been installed.

  • http://www.jlconline.com/Images/1103712931_1012_JLC_EIFS_02c_tcm96-1079556.jpg

    true

    600

    Installing the EPS panels.

  • http://www.jlconline.com/Images/1454916709_1012_JLC_EIFS_03a_tcm96-1079557.jpg

    true

    600

    Molded polyethylene kick-out flashings, like this one from Raintek, can be trimmed to fit different foam thicknesses. Kick-out flashings are installed with the step flashings.

  • http://www.jlconline.com/Images/548652376_1012_JLC_EIFS_03b_tcm96-1079558.jpg

    true

    600

  • http://www.jlconline.com/Images/1319012191_1012_JLC_EIFS_03c_tcm96-1079559.jpg

    true

    600

  • http://www.jlconline.com/Images/1063788178_1012_JLC_EIFS_03d_tcm96-1079560.jpg

    true

    600

  • http://www.jlconline.com/Images/38036237_1012_JLC_EIFS_04a_tcm96-1079561.jpg

    true

    600

    The author fabricates trim details like these bullnose returns with a hot wire cutter.

  • http://www.jlconline.com/Images/576511769_1012_JLC_EIFS_04b_tcm96-1079562.jpg

    true

    600

    After the foam has been glued to the walls, all of the gaps between panels are filled with spray foam.

  • http://www.jlconline.com/Images/1047203155_1012_JLC_EIFS_05a_tcm96-1079563.jpg

    true

    600

    Base-coat application can begin after the foam has been leveled with a rasping board and abraded with a grit-welded float. Inside and outside corners get a double thickness of reinforcing mesh bedded in the base coat.

  • http://www.jlconline.com/Images/979250896_1012_JLC_EIFS_05b_tcm96-1079564.jpg

    true

    600

    To help with adhesion, these walls received a second base coat, which was then scratched with diamond mesh lath.

  • http://www.jlconline.com/Images/72986563_1012_JLC_EIFS_06a_tcm96-1079565.jpg

    true

    600

    Most EIF systems have a smooth and uniform finish coat, but this home was given a deeply textured finish coat to match the Mediterranean architecture.

  • http://www.jlconline.com/Images/543677949_1012_JLC_EIFS_07a_tcm96-1079566.jpg

    true

    600

    Expansion joints are needed in EIFS cladding wherever two dissimilar substrates meet, such as at the foundation.

  • http://www.jlconline.com/Images/1082153481_1012_JLC_EIFS_08a_tcm96-1079567.jpg

    true

    600

    Corbels and other architectural details can be added to EIFS cladding by gluing foam profiles to the EPS before applying the base coat and finish. Areas that don’t require insulation, like the columns supporting the arches on this home, can be wrapped with cement backerboard instead of foam, which gives them better impact resistance.

  • http://www.jlconline.com/Images/1552844867_1012_JLC_EIFS_08b_tcm96-1079568.jpg

    true

    600

    The finished project

Waterproofing

Like housewrap used under other types of siding, the WeatherSeal membrane also acts as a vapor-permeable air barrier (7 perms at 20 mils thick). It’s an acrylic product that can be brushed, sprayed, or rolled on, but I prefer to use the more viscous trowel-applied grade. This forms a thicker coat — more than 60 mils, or 1/16 inch, compared with around 10 to 12 mils for the spray/roll formulation. The thicker coat tends to be self-gasketing around staples or other fasteners that puncture it.

Applying the toothpaste-like membrane is a lot like taping drywall. We begin by troweling it onto joints and seams; then we bed Parex 396 nonwoven fabric sheathing tape in the WeatherSeal. We wrap the door and window openings first, starting at the sills and working up through the jambs and headers. Once we’re done with these openings, we leave the job until the doors and windows are installed.

When we return with our full scaffolding, we finish taping the seams, corners, butt joints, and flanges and flashings. Then we skim-coat the remaining surfaces, building up the membrane until it is opaque enough that no letters on the sheathing show through.

Kick-out flashings. Even though metal step and cap flashings are typically the responsibility of the general contractor, we always carry a selection of kick-out flashings with us and install them as needed. Twenty years ago, nobody in our area was using these flashings, but I’ve seen how valuable they are in diverting water away from the walls at tricky roof-wall intersections — for instance, where a lower roof intersects a vertical wall.

Foundation. EIFS should terminate 6 to 8 inches above grade, but often the foundation walls are insulated with foam as well. If that’s the case and the foundation wall and sheathing are in the same plane, we leave a gap between the wall and foundation foam for expansion and drainage. When we trowel on the WeatherSeal membrane, we lap the tape over the dampproofing a couple of inches.

Weather. Like all of the acrylic and portland cement products we use in our stucco business, WeatherSeal can be damaged by freezing temperatures, but otherwise it’s quite weather-friendly. For example, if the temperature is 35°F and the day is supposed to warm up, we’ll start applying the membrane on the sunny side of the house. But if the forecast is for freezing overnight temperatures, we won’t apply the membrane even if the current conditions meet the manufacturer’s recommended 40-degree minimum temperature.

Once applied, the water-based membrane shouldn’t be exposed to standing water or heavy rain. Light rains, on the other hand, don’t seem to affect it. Protective gear isn’t needed when applying WeatherSeal, and the material cleans up easily with water. EIFS Installation Details

  • Image
    Weep holes above windows and doors allow water to exit the EIFS cladding. The weeps are typically short lengths of small-diameter plastic tubing that slip underneath the backer rod and sealant.