By Randy Dukes
For decades, controversy has surrounded the initial interactions of water and cementitious finishes in pools and spas – controversy that has led to heated debate, bad blood, litigation and very little by way of resolution. But that hasn’t stopped numerous organizations and individuals from working toward an answer, says Randy Dukes, who discusses here an
approach to start-ups that represents the consensus of an array of experts and trade associations.
It’s an old, unfortunate history: For more than 20 years, the pool/spa industry has witnessed a conflict that has pitted plaster subcontractors against service technicians and put pool/spa builders in the uncomfortable position of not knowing which way to turn to deliver the quality interior finishes their clients demand.
The source of the conflict is any change in appearance of an interior cementitious finish that occurs after the watershape is filled with water: Whether it manifests itself as etching, staining, mottling, scaling, nodule formation, delaminating, cracking or crazing (among others), homeowners want somebody to fix things fast – and that usually means they want the disfigured material removed and replaced.
So the client calls the builder, who calls either the plaster subcontractor or the service technician – and whoever answers first immediately pins the blame on the other party, with the plasterer claiming that the pool’s chemistry has been improperly managed while the service technician will say that the surface material was inferior or improperly applied. All too often, these disputes remain unresolved until court proceedings are concluded.
The challenge here has always been the fabulous number of variables that come into play when water comes into initial contact with the plaster. There are always questions on the one hand about the quality and proportioning of the raw materials used in the plaster mix as well as the way it has been applied. On the other, there are questions about the nature of the feed water, water balance, testing protocols, treatment methods and a host of chemical factors including pH, calcium hardness, total alkalinity and total dissolved solids.
If you step back and look at that set of variables objectively, it’s small wonder that reaching a consensus on how to avoid problems has been hard to do.
A LONG, WINDING ROAD
For more than 20 years now, however, that consensus is precisely what a number of individuals and organizations have attempted to achieve. This has included not only the National Plasterers Council (with which I am affiliated), but also associations that represent service technician as well as raw materials suppliers, independent laboratories, trade groups, academic institutions, chemical manufacturers and others.
For years, these entities have wrangled with the issues and have tirelessly accumulated masses of reliable data in the process of developing appropriate recommendations and establishing valid standards. I’ve been one of the individuals involved in this process, and it’s been a fascinating and often frustrating ride. Along the way, I’ve examined thousands of pools, been part of countless meetings and discussions and, I am pleased to say, have played a part in our collective reaching of a reliable set of conclusions.
One of the areas in which we’ve made the most progress has to do with recommendations related to start-ups – that is, the procedures used when water is first added to a newly constructed pool or spa and a watershape actually becomes a watershape. Without question, this is one of the most important steps in determining the performance of the interior surface – the place where plasterers and service technicians come together.
It is important at this point to run through the official list of organizations that back this recommended procedure, as published by the National Plasterers Council. These include the Independent Pool & Spa Service Association (IPSSA) (which has included the document in the latest edition of its technical manual), the Association of Pool & Spa Professionals (APSP), the Portland Cement Association (PCA) and the American Concrete Institute (ACI).
For an issue as controversial as this, achieving that level of across-the-board endorsement is truly remarkable. Those of us who have been involved in the development of this start-up procedure believe that if it is used consistently and followed correctly, it will serve as a powerful tool in reducing plaster problems and all the headaches and legal and financial woes that come with them.
In looking at start-ups, we had to consider everything that was happening. We recognized immediately that the key was in the curing process, an amazingly complex set of chemical reactions that have a dramatic effect on the strength of the plaster. We also recognized the hazards involved in exposing that fragile, vulnerable material in intimate contact with large volumes of water, the universal solvent.
That’s not a desirable match, and experience of the past 20-plus years has shown it can become a living nightmare.
WATER AND CEMENT
In its role as the universal solvent, water always seeks mineral balance: If it contains too little by way of mineral content, it will seek it out and try to take it from any available source. In that state, which can be recognized by low-level readings for pH, total alkalinity and calcium hardness, water is said to be “corrosive.”
This spells trouble in the context of a freshly plastered pool, because the plaster features an abundance of soluble materials (such as calcium hydroxide) that are exactly what the water needs.
By the Index
The chemical processes taking place during start-ups are so complex that this article would have to be much longer to get the whole story out. In fact, whole books have been written on the subject, and anyone who has a deeper interest in the subject can easily find them.
For our more limited purposes here, what’s important to know is that, during the curing process, a number of reactions take place that, when allowed to occur slowly, will make the material stronger.
When plaster is applied, it is troweled on in such a way that the “cream” or fines of the material form an ultra-smooth surface. As this surface hydrates, it develops high levels of extremely soluble materials, such as calcium hydroxide, that gradually transition to become less soluble during the curing process. (For the most part, for example, calcium hydroxide will slowly transition to become calcium carbonate.)
While this transformation takes place, the surface is extremely vulnerable: The presence of water will either aid the process if it is balanced or exacerbate potential problems if it is either corrosive or scaling. This is why, during this interval, the primary goal is to maintain balanced water chemistry while also brushing the pool to remove calcium-rich dust from the surface.
Several chemical indices are used to determine water’s characteristics. In the case of the National Plasterers Council recommendations, start-up procedures are based on chemical parameters defined by the Langelier Saturation Index (LSI), which uses pH, total alkalinity and calcium hardness to generate a positive or negative value that indicates a scaling or corrosive environment.
The challenge with start-ups is that the fill water can vary wildly with respect to balance and will need to be treated in differing ways to generate an LSI-neutral value. What this means in practical terms is that, immediately after filling, the pool water’s balance should be adjusted to a pH level between 7.2 and 7.6; a total alkalinity of at least 80 parts per million and a calcium hardness ranging from 150 to 200 parts per million achieved in the course of the next 28 days. The procedure also recommends the (optional) use of a sequestering agent to help keep minerals suspended in the water while the balance is being adjusted.
The guidelines offer specific advice on making those adjustments. Copies can be downloaded from the NPC Web site (www.npconline.org), or a printed version can be obtained by calling the office at (866) 483-4672.
It’s worthwhile to note here that the recommended, LSI-based procedure recommended in the consensus report is not the only start-up approach now being used in the industry. For years, in fact, there have been substantive and sometimes ferocious debates about the fundamental nature of start-ups, with some people favoring procedures that generate a more basic water balance and others advocating low pH chemistries and acidic conditions. All of this discussion is well beyond the scope of this article.
When the water is balanced – that is, when the water is neither corrosive nor alkaline – it is a perfect companion for curing plaster by keeping it wetted and slowing down the curing process. This moderation of the curing process renders the plaster far more durable over the long haul.
Most of this curing process takes place in the first four weeks after the plaster is applied. By definition, this is what we now refer to as the start-up period. Working with builders, plasterers and service companies, we’ve found that by controlling water chemistry and maintaining close-to-neutral water conditions, the problems associated with curing plaster can be substantially reduced. (For more on the chemistry behind the recommendations, see the sidebar on page XX.)
As it stands, this curing interval should be familiar enough: We see similar issues with shotcrete or gunite shells and the conventional observance of a 28-day period during which the shell is hydrated in preparation for finish application. Through our partnership with experts at ACI, we learned that proper water-curing of concrete during this interval can increase concrete’s strength by 55 to 60 percent.
As a cementitious material, plaster is closely related to concrete, so it makes sense to infer that a water-curing procedure after installation will similarly increase the strength of a plaster finish.
While we consider that proper start-up procedures will reduce the number of finish failures and the aggravation that comes along with plaster problems, we also recognize, of course, that proper start-ups are not a cure-all: If there are gross errors in materials mixing or application – or if the service process is botched – the plaster can and will fail. Our point here is that good start-ups make properly applied plaster even better.
A SAFE INVESTMENT
The start-up procedure recommended by NPC and the rest of the endorsing organizations involves testing and adjusting the water chemistry and brushing the pool’s surface twice daily for the first 28 days. Somebody who knows what they’re doing has to perform these services – and this is where the industry as a whole needs to change the way it typically approaches the process.
At a basic level, the problem here is that many firms – builders, plasterers and service companies alike – aren’t thrilled by the prospect of following through with such a laborious, inconvenient regimen.
For all that, this is not something that should be ignored or left to the homeowner: If the builder does not include the start-up procedure as part of the construction package, then it’s his or her responsibility to communicate the importance of a good start-up procedure to the client, volunteer an approximate cost and, I believe, refer the client to a company that knows how to do start-ups and is prepared to provide the service. (To that end, NPC is currently developing a Certified Start-up Program for technicians.)
In other words, this is not something that can be left to the last moment. Instead, it should be viewed as part of the construction process and discussed with the homeowner as part of the overall project-management package. On that level, it’s all about giving the client every opportunity to protect a substantial investment.
Let’s consider the disposition of a homeowner who’s just spent $60,000 (or $600,000) on a backyard paradise and comes out a few days after the job has been completed to find a plaster surface that looks awful (if it’s white) and truly terrible (if it’s colored). Topping it all off, let’s assume that the expensive waterline tile – the homeowner’s pride and joy – is covered by a hard, milky-white deposit.
The Technician’s Role
As explained in the accompanying text, good start-ups are crucial to the performance of the interior surfaces of swimming pools and other plaster-lined watershapes: In practice, this step in delivering a finished product to the homeowner is accurately considered as both the end of the construction process and the beginning of the service process.
Most of these transitional procedures are performed by service technicians who either work directly for a builder or operate under contract. It’s my belief that these relationships should be revisited and that builders must take a more active role in ensuring that what happens when they turn a watershape over to a technician will serve the long-term interests of both the watershape and the client.
The way I see it, service technicians are custodians of our industry’s output, and increasing these days, that output can easily be described as a form of high art. These professionals maintain and protect the value of our clients’ investments, and to do so efficiently and effectively, they need to possess an array of knowledge as well as skills in working with chemistry, hydraulics, mechanics, electronics, masonry, plumbing and more.
They answer the call when things go wrong, and they rarely get the credit they deserve when everything works properly. If you’ll allow me to step onto a soapbox for a moment, it’s high time for designers and builders in the wateshaping industry to recognize service technicians for the professionals they are and the importance of the work they do.-- R.D.
Experience in these debates and in the field tells us that a proper start-up will dramatically reduce the chances of that sort of unpleasantness, and the ounce of prevention we’re recommending need not cost that much – perhaps $500 (or maybe more depending on the service company). By any measure, that’s a pittance compared to the potential damage caused by a lack of a proper start-up!
As someone who has looked at these issues for most of my adult life and have endured the debates and rancor for decades, I’ve come to believe in the recommendations offered by NPC are both effective and workable.
It’s also fair to point out that no one person or organization can claim primacy of authorship of this standard. While it is being issued through NPC, it represents the work of countless people, and the simple truth is that the chemical values advocated in the recommendations are widely known within the industry – especially among service technicians, many of whom doubtless will wonder what all the fuss is about because the procedures being advocated are so elementary and “back to basics.”
For my part, I’m simply glad we’ve found a procedure that has finally forged the elusive consensus we’ve been after for so many years and, more important, that it seems to be performing consistently in the field.
Ultimately, it’s all about making the industry’s clients happy. On that scale, the value of a good start-up is immeasurable, and a pool that contains a cementitious surface of any kind deserves to begin its life under the watchful eye of someone who knows a thing or three about the restless nature of water and concrete.
Randy Dukes is a consulting technical sales manager for Aquavations Corp., a manufacturer of pool-surfacing products based in Miami. Regarded among the foremost authorities on issues related to plaster deterioration, discoloration and staining, he has served as a continuing education instructor for the Florida Swimming Pool Association and Florida’s Construction Industry Licensing Board and has moderated and taught numerous courses for the National Plasterers Council (NPC), the Association of Pool & Spa Professionals and the NorthEast Spa & Pool Association. Dukes is a current member of the American Concrete Institute (ACI) as well as NPC’s Plaster Committee, Education Committee and board of directors and has spent extensive time traveling across the United States and Europe identifying pool surface problems and studying their relationship to application techniques, water chemistry and chemical abuse. Indeed, during the past 17 years, he has conducted and documented more than 12,000 of these poolside inspections, which led to publication of the book Pool Surfaces, Problems and Solutions, now in its seventh edition. He has also produced a poolowner DVD available through the National Plasterers’ Council called “Taking Care of Your Pool.”