All Plaster Finishes Should Last 20 Years

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
All pool plaster finishes should last 20 years or more. However, some last only 5 to 7 years, and some less than a year before the plaster surface deteriorates, discolors, and looks terrible.

Why the difference? Very often, plaster quality. As we have pointed out previously, studies on pool plaster and cement/concrete flatwork have shown that poor workmanship practices have the greatest effect on durability, deterioration and discolorations. Various studies also confirm that water chemistry plays only a minor role.

Fortunately, there are a lot of quality plasterers that understand the importance of proper plastering, and generally take an extra hour or two to properly plaster pools with good materials and good workmanship practices. Their pools usually last 20+ years.
However, there are some poor-quality plasterers that are in a hurry and use inferior and “short-cut” practices and/or materials to plaster quickly. Doing so allows them to underbid the quality plastering companies. Their pools usually last less than 5 years, and sometimes less than a year before the plaster problems begin. And when the plaster finish starts looking bad, they simply blame the water chemistry instead of their own sloppy workmanship. Sadly, they are enabled to do that by the NPC and APSP.

A “Pretend” Plastering Standard

A few years ago, the NPC and APSP got together to write an ANSI plaster standard. Unfortunately, they refused to mention and include important and critical workmanship requirements (well known by the cement and concrete industry) that would produce quality, durable, and discoloration-free plaster/cement finishes. No limits or standards at all!
Furthermore, the APSP/NPC standard doesn’t mention the defects, deteriorations, or discolorations that can result due to improper and inferior workmanship. That means there is no accountability for plasterers that do poor work. Sounds like a “protection” standard. Pool builders and State Contractor License Boards have little recourse to help pool owners.

What about Water Chemistry Standards?

On the other hand, APSP and NPC have very strict and narrow standards for pool water maintenance. Beyond that, their literature (incorrectly) suggests that if pool water is not maintained within their suggested water parameters, that plaster problems will result. No, in reality plaster studies show that slightly aggressive LSI (or CSI) water does not cause the defects or discolorations at issue.

The NPC and APSP should not be exaggerating and misusing the importance of proper water balance which leads to service techs and pool owners being incorrectly blamed for many different plaster problems.

Obviously, poor water chemical maintenance can result in uniform etching and/or scaling. Even some types of metal staining can be traced to chemical mismanagement. However, when plasterers attempt to associate spotting, streaking, mottling, discoloration of the paste, calcium nodules, spalling, etc. to water chemistry causes, you know there is no basis for that. They are factually known to be caused by improper materials, application or curing failures.

The Bottom Line

APSP and NPC should rewrite the ANSI Plaster standard and adopt applicable workmanship standards (similar to ACI and PCA standards) to promote durable and discoloration-free plaster finishes for pool owners. That would serve the industry much better and help prevent plaster problems occurring in the first place.

However, this ongoing travesty probably won’t change until the entire pool industry becomes informed of these issues, rejects the false claims that water balance is what causes the above plaster problems, and demands that the NPC and APSP make things right.

My father, who was in the plastering business 45 years ago, provided quality and discoloration-free pool plaster to their customers that lasted 20+ years.

Addendum:

When a plaster finish develops discoloration or defects, the following questions could be asked.
What does adding too much water, or too much calcium chloride (hardening accelerator), or performing too much water troweling, or overly late and excessive hard troweling do to plaster finishes?
And wouldn’t “tenting” pools (to overcome harsh weather conditions) and taking an extra hour help to produce a higher-quality plaster finish?

Those are important issues that are missing from the APSP/NPC/ANSI Plaster Standard.

The following links provide additional details regarding these issues.
A Plastering 'Watch List' | Professional Watershaping | Watershapes
Kim – Ten Steps to Durable and Discoloration-Free Plaster – Pool Help
 
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PoolguyinCT

In The Industry
Jul 21, 2014
3,083
Connecticut
Once a standard is codified it is everything but “pretend.”

- I believe periodic maintenance slated 2021?
Will you deliver the “50 pages” again, something new or abstain?
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
974
Utah
You know that some arm twisting, politics, and self-serving agendas were involved with that standard.
The bad plastering companies will like pretending that it is a credible standard and refer to it to builders, service techs, and pool owners when plaster discolorations and defects arise.

But the good plastering companies won’t use that standard because they perform quality workmanship that doesn’t develop discolorations or defects. They also know that there is nothing to learn from that standard about mixing and applying plaster. It is a hollow standard. I know some concrete/cement authorities and good plasterers that consider that standard a joke.

I will consider it a pretend and a protection standard until it contains appropriate limits on the amount of water (water/cement ratio) and calcium chloride that can be added to the plaster mix, limit water troweling and excessive late hard troweling and identify the effects of those issues.

Those are some of the workmanship and material issues that ACI and PCA authorities have long identified as determining the difference between producing durable and discoloration-free cement/plaster versus producing weak, defective, and discolored cement/plaster. A credible standard would include that information.

I hope you will oppose that standard (as currently written) when it goes through the revision process and propose some needed additions to it.
 

PoolguyinCT

In The Industry
Jul 21, 2014
3,083
Connecticut
We know the same fellows..

My comment was not pointed at practices, inclusions or exclusion or any particular standard.
Codified language is something we all live with, hence my words “not pretend.”