Contributed by Eric D. Lussier
I’m quickly approaching eleven years working in and around indoor flooring, focusing mainly on sport and synthetic surfaces. Eleven years of projects of all shapes and sizes ranging from 250 square foot residential basements to 30,000 square foot college field houses. Eleven years of existing conditions, renovations, rehabilitations and new construction and the one constant that rears its ugly head on almost each job are substrate conditions, and especially concrete moisture. Conversely, said moisture issues are seemingly new news to whomever I am working with: whether that is architects, construction managers, general contractors or end users.
There are more than a few instances that can lead to high moisture in a concrete slab. Whether it is an over-watered pour, a lack of a quality vapor barrier, a compromised vapor barrier, or a missing one entirely (either from degradation or lack of placement), a fast track installation with insufficient time for the concrete to dry, an inoperable or missing HVAC system or a handful of other events. No matter the occurrence, it can all equate to the same headaches after the fact. Normally fingers are pointed, voices are raised, materials are ripped out and unnecessary time and money is spent to potentially repair or replace flooring that perhaps should have never been installed to begin with. Industry-speak may call it “flooring failure” but most of the time the flooring is performing exactly as it is supposed to. The adhesive on the other hand, may be completely failing.
New construction technologies have our buildings tighter than ever. With the use of a proper vapor barrier removing the ground from the equation, concrete moisture has no place to go but up and through the slab. When placing a fully adhered, non-breathing floor, such as a heat-welded sheet vinyl on the slab, concrete moisture in an untreated slab travels up and out, trying to push through the adhesive and new floor in the process. Even though the norm in the industry has raised from 3 lbs. of moisture to 5 lbs., as per ASTM F1869-11 (Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride), that limit can take substantial time to achieve when it comes to new construction.
Speaking of norms in the industry, thankfully most flooring manufacturers have moved away from recognizing calcium chloride testing (which is more of a snapshot of what is happening emanating from just the top of the slab) towards in-slab relative humidity (RH) testing (what is going on inside the slab). Testing as per ASTM F2170-11 (Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using In-Situ Probes (has become easier over the last handful of years with developed equipment, including testing probes that can be left in the slab and reusable digital probes. It is always recommended that an independent third-party is specified to test the concrete for moisture and not the General Contractor or flooring contractor themselves. It could be viewed that each party has a vested interest in ensuring that results are swayed their way. If you are looking for a certified concrete moisture testing party, the International Concrete Repair Institute offers a moisture testing certification program and you can search the certified testers here.
Contributed by Joseph Lstiburek of Building Science Corporation
The perfect wall is an environmental separator—it has to keep the outside out and the inside in. In order to do this the wall assembly has to control rain, air, vapor and heat. In the old days we had one material to do this: rocks. We would pile a bunch or rocks up and have the rocks do it all. But over time rocks lost their appeal. They were heavy and fell down a lot. Heavy means expensive and falling down is annoying. So construction evolved. Today walls need four principal control layers—especially if we don’t build out of rocks. They are presented in order of importance:
The best place for the control layers is to locate them on the outside of the structure in order to protect the structure (See Figure 1). When we built out of rocks the rocks didn’t need much protection. When we build out of steel and wood we need to protect the steel and wood. And since most of the bad stuff comes from outside the best place to control the bad stuff is on the outside of the structure before it gets to the structure.
Also, after generations of building out of rocks folks somehow got the idea that they wanted to be comfortable—and they figured out that rocks were not the best insulation. I mean rocks are not that bad compared to windows—memo to architects: you can’t build an energy efficient green building out of glass, but you can get design awards and we all know which is more important. Back to rocks, they are heavy and you need a lot of them to make the wall have any decent thermal resistance so we invented thermal insulation.
But where to put the insulation? If we put the insulation on the inside of the structure the insulation does not protect the structure from heat and cold. Remember we really do want to protect that darn structure—especially for the sake of making the structural engineers life more happy. Expansion, contraction, corrosion, decay, ultra violet radiation, and almost all bad things all are functions of temperature. So all the control layers go on the outside. Keep the structure from going through temperature extremes and protect it from water in its various forms and ultra violet radiation and life is good.
Figure 1 (Above): “The Perfect Wall”—In concept the perfect wall has the rainwater control layer, the air control layer, the vapor control layer and the thermal control layer on the exterior of the structure. The claddings function is principally to act a an ultra-violet screen. Oh, and architects might consider the aesthetics of the cladding to be important.
What about this air control thing? Well air can carry a lot of water and water is bad for the structure. So we have to keep air out of the structure as well because of the air-water thing—or if we let it get into the structure we have to make sure it does not get cold enough to drop its water. Now, just one other thing, tends to be important if you intend on living in the building or working in the building or keeping things safe in the building, we might want to control the interior environment. We especially ought to be concerned about what is in the interior air because when we are in the interior we tend to breathe it. Well, it turns out that we can’t control air until we enclose air. So we need an honest to god airtight enclosure in order to provide conditioning such as filtration and air change and temperature and humidity control. And once again the best place to control this air thing is on the outside of the structure—but under the insulation layer so the air does not change temperature. Presto: the perfect wall. A water control layer, air control layer and vapor control layer directly on the structure and a thermal control layer over the top of the other control layers (see Figure 1 again).
This was figured out long before I was born—I think the Canadians figured it out first , but the Norwegians have some claims to this plus the Russians. I am going to go with the Canadians on this one because I am biased and proud of it. Also, I met Professor Hutcheon, and that is a story for the grandkids when I get some—memo to Christy and Andrew: so what’s the delay here? For a more detailed discussion of the physics of all of this go to the old masters: Hutcheon and Handegord  and the new kids on the block Burnett and Straube .
In a beautiful bit of elegance and symmetry if you lie the perfect wall down you get the perfect roof (Figure 2) and then when you flip it the other way you get the perfect slab (Figure 3). The physics of walls, roofs and slabs are pretty much the same—no surprise (Figure 4). This insight was shone into a whole generation of practitioners by Max Baker  when I was first getting started.
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Contributed by Cherise Lakeside
This past February, for the first time, I attended the World of Concrete in Las Vegas. I was invited by the Tao Group for their Praxis event to do a presentation on Specs 101 for anyone who cared to attend. Tao Group is passionate about maintaining design intent and providing the best possible outcome for the Owner. I was thrilled to be asked to share some CSI contract document education with folks who traditionally do not get exposure to it.
Like anyone in our industry, I have areas where I am particularly passionate. One of those areas is better interaction and education for our emerging professionals. Another, and the subject of this blog, is improving communication, coordination and collaboration on our projects. I will take any opportunity that I can get to share this education across disciplines. I am especially grateful now that I had this opportunity at World of Concrete.
I would venture to guess that I get out of my specifier cave a little more than some due to my rather aggressive involvement in CSI and ever increasing speaking engagements. This gives me the chance to talk to folks from a lot of disciplines which is invaluable. What I learned this week is that I need to get my hands dirty.
Like a lot of people who work strictly as a specifier, I don’t have many opportunities to get out on the jobsites and talk to the people who are actually doing the work. There has been very little opportunity to get feedback from the people who are using and interpreting the specifications that I write. There has been almost no chance to see, first hand, how it all comes together. How it actually gets built.
This has been a critical mistake and it changes today.
I have done this Specs 101 class a number of times. It is geared to provide some very general knowledge of specifications, contract documents, roles and responsibilities and risk. You can only cover so much in 1.5 hours so I try to lightly hit a lot of pertinent areas to hopefully spark my attendees to ask more questions and get further education in contract documents and project delivery.
I have presented this class to architects, contractors, engineers, product reps and manufacturers – in and outside of CSI. Not once has anyone told me that the information was not helpful. The attendees always walk away with some homework they intend to do because I said something they didn’t know or didn’t understand.
At World of Concrete my audience for this particular presentation was approximately 50 concrete subcontractors. With the exception of a scattering of subs among my other presentations, I don’t typically see this group at CSI meetings or in my presentations. I was thrilled to have a chance to talk with them. I was thrilled not only because I want to know what I don’t know, but I also had a chance to clear up misconceptions about specifications. I wanted to learn how it really goes down once those documents leave my hands.
I started with a couple of questions:
Damn if I hadn’t just received a 2×4 smack in the head. How have I been missing this knowledgeable and valuable group in my CSI adventures! How have I not been getting this crucial feedback so that I can do a better job?
I also shared a few things with them:
It drives me insane when I see a continuing problem that doesn’t get fixed. What drives you crazy at work? That question always results in the areas we need to improve. This is one of those areas and change starts with me.
There is no way that I am taking on concrete issues in construction in this blog. I don’t even pretend to be knowledgeable enough to do that. BUT I will tell you what I am going to do:
Today, I invite my CSI compatriots to do the same.
World of Concrete was an amazing experience that I didn’t see coming. I now wish I would have stayed all week. I thank all of the subcontractors and tradesmen who took the time to share with me, show me things and let me play with the big toys. I have the utmost respect for the work that they do. I definitely hope to have the opportunity to attend next year and really get my hands dirty. I encourage anyone to go outside your industry and learn from others in the process.
Be the change you wish to see in this world!
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