“Moisture is the Essence of Wetness”
This is a memorable line from a comedic movie made some time ago that caught my attention. It was meant to be humorous, but it struck me as an interesting comment concerning our construction industry today especially when it comes to flooring and concrete.
I remember the days of old when it was rare to hear about moisture problems with concrete slabs. But today? It is a quite common problem. Why? The answer to this stems from many reasons as outlined herein and cause rise for careful considerations for the design and construction of concrete slabs and the selection of flooring types that include installation systems that can accommodate today’s more challenging environment.
THE INDUSTRY HAS EVOLVED
Concrete has been around for a very long time. So what’s the difference today and why so much communication about water problems?
The industry has evolved. Construction schedules are considerably faster than ever before. What used to take perhaps a year or two to build, in many cases is done today in record time. As a general rule of thumb, under ideal conditions a typical concrete slab takes the first month to “cure” enough to reach compressive strength and then approximately 41 days for every inch of the pour. So a 6” concrete base can take approximately 7 months to be “dry” enough to receive many flooring types. “Ideal” conditions means the slab is not subjected to rain. If it rains? The clock starts all over again. Also, mechanical finishing of the surface along with some sealers that are applied (ASTM F710 makes reference to not having them) creates a very dense surface which can impede the free water from leaving the slab which needs to happen. The drive throughout this evolution in construction has been to build it faster, smarter, and cheaper. This certainly pushes for innovation continuously in order to meet those demands. It is undeniable however, that at times it seems the left hand doesn’t know what the right hand is doing from design, to construction, to finished product. Communication is a key element to successful implementation. I have more on communication below.
ADHESIVES HAVE CHANGED
Adhesives have changed. Given the understanding of VOC’s and responsible indoor environmental care, the “good stuff” which may have contained less than desirable components, were removed. There was a learning curve with the creation of new adhesives and how they performed compared to the less healthier adhesives from a long time ago. It is encouraging that today, adhesives are either very low VOC or VOC free and yet they can perform as good if not better than what we had before. It has taken time to get there. Adhesives today can have considerably higher moisture tolerances than ever before. Again, the needs have driven for innovation. But still, it is best when concrete along with its building envelope is stable and predictable.
TESTING HAS EVOLVED
Contractors have learned the importance of testing and there are educational services now that teach and certify slab testing. Failures due to moisture problems has caused this to occur. When a flooring system does fail because of this, it can be like the “Gun Fight at the OK Corral” with everyone pointing fingers. So testing is paramount with most flooring to understand what is happening with the slab prior to installation. There is still the lingering debate about who performs those tests. Professionals trained and experienced with these processes should be the rule of thumb. Now that testing is generally mandatory and more of it is being done, the rise of moisture mitigation systems is dramatic. But they also increase the capital cost of a flooring project. I have seen enough of them cost as much as the flooring did in the first place. UGH!
SO WHAT’S OUT THERE TODAY?
Better documents such as ACI 302.2R discusses the design and construction of concrete slabs to receive moisture sensitive floor coverings. This stems from a collaborative effort between ASTM and ACI. ASTM F710 discusses the preparation of concrete slabs to receive resilient flooring but can also be used for soft surfaces such as carpet, wood flooring, and other flooring types. With our new means of communication, training events can be held much easier and with less cost so I foresee (and have seen already) an easier connection from manufacturer, to contractor, to customer, to GC, and Architects. This will foster the spread of good and current information. “Knowing what you know.” is the best place to be for a lot of reasons. It is important to understand the interconnections between concrete and the flooring intended to be used upon it. Information is far easier to reach as of today which is quite encouraging. Skilled and experienced labor is needed especially for specialty materials such as sport flooring. As hands on training is a challenge today, this new found mode of virtual training is a blessing. Contact is so much easier now. I use Face-time and other virtual conference calling methods almost daily and it works. Solving problems in real time whether in an architect’s office or on a job site is considerably more efficient and we still get to have some semblance of human contact.
Also, installation products such as the aforementioned adhesive improvements, are slip sheet membrane systems which albeit have been around a while, their benefits were not completely understood. Not only to do these assist with higher moisture tolerances, but they also help with eventual cracking and minor joint movement which can compromise other types of mitigation systems. Slip sheet systems today can be sort of the trifecta of ideals.
1.) Higher moisture tolerance.
2.) Can be used over existing materials.
3.) Can help with cracks, non-moving and expansion contraction joints.
Given the lifespan of most sports floors, the benefit of the product being easy to remove is there but the other benefits far outweigh this particular aspect. There is one more benefit with these. They are cost effective and warranted by the manufacturer typically. A single source solution is an attractive selection for most owners.
So to conclude, it really is an exciting time. Yes, there can be problems as with all things in life but the options to either avoid or accommodate most challenges are here. The capacity to communicate with documentation and explanation is far easier and faster today. The ability to have a conference with multiple parties involved with any project is almost instantaneous and quite effective. There are systems available that can manage most things and they meet the whole concept of “faster, smarter, cheaper”. Having a great product, a good system in accordance with the project, and communication beforehand? This is the best way to avoid problems later and fortunately for everyone, communication is much easier today.
Tarkett Indoor Sports Technical Manager North America