Moisture and Flooring:  Problems, Causes, and Solutions

As annual insurance claims due to moisture-related flooring failures and conditions have soared into the billions of dollars, many design professionals are seeking to better understand the cause of the problems.  Health concerns have sureged to the forefront of our litigious society, making it more critical than ever to learn what has happened to accelerate these situations to such an alarming rate.

While multi-million-dollar individual claims are not uncommon, one example that comes to mind cost the architect's errors and omissions insurance carrier $1 million to settle out of court to avoid a potetential $10 million lawsuit.  All this occurred because of inadequate specification and poor construction practices that resulted in modl growth throughout the building due to severe moisture insturusion through the concrete.  This caused every type of flooring material in a 100,000 square foot building to fail.

Problems and Causes
     Flooring and concrete-related products have changed over the years, and this had lead to each industry blaming the other for the increase in flooirng failures.  Due to EPA regulations, both industries have had to change with regard to manufacturing and disposal.  These changes have resulted in significant performance and compatibility issues.  In the case of florring and concrete, some examples of these changes include asbestos, tricholrethane, volatile organic compounds (VOCs), environmental restrictions, outdated guidelines, and more.
     By the middle of the 1980s the majority of floor covering manufacturers ceased using asbestos in thheir products.  Asbestos iis no longer used in building products because of environmental and health concerns.  Industry experts continue to debate on the subject regrading flooring materials that contained asbestos versus the newer flooring materials to their tolerance of excessive substrate moisture vapor emissions.
     In the mid-1990s the use of 1,1,1, tricholrethane was curtailed in adhesives due to environmental and health concerns.  As a result, modifications and changes to adhesives have occured.
     VOC's combine in the atmosphere with other chemicals to form gruound-levl ozone.  The Federal Clean Air Act Amendments of 1990 gives the EPA authority to control VOC emissions for products.  In 1999, the EPA mandated a reduction in VOC levels for consutmer products.  For the concrte industry, the EPA ruling on VOCs affects the follwing materials:
          *  form release agents
          *  curing compounds
          *  dampproofing materials
          *  wall and floor coatings and primers
          *  membranes
          *  sealers
          *  water repellents
For the flooring industry, these products are affected:
          *  adhesives
          *  seam sealers
          *  manufacturing processes
          *  maintenance products
Environmental restrictions have also imposed strigent rules and regulations concerning emission of kiln gases and fines into the atmospher.  This has led to some alterations in composition of cement, eventually affecting the properties of concrete.
     Due to high demand, the industry is engineering products from various resources (e.g., yound and older trees), but failing to rememer these products are still made of materials that respond to temperature, humidity, and/or moisture. 
     Other situations impacting successful builds have more to do with the human element.  Some are:
          *  Fast-track and vaule engineering driven by time and budget only and not taking into regard any of htese issues addressed throughout this section.
          *  Poorly staged installations due to fast-track and gettingon and/or laying the floorcovering too early before the adhesive or the setting materials have had a chance to effectively dry.
          *  Poor acclimazation or, worse yet, no acclimatization of the building during the ocnstruction and during the moisture testing process, leading ot potential dew point ocnditions at the concrete surface during installation. 
          *  Not appropriately protecting the concrte from the top (roof) and bottom (vapor barrier/retarder) allowing the concrte to be rewetted from the top and bottom resulting in moisture related issues even years after placement.
          *  Poorly-written specifications; misunderstanding, misapplication, and misinterpreation of recommended industry standards, guidelines, and procedures: incompatibility between CS Division 3 (concrete) and Division 9 (flooring) specification (e.g., flatness/levelness criteria).
          *  Poor communication between the members of the chanin of responsibility including, but not liminted to, the flooring and adhesive manufacturer, design professional, landscape designer, general contractor, concrete subconstractors, flooring installer, flooring maintainer, and owner.
          *  Various conflicting terminology, methods and recommendations used for quantitative and qualitative moisture testing.
          *  Lack of and incorrectly eecuted concrete pH and moisture testing.
          *  Installing a floor (although test results indicate different) that cannot - or should not - be installed due to elevated moisture vapor emission rate and/or pH levels.
          *  Potential of mold growth from concrete reltaed concerns and/or moisture intrusion into the building envelope.
          *  Not allowing for the proper expansion for products that change dimensionally due to thermodynamics and structural movement.
          *  Mixing dimensionally unstable flooring products together without honoring to contraction and expansion characteristics.
          *  Poor maintenance and/or lack of maintenance resulting in accidents.

Solutions
The solution to moisture-related problems begins at the design stage.  A clients' health, safety, and welfare must lead the design team to make every effort to make informed choices based on the most current and reliable information available.  Unfortunately, due to all of the real world problems, many decisions often end up being made soley on the basis of schedule or cost.  Statistically speaking, the cards do no favor such an approach and often lead to failures that end up costy many times more than what was thought to be saved. 

Here are a few tips to help make educated choices:
          *  Write the specification based on the most current industry documentation and guidelines.  Remember:  If these standards and guidelines are not written into the specificatino, even though the industry recognizeds them as being :applicable standards," your document will not be considered a complete specification.
          *  Do not rely on outdated specification resources.  Call to make sure you are using current data and applicable to the product you are going to specify.
          *  Thoroughly read and be sure you understand every standard and installation guideline before specifying a product in order to determine if it is applicable for that particular application.  Also, pay special attention to the kind of environmental and installation criteria needs that must be met before, during, and after the building process.
          *  When considering an alternative specification suggestion, make sure that you are comparing an apple to an apple.
          *  Use appropriate products for the type of applicatino and stage the job appropriately if a project is to be fast-tracked and value engineered due to cost and time.  Also, ask how much time are you really going to buy and what potential costly damage is risked by doing this fast-track procedure.  Where are the savings in the end?  It is not with eliminating something like a vapor barrier/retarder because your client just doesn't want to spend the money.
          *  Have the concrete tested for moisture and pH by an independent resource and/or laboratory in accordance with testing standards and applicable manufacturer's recommendations. 
          *  Ask the manufacturers questions such as; Do your products meet testing standards written by the industry? How were they met?
          *  If possible, get an installation and perfomrance history on products new to the market.
          *  Have all members of the chain of responsibility attend some of the design team meetings?  If so, consider the information they provide from their area of expertise.  If necessary, bring in an independent consultant who specializes in flooring, substrates and/or concrete.
          *  Be certain that the installers are appropriately certified, trained, and have verifiable years of experience.
          *  Understand the difference between floor FF/LL tolerances for concrete when compared to a straight edge measurement required of flooring.
          *  Protect the job site as much as possible.  Studies have shown that the vapor emission levels in concrete are affected by improper water/cement ratio, by rewetting of the concrete from rain, and/or lack of protection from beneath by a vapor barrier/retarder.
          *  Pay close attention to the concrete specifcation with regard to approrpriate water/cement ration, air content, unit weight, non-reactive aggregate, compressive strength, slab thickness, and surface finish.  Some floors may require different concrete finishes and a hard steel trowel finish may not be appropriate.  Also look at wet cure as an alternative to curing compounds and make sure to protect the concrte from rewetting as a result of rain.  Most importantly, for on- or above- grade slabs use a vapor barrier/retarder as specified in the ACI 3oz Index and following the ACI 3oz/26o specification documents.
          *  Consider using dehumidification and drying technologies as an alternative during the construction process.  Not only does this help with the drying of all the building products and significantly reduces the chance of mold growth, it also provides a comfortable productive work environment for the trades.  Dut to the various changes in materials, the drying process has changed for many setting products and, when placed in unacclimated environment with varying relative humidity and temperature (sitting at potential dew point), some products may never dry.  In these cases, floor failure and potential mold growth is virtualy inevitable.  Trafficking a floor too early can also cause products to debond and/or indent.  Also, it is much healtheir for the environment and HVAC unit to have it turned on for the first time after construction and after the subsequent dust has settled down.