More plaster issues...

Rich D

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Bronze Supporter
Aug 3, 2018
1,086
MA
When opening the pool this spring I found small chips missing in my sun shelf and a few rough white spots on the sides of the pool. Most chipping seems to be around the In floor cleaning heads but there are some very obvious ones on the shelf itself. The pool tech that opened the pool said it was most likely from freezing on the shelf. This was not the same tech that closed the pool who drained the water below the shelf and placed a insulated tarp (frost blanket) on the shelf and instructed me to keep the water level below the shelf for the winter which is what I did. This is the same thing he did the previous year and there were no issues the following spring. It looks like there is also chipping around the In floor heads in the bottom of the pool but it is just too chilly right now to get in and check any of the bottom for additional chipping. The area under where the chips came out is a dark Grey plaster color.

Would there be any other cause for this chipping out except freezing?

In reference to the rough spots. I have read the reports on here from onBalance However it is not clear to me what these could be. From my understanding Calcium nodules will have more of a raised feeling to them. These spots look exactly like the rest of the white spotting that has occurred on my med Grey plaster. They are about 1-2" and irregular in shape. Running my hand over them they appear to be either flush with the pool wall or perhaps very slightly indented. I can scratch them with my fingernail and see small amount of dust come off of them. Could these be scaling? I found 3 of these spots on the areas of the sides I can reach down into the chilly water. I can not test any deeper until things warm up a bit and since they look like my white spotting it is impossible to tell how many I have. The the Pic shows what most of my plaster now look like. All of those white spots are smooth to the touch except a small 1"-2" patch which is rough.

The other terminology that is unclear to me is if 'White spotting' Is referencing the same affect as mottling.

The plaster company is supposed to be coming out in 2-3 weeks to check out these issues.

Any information on these issues would be greatly appreciated .. Thanks, Rich.





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Test Results 04-18-2019 @ 05:13 PM
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Free Chlorine: 5.0
Combined Chlorine: 0.0
pH: 7.6
Total Alkalinity: 75
Calcium Hardness: 250
CYA: 35
Temperature: 57°F
CSI: -0.38

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White spotting occurs when there was too much calcium chloride accelerant used in the plaster mix. Areas of the plaster where the calcium chloride concentration was too high look whitish colored compared to the bulk and has a more porous, mushy texture. Scale is deposits of calcium carbonate from the water. If the calcium is scaling from the water then it will be more of a uniform patch that may or may not be noticeably raised. You can usually remove it with brushing or by lowering the CSI of the water. Scale will often contain dirt and dust in it giving it an off white color. Mottling is a streakiness that develops in the plasters coloration and is the result of poor troweling and/or workmanship during the install. There’s really not a lot you can do about mottling as it is generally a colorant issue.

Be prepared to receive the standard response/causation from the plaster installer - pool owner negligence with respect to water chemistry. And their solution 99% of the time will be to drain and acid wash the pool which you will be expected to pay for.
 
Thank you very much for that clarification Matt. It was very helpful. Although still a bit fuzzy on the term 'Calcium nodules'. Is that considered scaling? The rough spots I have do not seem like they can be brushed off. If these areas were 'white spotting" would I be able to scratch them and create a dust?
It sounds like I have much more of a mottling issue then a white spotting issue. Most (but not all) of the discoloration can be seen as swirl marks from the toweling and of course the footprints in the deep end. There was one footprint last year now I have several. Although if the mottling continues it looks they they will simply be engulfed and masked by it :/ The footprints are far more noticeable then the picture shows. It is the one with the main drain in it.
Just for added clarification (if you can tell from pictures) would you say these pics show more mottling than white spotting? All the surfaces are the same smooth to the touch so I do not detect a "more porous, mushy texture".

Would you also say that this much mottling on a pool this new (plastered 9-13-2017) is normal?

Did you have any insight at all on the chipping? Still hoping to hear for some input on that issue as well.

Thanks, Rich

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Calcium nodules are caused by cracks in the plaster surface with voids between the plaster and gunite underneath. The water infiltrates the cracks and develops a really high pH and calcium concentration. Eventually the home fills up with calcium scale and erupts above the surface like a volcano. That’s what the “nodule” is, an eruption of calcium scale.

@onBalance will be the right person to diagnose your pool. To me, that looks like a very bad plastering job if it is only 2 years old. The mottling and troweling marks are excessive and it looks like you have pigmentation loss (bleaching) from possibly the use of non-color-fast organic dyes.

Sorry, but in my limited opinion, that plaster job looks terrible. If that’s a nationally known plaster brand like CLI or SGM or PebbleTec, I would be calling them in for an opinion on the installers work.
 
As for the spalling around the IFC, it is entirely possible that the stresses associated with the pop up head going off as well as the higher pressure and flow has just eroded and cracked the plaster in those areas. The plaster around the heads on the sun shelf certainly looks like it is chemically/physically damaged. Has acid been added to the skimmer and distributed via the in-floor system?

I’m not sure why they would drain the water off the shelf...that seems like a really bad practice to me. You certainly get deep freezing where you are but I would think the plaster would be safer submerged in pool water with a good solid cover over that area. Freeze damage will certainly cause plaster chipping and failure because any water absorbed by the exposed plaster can freeze and cause freeze/thaw cycling damage just like it does on exposed concrete.
 
Calcium nodules are caused by cracks in the plaster surface with voids between the plaster and gunite underneath. The water infiltrates the cracks and develops a really high pH and calcium concentration. Eventually the home fills up with calcium scale and erupts above the surface like a volcano. That’s what the “nodule” is, an eruption of calcium scale.

Thanks again for education..
@onBalance will be the right person to diagnose your pool. To me, that looks like a very bad plastering job if it is only 2 years old. The mottling and troweling marks are excessive and it looks like you have pigmentation loss (bleaching) from possibly the use of non-color-fast organic dyes.

Sorry, but in my limited opinion, that plaster job looks terrible. If that’s a nationally known plaster brand like CLI or SGM or PebbleTec, I would be calling them in for an opinion on the installers work.

Thanks for sharing your opinion. I have no idea what the plaster brand is. I do not even know the name of the plaster company. The PB has been handling my complaints so far. Last spring the plaster Co did send 2 service men out in a non lettered vehicle to check my complaints about the mottling and to fix the IFC head area damage from when they plastered over a head location in the initial plaster job and it did not blow out until the following spring. At that time they did suggest a acid bath However I did not pursue this because it just did not seem like it was a good idea to remove small a layer of plaster in a brand new pool for cosmetic reasons and it was also my understanding the issue would most likely return so I would have thinned my plaster for no reason.

So I am not sure where I could get the brand name of plaster used.
 
As for the spalling around the IFC, it is entirely possible that the stresses associated with the pop up head going off as well as the higher pressure and flow has just eroded and cracked the plaster in those areas. The plaster around the heads on the sun shelf certainly looks like it is chemically/physically damaged. Has acid been added to the skimmer and distributed via the in-floor system?

Nope.. I have always either poured it slowly along the deep end sides with the In floor system running as the PB originally instructed or recently I have been adding at the base of the flowing waterfall.
I’m not sure why they would drain the water off the shelf...that seems like a really bad practice to me. You certainly get deep freezing where you are but I would think the plaster would be safer submerged in pool water with a good solid cover over that area.

This particular tech (one of the PB long time top techs) said he had had issues with sunshelfs cracking and spalling when they just drained below skimmer. I Only have 12" of water on my shelf so even if they only take out 6" to get 3" below tile that will only leave 6" of water. I had 12" of ice on the pool last year so that would leave a solid block of ice on the shelf. So it did not sound like a bad idea at the time and of course I would go with whatever the company that is warranting the pool suggests.


Freeze damage will certainly cause plaster chipping and failure because any water absorbed by the exposed plaster can freeze and cause freeze/thaw cycling damage just like it does on exposed concrete.

That makes sense..

I thought perhaps leaving the 6" of water on the shelf then floating 4 or even 6" of ridged insulation cut to the shape of the shelf on top of shelf might be a good approach.. ¯\_(ツ)_/¯

In full disclosure the same tech recommend "not" covering the pool. Mostly because there was very little debris that would be getting in the pool and the difficulties of putting a cover on with all the boulders and waterfall as well as it would make things much easier for me to keep it drained below the shelf. He did all of the same procedures the previous year and there were no issues in the following spring. Again going with the warranting company's recommendation..
 
Well I guess you’ll just have to contact your PB for details. Normally the brand and type of plaster is specified in a build contract. If the contract just makes a generic statement about “a plaster finish with medium-grey color” then the PB is free to choose whatever materials he wants (usually the cheapest for him to acquire) and use whatever sub he wants for doing the job (again, his profit motive is to choose the cheapest installer). So, as long as the PB is willing to assume responsibility for the pool maintenance and surface warranty, I guess you’ll just have to follow up with them. There may come a point in the future where the PB decides its no longer in his interest to keep fielding the calls....

Again, just my honest and non-professional opinion but that plaster job looks lousy after two seasons and doesn’t speak well of the PB’s choice in materials or application. Short of tearing it and redoing it, I don’t see what can be done chemically to address the issues. As you say, acid washing is likely not going to fix the streaks and mottling of the color.

I understand your climate issues and it does make a plaster pool more difficult to close, but leaving plaster exposed to dry winter air and freezing temperatures is not the best idea. If the equipment is in an enclosure where it is safe from freezing, then I think you’d be better off leaving the pool full and running the pumps over the winter (with a light cover on the pool) to keep the water circulating to avoid freezing. Moving water doesn’t freeze as easily as stagnant water. But, if your equipment is unprotected, then you don’t have many options.
 

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Well I guess you’ll just have to contact your PB for details. Normally the brand and type of plaster is specified in a build contract. If the contract just makes a generic statement about “a plaster finish with medium-grey color” then the PB is free to choose whatever materials he wants (usually the cheapest for him to acquire) and use whatever sub he wants for doing the job (again, his profit motive is to choose the cheapest installer). So, as long as the PB is willing to assume responsibility for the pool maintenance and surface warranty, I guess you’ll just have to follow up with them. There may come a point in the future where the PB decides its no longer in his interest to keep fielding the calls....

Again, just my honest and non-professional opinion but that plaster job looks lousy after two seasons and doesn’t speak well of the PB’s choice in materials or application. Short of tearing it and redoing it, I don’t see what can be done chemically to address the issues. As you say, acid washing is likely not going to fix the streaks and mottling of the color.

I understand your climate issues and it does make a plaster pool more difficult to close, but leaving plaster exposed to dry winter air and freezing temperatures is not the best idea. If the equipment is in an enclosure where it is safe from freezing, then I think you’d be better off leaving the pool full and running the pumps over the winter (with a light cover on the pool) to keep the water circulating to avoid freezing. Moving water doesn’t freeze as easily as stagnant water. But, if your equipment is unprotected, then you don’t have many options.
I wanted to do this but with all the pipes in the frost line and not below the frost line they wouldn’t let me try it. I just really make sure I have too much water on a step or not at all so the water doesn’t freeze to the step. So if I get 2 inches of ice I make sure there is like 4 inches or water or none. That’s how I understood it from onbalance when I asked him. I’m just so careful of the ice in the winter and water levels. I check at least 1 time a week.

But like you said also I think that pool surface looks like it’s all molting. But I know way less than most people here still. I’m learning.
 
Well I guess you’ll just have to contact your PB for details. Normally the brand and type of plaster is specified in a build contract.

Just checked. It is not listed in contract.
If the contract just makes a generic statement about “a plaster finish with medium-grey color” then the PB is free to choose whatever materials he wants (usually the cheapest for him to acquire) and use whatever sub he wants for doing the job (again, his profit motive is to choose the cheapest installer). So, as long as the PB is willing to assume responsibility for the pool maintenance and surface warranty, I guess you’ll just have to follow up with them. There may come a point in the future where the PB decides its no longer in his interest to keep fielding the calls....

This is a reputable PB and has been in business for a long time. I certainly had a few issues with the build However so far the PB has stepped up and made things right. This spring has been extremely frustrating. To open my "Almost" new pool and find a 3.5' crack, chips off the sun shelf, more footprints, and a color that is quickly going from the med Grey which absolutely loved to a off white with a few Grey spots is heartbreaking...

After reading so many posts about such issues I feel the best I can hope for is a acid bath, after which my issues will most likely return and my plaster will have a shorter life. What kind of a "Fix" is that???

We were right on the fence about upgrading to a better surface, However the only options we were shown were pools with pebble tech with large Pebbles that were uncomfortable to walk on and we did not like the look of these either. The salesman told us that this plaster should last close to 20 yrs and forgot to mention anything about mottling. That part just boiled down to a terrible salesman.


I understand your climate issues and it does make a plaster pool more difficult to close, but leaving plaster exposed to dry winter air and freezing temperatures is not the best idea. If the equipment is in an enclosure where it is safe from freezing, then I think you’d be better off leaving the pool full and running the pumps over the winter (with a light cover on the pool) to keep the water circulating to avoid freezing. Moving water doesn’t freeze as easily as stagnant water. But, if your equipment is unprotected, then you don’t have many options.

Now that would be great if it were possible.. Unfortunately the wife, AKA 'Lucy Lightbulb' would never go for the whole power consumption thing. In addition we do get some lengthy cold snaps where even some of our swift moving rivers freeze over. Without heating the water ( no water heater yet) that could quickly turn into a nightmare...
 
I went through the same issues you are having. Just got my plaster removed and upgraded to a pebble tec (we paid for the upgrade).

OnBalance is the person you need to talk with. He helped me out tremendously and armed me with the info needed to have an educated conversation with my PB.

My resolution was a re-do of the plaster at no cost, or a discounted upgrade to the pebble. We went with the upgrade and are glad we did.

My original build thread is long. But the important info starts here. Feel free to PM me with specific questions.

New Pool - SE Pennsylvania

RC
 
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I went through the same issues you are having. Just got my plaster removed and upgraded to a pebble tec (we paid for the upgrade).
Wow.. Just read through your thread. Congrats on getting the new pebble tec. Our mottling certainly looks comparable but it looks like they had a parade in your pool. My foot prints are not as startling as those and I do not have any pics of plaster just before fill. Although I do have a fill line.
OnBalance is the person you need to talk with. He helped me out tremendously and armed me with the info needed to have an educated conversation with my PB.

Hopefully he will chime in on this one..

My original build thread is long. But the important info starts here. Feel free to PM me with specific questions.

Thanks for the generous offer.. I will most likely have some additional questions..
 
This plaster problem can be termed as a form of "mottling" - but I prefer to describe it and term it as "white spotting and streaking." It is very similar to the plaster problem which RC has chimed in about his own pool. It is often caused by excessive water troweling due to over-accelerating the hardening of the plaster with calcium chloride.

The discolored (whitish) plaster surface may still be smooth and hard because it has not been etched. White areas are more porous because of the loss of soluble plaster material (calcium hydroxide) and the grey pigment. I do not see any calcium scaling, including calcium nodules forming on cracks. The rough spots may be from minor delaminations or also known as "spalling" (thin layer flaking).

An acid wash or treatment would not remove the whitened discoloration (because the porosity and color loss goes deep), and of course shortens the life-span. But if they insist on trying to fix the color, then I think they would be "owning" the problem. So consider that.

I do not believe there is a non-colorfast issue with this plaster job, as evident by areas that are not discolored or whitened.
The freezing issues are unfortunate.
 
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Thank you for taking the time to clarify this for me. If I am going to push the issue with the PB and plaster Co I just want to be clear on the facts and terminologies. A few more questions if you don't mind..

- Matt had a interesting idea I have not seen in any of the posts I have read so far. This was to get the plaster manufacturer involved (If I can even figure out who they are). Do you think that could be helpful ?



The rough spots may be from minor delaminations or also known as "spalling" (thin layer flaking).

As noted above The water temp prohibits me from checking any deeper then an arms length (which of course would be the exposed area for the winter months) so I have no idea how many of these rough spots I have or if they are only within the draw down area.

- Is there a 'usual cause' for such spalling?
- could the "excessive water troweling due to over-accelerating the hardening of the plaster with calcium chloride" have contributed to this issue?

An acid wash or treatment would not remove the whitened discoloration (because the porosity and color loss goes deep), and of course shortens the life-span. But if they insist on trying to fix the color, then I think they would be "owning" the problem. So consider that.
Great point ..

The freezing issues are unfortunate.

-What would the typical 'fix' for this be and how does it affect the longevity of the plaster (IE are these now week spots subject the other terrible plaster issues?) I also have a thread going about the 3.5' crack that appeared this spring. So far all the PB is willing to do is 'V' it out-> patch and re-plaster the area. So any plaster repairs would most likely be done at that time.

- Could you give your opinion on 'not covering a pool for the winter in newengland' and how it might relate to some of my issues? As noted above the tech that has closed my pool (twice now) has recommended not covering. I have closed very late (early to mid nov) and opened very early ( first part of april) both times.

I would also be interested in any thoughts you might have on protection methods for the sun shelf. Now that the frost blanket idea has definitely been found to have faults. I can not imagine having 6" of ice on the shelf would be a great idea either? Although... I am sure there are plenty of other 12"deep sun selfs in NE and they can not all be flaking... ¯\_(ツ)_/¯

Thanks again... Rich.
 
If you didn't pick a special color and quartz product from a specialty manufacturing company, then the plaster material used is generic or standard cement, and with a generic color (grey) pigment added. If so, there would not be a representative to call for help.

When small and thin chips of plaster buckle off (spalling), it leaves the original plaster color exposed which is why those areas are darker in color.
If you have small and raised and white rough spots, then that would possibly indicate calcium nodules have formed where cracks have developed. But I am not sure you have indicated that that is something you have seen.
I quickly reviewed the pictures of cracks in your other post. I think that appears to be something that the PB will have to address too.
 
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