Finish Line: The Finish Line
August 25, 2009
I’m going to stick my neck out a bit in this month’s column; it contains my opinions from a lot of experience. But in doing so, I hope it will help you. Over the years, I’ve heard a zillion tales about EIFS and a lot of them are not true. I am not a lawyer and this is not legal advice but I think you’ll agree with my secret observations.
In the end, there are a lot of secrets or “true-isms” about EIFS that can make or break an EIFS project. Here are some you need to know about.
FROZEN EIFS MATERIALS
If you live up north, sometimes you want to get the building closed in before it gets really cold, right? Yet, in the colder months, the subject of “is EIFS OK to use?” comes up. It other words, “Is it frozen?” Good question.
The quick answer is that it’s very difficult to tell if it is OK to use. In talking with EIFS producers and their resin suppliers, they say the same thing: “It is hard to tell.” Unless the bucket is frozen solid as a rock, it’s a guess. The fact that it went below freezing the other night and the EIFS wet materials were not kept warm does not mean the EIFS got frozen-it takes awhile to freeze a 5-gallon pail. The safe course for the contractor is to not use it but sometimes the pressure is great to get it on the wall.
The problem is that you may be able to get it onto the wall and then next year the EIFS falls off and a lawyer shows up at your door.
The fact is that it is truly difficult to tell if the adhesive or finish is so messed up by the cold that it won’t work. Even sophisticated chemical analysis equipment can often not tell if a given batch is bad, unless it is truly beyond hope.
Some EIFS producers use heated vehicles to ship the product during the winter. This helps. But it’s got to be stored warm, too. Also, sometimes EIFS producers attach temperature sensors to the pails that indicate the lowest temperature near the pail (sort of like the thermometers used on Thanksgiving turkeys).
So, if you are thinking of hiring a lawyer, a testing lab or an expert who can verify that the material is no good, think again. In the end, it is very difficult to prove (even under oath-the acid test) that the material is bad, unless it is frozen solid.
Just because it was 31 degrees Fahrenheit or below near the pail does not mean the contents got frozen and are unusable. The bottom line is: if in doubt, throw it out. Get all the details, put them in writing, alert the GC, and call your insurance agent and your lawyer.
EIFS producers, in their published literature, usually state that the EIFS should be installed at 40 degrees Fahrenheit or above. Actually, some are more specific, and say that the substrate also needs to be at 40 degree Fahrenheit or above. How often is this true?
It’s not uncommon in the fall or winter for the air temperature to be 40 degrees or higher but how cold is the substrate, really? If it is below 32 degrees Fahrenheit, when the water-based adhesive comes in contact with it, the heat gets sucked out of the warmer adhesive. The result: a bad bond. The badness does not usually show up right away, but down the road, the wall may end up on the ground.
This can be particularly true on solid, massive substrates like concrete, which can hold their heat (or cold) for long periods. Lightweight substrates, such as gypsum-based sheathing, tend to warm up to the ambient air temperature more quickly.
Frozen substrates do not include only the wall to which the EIFS is attached. Take a look at the photo on the next page of a peeled-back EIFS lamina. What is wrong with this picture?
Two things are wrong, actually. One is the bond of the EIFS basecoat to the foam-there isn’t any. There should be hunks of EPS beads on the backside of the lamina, but they aren’t there. This can be caused by the basecoat being applied when it’s too cold-and a proper bond of the basecoat adhesive to the foam doesn’t occur.
The other problem is the gap between the foam board edges-this can cause cracks. Note the gap between the board edges and the rivlet on the backside of the basecoat.
Noncementitous adhesives dry by the evaporation of water, like house paint. The evaporation process is sped up by higher temperatures and lower humidity. Thus, cool, damp weather slows down the curing process for this type of adhesive. The reason is because cementitious adhesives set up by a chemical reaction between the water and the Portland cement-not by humidity and temperature-and are less affected by the ambient climate.
When using noncementitious attachment adhesives in a cool, damp climate, the adhesive can take an eternity to set up. This is because the adhesive is trapped between the insulation and substrate. Working further on a wall where the attachment adhesive has not set up is risky (such as applying the basecoat), and thus the movement of the insulation can disrupt the formation of a proper bond to the substrate. The moral: allow extra time when using noncementitious adhesives in cool, damp climates.
THE REAL PURPOSE OF MESH
Many times I’ve heard that you can leave out the reinforcing mesh and the EIFS will perform fine. The thinking behind this concept is that the mesh is there to provide impact resistance only. Not true. The mesh’s primary purpose is to hold the edge of the EIFS insulation boards together as they expand and contract with temperature changes. Without the mesh, cracks will form at the edge of the insulation boards.
THE KEY TO A GOOD EIFS PROJECT
EIFS is hand-made from raw materials at the construction site, and the diligence and craftsmanship is all-important.
In some markets, a specific EIFS producer dominates the sales. This usually is because of a close relationship with the distributor and the distributor’s close relationship with its customers.
Many EIFS contractors install several brands of EIFS. EIFS has become a commodity and there are many quality EIFS products and competitive prices. A hint: if you are a owner/specifier, work backwards and find out who has the best reputation for quality EIFS workmanship in your area, and then work with the local EIFS distributor and EIFS supplier to get the EIFS of your choice specified.
THE PERIMETER MATTERS
If you get involved with a building that has a leak problem, don’t waste your time staring at the field of the wall. Unless there are visible cracks in the field, the water isn’t getting in there. In my many decades with EIFS, I can count on one hand the number of times I’ve seen leaks that came through the coating or from cracks in the field of the wall.
Spend your time looking at the perimeter of the EIFS. Look where the EIFS stops and transitions to another material, such as caulking, flashing, windows or any type of opening, such as a beam or an HVAC unit. Even if the caulking appears to be bonded to the EIFS, give it a nudge to see if it is merely in contact, but not bonded. When the joint opens up (gets wider) as it gets cool, water can slip inbetween the unbonded caulking and the EIFS.
EIFS WITH DRAINAGE
In the 1990s, when EIFS with drainage was introduced, I was surprised that the approach was to put the drainage capability everywhere behind the EIFS. This included vast wall areas with no openings. I ask you: “How is the water leak supposed to occur there?”
As noted earlier, leaks occur at the perimeter of the EIFS and that’s were the drainage is actually needed. Sure the drainage cavity and the water resistive barrier and the various sealant materials do need to surround openings and terminations, but not the whole wall. All the extra time and money to drain the whole wall, is in my opinion, unnecessary.
EIFS IN EUROPE
I’m often asked how long EIFS will last. I do not have a crystal ball to predict the ultimate lifespan of EIFS, but I can speak about what I’ve seen.
I’ve seen EIFS jobs in central Europe that go back to right after World War II. They look fine, and other than being painted due to getting dirty with age, there’s no evidence that they are losing their performance or looks. The oldest EIFS jobs I’ve seen in the United States go back to the early ’70s, and are also doing fine.
Is comparing the two locations fair? I would say somewhat. There are differences. In Europe, the substrate is usually masonry or concrete. The coatings are thicker and simple, durable flashings are used. In North America, lightweight stud and sheathing substrates are common, and making the EIFS look fancy is in vogue. In both markets the resins used in the adhesives and finish coatings are much better now than what was available right after WWII, and this contributes to longevity.
So how long will EIFS last? “Long enough” is a good answer. In North America, most buildings are not designed to last for hundreds of years-not even spectacular buildings like The Bellagio in Las Vegas. The exception is monumental buildings, usually those operated by the government. For normal uses, EIFS, when correctly installed and maintained, has a lifespan more than adequate for its intended use.
A FINAL SECRET
The final secret is that the EIFS market is changing. Now a mature product with a well established performance and a devoted cadre of users, EIFS is a mainstay in the wall business. Also, like all building products, EIFS will go through a cycle of popularity, and eventually need to change. The “EIFS look” is so common that designers are looking for something new. Fortunately for EIFS, its versatility lends itself to new looks. This extends EIFS viability as an established product.
An example is the trend toward extensive use of foam shapes to give EIFS buildings the look of stone-a sort of “nouveau old” look-instead of the traditional smooth, flat EIFS appearance. I see EIFS having a bright, long-term future. Like stucco, EIFS will remain popular, and no doubt will morph into a “next generation” EIFS with even better looks, performance and ease of installation. W&C