New plaster on renovated pool- when to refill?

door_man

Member
Apr 17, 2019
6
Dallas, Texas
A pool company is coming in tomorrow to RE-RE-plaster a pool after doing a subpar job the first time, and after that experience, I decided I should probably avoid trusting them as much as I did the first time. After doing some research I asked that they wait six hours to start the adding water, which they very vocally disagreed with. They also were not able to tell me industry standards for mixes of the plaster, which also raised some red flags for me. Unfortunately, I'm stuck with them at this point (since they're already having to redo the job). I feel like my best bet is to try and babysit as much as possible to try and avoid any more issues.

I've read some resources online that strongly recommend waiting at LEAST six hours to start refilling a replastered pool, but other resources (and the contractor I'm using) adamantly demand they begin the filling process immediately.

Both sides claim that "their way" prevents potential long term defects. Does anyone have any advice on this? I'm extremely skeptical of the NPC's guidelines, especially since a lot of people think they have the interests of the service provider in mind and not the consumer. I was hoping for some less controversial resources on the subject, or maybe something more definitive.
 

Geebot

Well-known member
Aug 19, 2013
895
FWIW our pool guy started filling as soon as they were done plastering with the goal of filling the plastered surfaces as soon as possible..
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,422
Laughlin, NV
Right- one says to wait, the other says to refill immediately. The resources conflict similar to other resources I've already looked up.
One says to wait 6 hours. The other is saying to fill as quickly as possible once you start to fill. It says nothing about the wait time as that is normally dictated by the plaster company.
 

door_man

Member
Apr 17, 2019
6
Dallas, Texas
One says to wait 6 hours. The other is saying to fill as quickly as possible once you start to fill. It says nothing about the wait time as that is normally dictated by the plaster company.
It actually just says "fill the pool as quickly as possible" and does not mention "once you start to fill." To me this implies that the fill should be started as soon as plastering is done.

I feel like I'm losing you at some point. If you read the original post, I said there is conflicting information. The article you've linked to says to wait at least 6 hours. My pool company says to fill immediately. You've reposted an article I've previously read that says to wait at least six hours, but also told me to listen to the pool company (which says to fill immediately). I feel like this advice is a bit contradictory.

Like I said in my original post, there is conflicting information out there, and I'm wondering whether any experts or anyone with firsthand experience has strong opinions about it one way or another.
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
976
Utah
Here is the research and results on the topic of filling new plaster pools.

If you can try to get them to compromise and perhaps get them to allow you to start the water at the 2 hours point, that would be better than nothing. Also, only the bottom bowl of the pool is affected by the early water submersion. Also, hopefully the tap water is not aggressive (soft). If soft, talk them into compounding the water with sodium bicarbonate (Bicarb Start-up) as it fills. I hope you can teach them something.
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
976
Utah
A warranty from a company that doesn't understand "cause and effect" of poor practices isn't worth very much, especially if they then simply blame most plaster defects and discolorations on the water balance if something goes wrong.

Since I know the amount of damage (dissolution) to a plaster finish from being submerged in water too early, a few years ago I explained to a pool contractor that I would take responsibility for waiting a few hours to fill my new plaster pool in order to protect the bottom bowl. Of course, I also told the PB that if something went wrong with the plaster finish, that he would have to prove that waiting a few hours to fill resulted in the plaster problem occurring. And that since the shallow end steps and walls aren't submerged in water for at least 24 to 36 hours, that he would have to show the correlation between that and the plaster defect or discoloration developing somewhere else in the pool.

In other words, I would take my chances in court if necessary because there are a number of things involving known poor workmanship practices that result in defects and/or discolorations which would have no connection to waiting a few hours to start filling the pool. I believe the contractor would have to prove a "cause and effect" for waiting a few hours to fill to whatever damage that occurred. Fortunately, more and more plaster companies are changing their policy in regards to this "fill-delay" issue and would testify concerning that.

Lastly, if the weather is very hot and dry during the plastering and filling, a good contractor would "tent" the pool to protect the walls and shallow-end floor and steps from the sun and dry heat while it fills for 24 to 48 hours.
 

lasvegaspools

In The Industry
Jan 19, 2015
120
las vegas
I understand that you have your research to back your side, most contractors use NPC to back them. As far as I can tell neither side has proved the other side to be 100% at fault for the numerous issues that can arise with the pool plaster. In court the customer would have to prove the contractor at fault not the contractor prove the delayed fill was the problem. Therefore the default should be to follow whomever is providing the warranty.
 
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jeffr47

Bronze Supporter
Oct 19, 2018
105
Rockville, MD
We had the same debate. Pool company said to fill asap, and in the end we decided to go with that advice since they are providing the warranty. For whatever it's worth at this stage, it all seems to be fine (a few months out)...
 

jeffr47

Bronze Supporter
Oct 19, 2018
105
Rockville, MD
Since I know the amount of damage (dissolution) to a plaster finish from being submerged in water too early, a few years ago I explained to a pool contractor that I would take responsibility for waiting a few hours to fill my new plaster pool in order to protect the bottom bowl. Of course, I also told the PB that if something went wrong with the plaster finish, that he would have to prove that waiting a few hours to fill resulted in the plaster problem occurring. And that since the shallow end steps and walls aren't submerged in water for at least 24 to 36 hours, that he would have to show the correlation between that and the plaster defect or discoloration developing somewhere else in the pool.
Unfortunately I don't think this is realistic in a court. You'd be stuck convincing a court that despite the contractor saying "we advised A, customer did B, and now complains about the result", the contractor is still responsible. Not a bet I'd like to take!
 

onBalance

TFP Expert
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In The Industry
Jul 25, 2011
976
Utah
This pool in question above has probably already been plastered and filled with water, so this discussion is taking place after the fact. But to help others that may read this thread, I submit the following information.

Topic 1: Cement products need a certain amount of time to harden before being submerged in water, because it is very easy to dissolve the surface of fresh unhardened or uncured cement/plaster. I don’t see how anyone can disagree with that. In fact, the NPC's own plaster tests (Cal Poly-NPIRC) provided evidence and results of that fact. Therefore, shouldn’t homeowners try to request waiting a few hours before starting the water and reaching an agreement regarding the warranty?

It is fortunate that many plaster jobs are not done so quickly as to cause a tremendous amount of plaster dissolution damage to the bottom bowl of the pool due to early filling. However, if that does occur, the homeowner would still have to prove that in court. So what good is a warranty with uniformed plasterers? Your plaster now looks terrible and you followed their advice? They will still blame the water chemistry for the problem, and will you win in court? Please consider that the remedy (acid treatments or torching) for fixing the problem usually makes things far worse than otherwise. The plaster surface has been compromised, and good luck trying to make it look good and last for 20 years, which is typical for good original plaster jobs. That fact is what I think is not being considered regarding this situation. And that is why I would chose a different course. But everyone has a right to their own perspective and priorities.

Topic 2: There are also other poor workmanship practices that cause other types of plaster defects and discolorations. I have addressed those issues in other posts that I have written for the TFP forum which can be looked up.

It has been suggested that the NPC will defend plasterers. That part is true, at least at first with simple claims and theories. But without proof. Let’s be clear, the NPC cannot (and do not) point out within any of their reports of test pool experiments that proves their contention that poor water chemistry is at fault for causing gray mottling discoloration, calcium nodules, delamination, flaking (spalling), cracking, color loss, or white soft spotting.

On the other hand, aggressive water will cause uniform etching, and high hardness water will cause uniform scaling.

The amazing thing is that the NPC’s test pool (NPIRC) reports are being hidden. The NPC has a written a short summary on their experiments, but they don’t include the hard data and comparative charts. Why? I suggest they know that the full reports don’t prove what they have been claiming and do prove that improper plastering is the likely cause.

The NPC cannot site American Concrete Institute or Portland Cement Association literature to back up their claims that aggressive water causes those plaster defects. Cement/concrete products are subjective to (aggressive) rain all the time and do not result with similar defects when proper workmanship is followed. ACI and PCA literature and documented studies do point to improper practices that do cause concrete defects and discolorations similar to what occurs in plaster pools.

When a homeowner obtains and uses the above information as a defense or offense, it has been my experience that the NPC backs off, and then the plaster company usually agrees to take responsibility for the plaster problem. They don't want to lose in court.

So, no court trial or appearance is necessary, and that is a good thing.
 
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MinerJason

Bronze Supporter
Jan 29, 2018
269
Tucson, AZ
I'm somewhat clueless when it comes to pools and pool construction, but I do design, quality control, and strength testing of cementitious products as part of my job. For these reasons, I know a lot ways to make sure cementitious products like plaster end up as strong as possible, and a lot of ways they can be screwed up. When interviewing plaster companies I asked a lot of pointed questions in an attempt to find one that would do things the correct way and still provide a decent warranty. The guy I settled on was slightly nervous about waiting 6 hrs to fill due to previous complaints about small shrinkage cracks developing when filling was delayed on a couple of jobs. He usually waits 3-4 hours before starting the fill because of this. I explained that if he's getting shrinkage cracks when waiting 6 hrs, his plaster mix is too wet and/or the curing conditions aren't being controlled properly, both of which would also make the finish significantly weaker in the end on top of increasing the risk of shrinkage cracks. After a long discussion he agreed to a low water to cement ratio and a 6 hr minimum wait prior to filling, and I agreed to fog/mist the finish after application and before filling.

In the end we decided to go with a pebble finish which my plaster guy waits 24 hrs to fill so in some ways it became a non-issue. I still insisted on a low water to cement ratio, minimal use of calcium chloride, water to expose the aggregate instead of acid, and I fogged it every few hours all day while it was curing. I also convinced him to allow me to use the bicarb start-up method with no impact to the warranty.
 
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MinerJason

Bronze Supporter
Jan 29, 2018
269
Tucson, AZ
The amazing thing is that the NPC’s test pool (NPIRC) reports are being hidden. The NPC has a written a short summary on their experiments, but they don’t include the hard data and comparative charts. Why? I suggest they know that the full reports don’t prove what they have been claiming and do prove that improper plastering is the likely cause.

The NPC cannot site American Concrete Institute or Portland Cement Association literature to back up their claims that aggressive water causes those plaster defects. Cement/concrete products are subjective to (aggressive) rain all the time and do not result with similar defects when proper workmanship is followed. ACI and PCA literature and documented studies do point to improper practices that do cause concrete defects and discolorations similar to what occurs in plaster pools.
I'm pretty familiar with the ACI literature, as well as most ASTM standards relating to curing and testing of cementitious products, and was a bit shocked when I started researching the NPC's stance on some things. Many of the defects they imply are caused by aggressive water chemistry are either in direct conflict with the literature I'm familiar with, or would only apply to aggressive water chemistry during and shortly after the fill.
 
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CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
I'm pretty familiar with the ACI literature, as well as most ASTM standards relating to curing and testing of cementitious products, and was a bit shocked when I started researching the NPC's stance on some things. Many of the defects they imply are caused by aggressive water chemistry are either in direct conflict with the literature I'm familiar with, or would only apply to aggressive water chemistry during and shortly after the fill.
Exactly... spot on...
 

CaveDiver1932

Well-known member
Mar 2, 2014
98
Dallas
I agreed to fog/mist the finish after application and before filling.
I have often wondered about misting etc. Years ago this was recommended but not so any longer. In AZ, could this lead to more expansion and contraction of the surface over and over?

In the end we decided to go with a pebble finish which my plaster guy waits 24 hrs to fill so in some ways it became a non-issue. I still insisted on a low water to cement ratio, minimal use of calcium chloride
That should be standard even with NPC now. Something I believe the NPC agrees.

water to expose the aggregate instead of acid
Water is the standard to expose the aggregate. I believe the light acid wash is part of the cleanup process. It does beg the question of exposing aggressive water during the curing process though.
 

jeffr47

Bronze Supporter
Oct 19, 2018
105
Rockville, MD
So much unnecessary voodoo. 😖 It's almost like these companies don't understand the actual process of what they do, they just have some anecdotal experience of it working a particular way in the past and so they cling to that like a religion.
 

MinerJason

Bronze Supporter
Jan 29, 2018
269
Tucson, AZ
I have often wondered about misting etc. Years ago this was recommended but not so any longer. In AZ, could this lead to more expansion and contraction of the surface over and over?
Without misting it's just a continuous plastic shrinkage (contraction) happening. Misting will stop the shrinkage, or at the very least pause it each time it's done if it's not done continuously. Shouldn't be much expansion going on when it's misted.

The real reasons to do it though are to reduce temperature, help keep the moisture content more even throughout (reduces differential curing which can also contribute to shrinkage cracks), and most importantly to provide ample water for the hydration process which leads to more early calcium silicate growth to add strength and fill in the pores.

Water is the standard to expose the aggregate. I believe the light acid wash is part of the cleanup process. It does beg the question of exposing aggressive water during the curing process though.
It certainly should be, but that's not always the case. Several of the plaster companies around here use a pretty strong acid solution to remove the cream layer and expose the aggregate the next day rather than troweling/rinsing it off during and immediately after the application.

Aggressive water is only an issue if there's a high volume of it in relation to the surface area of the cementitious product (like filling a freshly plastered pool). Concrete slabs are often water cured for 7 days by building a dam on the forms around the slab and flooding it with an inch or two of water. The volume of water in relation to the surface of the concrete is small enough that even if it's aggressive water to start with, a relatively minute amount of calcium leaches out and immediately flips the chemistry such that it has a very high LSI. The minute amount of calcium leached out is way more than made up for by the benefit of a wet cure, and will result in a much harder, stronger, and less porous surface than if it were dry cured. Large volumes of aggressive water early in the cure on the other hand can leach out significant amounts of calcium leading to a weaker and more porous surface, as shown by the experiments performed by @onBalance

So much unnecessary voodoo. 😖 It's almost like these companies don't understand the actual process of what they do, they just have some anecdotal experience of it working a particular way in the past and so they cling to that like a religion.
Yep. Talked to the guy who does all the start ups for the plaster company I used, and a lot of the things they did certain ways "because that's the way we've always done it and it's always worked".
 
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