The Finish Line: EIFS - Bits and Pieces
This month, instead of having the column be a single topic, I’m going to have a lot of small topics. Most of these are things that I have seen or heard over the years; a compendium of bits and pieces of information about EIFS.
At this strip mall, maintenance people and tenants were leaning ladders against the cap and denting it. These plastic signs were spaced about every 50 feet, and kept workers off the cap.
Inspection of EIFS as it is being installed is becoming more and more common. In fact, in some cases, it is mandated by the building codes and is written into the specs for a project, especially on high-end buildings. At present, there is no standard approved way of doing a basic inspection, let alone a comprehensive one. Although there are a number of inspection training programs and protocols by third-party groups, there does not currently exist a comprehensive standard by a national consensus organization. That is about to change.
ASTM has taken on the task of developing one. The first draft is out and it includes a number of concepts:
It is for the simplest inspection that will actually be effective.
It does not include prefab panels.
It does not tell the inspector specifically how to do his job but rather the type of issues that need to be inspected.
It does not include destructive disassembly of the wall, nor testing.
It does not include engineering or design review.
It does include consideration of local practices, the contract documents, EIFS producers’ requirements, industry standards, and code requirements.
It can be used on retrofit projects.
The development of this standard has already caused a bit of conversation, as views differ greatly about even basic things like its content and scope, and “who is a qualified inspector?”
This new standard will at least level the playing field so that designers and specifiers can point to a basic set of guidelines that have been developed with input from a wide range of shareholders. If you have an interest in the development of this ASTM specification, you can participate by joining ASTM committee E06.58. You can see the status of this spec, as it is being developed, and vote on it, if you join the E06.58 committee. Go to www.astm.org and look up Work Item 23983 under the “Technical Committees” section of the Web site.
Parapet Damage
It’s no secret that large foam parapet caps can get mangled by people working on the roof. Photo 1 shows a quasi solution at a strip mall, where maintenance people and tenants were leaning ladders against the cap and denting it. These plastic signs were spaced about every 50 feet, and kept workers off the cap. In the end, the mall owner ended up putting a sheet metal flashing over the cap, as the EIFS surface was wearing out anyway, due to weather.
Foam Shapes
Foam shapes can be done in a number of ways. One is to make them an integral part of the EIFS using the same EIFS material as the rest of the wall. The resulting base layer of foam (with shapes of foam added onto the base layer to create columns, arches, quoins, etc.) is then covered continuously with the EIFS lamina. Another is to precoat the foam shape at the warehouse, bring it to the site and bond it to an already-in-place basecoat layer. In this latter case, whether the foam shape is made of EIFS or some EIFS-like material doesn’t matter, as the foam shape is actually an add-on product in the form of a decorative trim, rather than a wall system.
Some installers attach the foam shape with thick vertical ribbons of adhesive. They then leave the bottom edge open so any water that gets behind the foam shape can drain out. It’s also possible to achieve a cut stone look by butting the ends of the shapes close to each other and using a sealant that looks like grout (granular surface appearance) to form a realistic-looking mortar joint. The same sealant is used at the top and sides of the foam shapes.
The soffit and adjacent fascia were ripped off, down to the studs, by Hurricane Katrina.
Despite using heavy-duty mesh near sidewalks and stores fronts, the EIFS still seems to get dinged and needs to be patched. Tired of this, storeowners sometimes put heavy sheet metal angles on the corners of columns. The problem, with shopping carts and lawnmowers and the like, is they simply can come right up against the wall. A solution I’ve seen that looks good and works is to use a line of hard material at the very bottom edge of the wall that protrudes a couple of inches past the outside face of the EIFS. Cast stone looks good but pavers and even solid block will work.
EIFS Soffits
EIFS is intended for use on walls, not roofs or roof-like surfaces, nor as large soffits. I do not consider the small returns at the heads on windows to be soffits but rather an extension of the wall. But on large soffits, such as the covered entranceway at the main door to a hotel, it’s a different story. On such large soffits, there are two problems.
The first is fire. Heat rises and can pass through the EIFS lamina, melting the foam. With no foam in place, there’s nothing to support the EIFS coatings, so the soffit collapses.
The second is wind uplift. EIFS is light, and if the structure that supports the EIFS (metal framing and sheathing, usually) is not rigid, wind swirling under the soffit can lift the soffit and make it flutter, causing cracks. This is especially true if a “hanging ceiling” type support system is used, employing hanger wire and channel iron.
The soffit and adjacent fascia in Photo 2 were ripped off, down to the studs, by Hurricane Katrina. The adjacent highlighted soffit area was cracked on many of the condo balconies.
Sealer on Window Sills
EIFS window sills that do not have flashings can pick up dirt and look bad. The dirt is hard to remove, as it gets embedded into the EIFS finish coating when the coating is damp and soft. Even aggressive scrubbing will sometimes not remove the dirt. Mildew can also form, leading to additional streaks on the adjacent vertical part of the wall.
One solution that helps is to seal the surface with a hard, clear coating. Hardness is important, as it helps keep dirt from getting locked into the surface. The sealer fills the texture, reducing the depth of the texture grooves in the EIFS finish, and also makes the water flow off better. Clear acrylics are available as brush or roller applied paint-like materials. Once installed, they are hard to detect from inside or outside. This technique also works on parapet caps and on top of balcony railings.
EPS Illustration: On the left, a thin piece of EPS cut to fit the contour of an EPS foam shape that would fit up under an eave overhang. The drawing at right shows the EPS spacer in place, prior to installing the next foam shape. Note the offset from the visible front edge of the foam shape for the grout.
Sometimes, samples of the EIFS need to be taken to check for the thickness of the basecoat and the presence of the right number and thickness of reinforcing mesh. No matter how it’s done, it leaves a hole, which usually results in a visible patch. An easy way to remove samples is to use a carbide-tipped hole saw. Using a husky cordless drill, you can drill through the lamina into the foam, and rock the drill side-to-side, and snap off a cylinder of foam and lamina. The sample can then be inspected by looking at it from the side. The thickness can even be measured using a hand-held micrometer.
You do need to use a carbide tipped hole saw, as carbon steel will get dull in short order. Another advantage of this technique is that the sample that was removed can be replaced into the hole from which it came, and caulked to be watertight and less visible (using color-matched sealant as an adhesive). Then a proper patch can be done at a later date.
Substitute for Foam Shapes: EPS
Ever tried to get a sealant backer rod into a joint that is profiled, such as a curvy foam shape decorative crown molding at the top of a wall that has grout-like joints between the foam shape pieces? It’s finnicky to try to stuff the backer rod into the joint and get the depth exactly right, or to turn sharp corners.
Instead, use a piece of flat EPS board stock that is the same thickness as the joint width, and contour it to fit the profile of the foam shape, less the difference of the sealant bead depth. Put up the first foam shape, affix the EPS spacer, and then abut the next shape. The joint width and depth will be exact.
You can make the spacers using a plywood template and a hot knife on rainy days. Or if you need a lot of spacers, get an EPS molder to cut the contour from a block and then have him slice it into individual spacers. This technique also has the benefit that it insulates the joint, giving a slight increase in energy efficiency while helping reduce condensation in the joint.
“Real” backer rod should be used for most joints but this technique works for complicated surface profiles. Also, make sure the sealant is compatible with EPS-some sealants have solvents that will dissolve the EPS.
The illustration show on page 51 is a thin piece of EPS cut to fit the contour of an EPS foam shape that would fit up under an eave overhang. The drawing shows the EPS spacer in place, prior to installing the next foam shape. Note the offset from the visible front edge of the foam shape for the grout.
The Finish Line
No doubt you’ve run into some interesting adventures and tips and techniques in your work with EIFS. Please send them to me TheFinishLine@eifs , and I’ll answer your questions in this column. W&C
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