A CPO and IPSSA member had contracted with a pool plasterer to re-plaster a swimming pool near Los Angeles. Within a week after plastering, the IPSSA member notified the plasterer that he could see some long cracks in several locations. The plasterer told the IPSSA member that the cracks would close and disappear in time. Two years later, the IPSSA member took these pictures of the quartz aggregate pool.
Note that the plaster coat has cracked and is delaminating away from the pool wall. When the plasterer was questioned about the obvious cracking and bonding problem with the new plaster, he suggested calling an independent plaster consultant who was also an NPC Board member to inspect the damaged pool plaster.
During his inspection, the consultant acknowledged the presence of a significant two foot-long plaster crack running down the wall and missing tile, but instead, focused on the signs of “etching and associated discoloration” of the plaster surface. The pool did have some smooth gray mottling discoloration in parts of the pool, but there were no signs of etching. The pictures seem to bear that out.
The consultant blamed the gray discoloration and (supposed) etching on the fact that the pool was filled with low calcium (80 ppm) tap water and that the water was not properly balanced at start-up. Yet, the IPSSA member had records showing that he added 20 lbs. of calcium increaser at start-up to raise the calcium hardness level to 200 ppm. The consultant refused to accept the IPSSA member’s account.
The consultant claimed that the (CYA adjusted) “carbonate” alkalinity was only 67 ppm, and the calcium hardness was 150 ppm, which he claimed were below national standards, making the water aggressive.
As a remedy, the plaster consultant recommended that the pool undergo a “Zero Alkalinity” process to clean up the etching and associated discoloration. Huh? Make the water extremely aggressive to clean up etching and discoloration which was caused by aggressive water? He also suggested “sealing” the cracks to stop the water leakage.
The consultant’s report states that he “saw no evidence of improper workmanship or materials with the plaster application.” The plasterer then refused to be held responsible for any issues with the pool.
About two months later, chunks of plaster began to fall off the pool wall. Because the IPSSA member was the remodeling contractor, performed the chemical start-up (Traditional), and had sub-contracted out the plastering, the pool owner demanded that the IPSSA member resolve the problem.
The IPSSA member paid out about $6,000 for another plasterer to re-plaster the pool. Samples of the old plaster were sent to a cement lab that determined the plaster surface was not etched. The plaster did contain 2.5 percent calcium chloride, which is known, along with late and overly hard troweling, to cause smooth gray mottling discoloration, which this pool apparently had. Of course, the major cracking and delamination was the more critical problem, but the consultant apparently felt otherwise.
The IPSSA member initiated a lawsuit against the plasterer, but became intimidated when an attorney, popular among plasterers in the area, threatened a counter lawsuit (frivolous and harassment).
It is alarming that without any supporting evidence or documentation, the NPC’s Technical Manual and other NPC literature suggests that slightly negative LSI water (-0.1 to -0.3) can cause spalling, flaking, cracking, white spotting or streaking, dark gray discolorations, and calcium nodules. (How does it decide which to do?) No, the NPIRC at Cal Poly has never proven anything remotely close to that.
Poor pool plaster workmanship practices continue to be enabled and protected by the NPC and their consultants.
Comments
Overall it is a rough job, Questions how thick was the plaster and what type I have written a very good (ONE EYED) article on Pool Refurbisment go to my website www.poolquartz.co.nz it can save you thousands and is based on different cases over the years.
I have had a good look at all the Photos.
Comments are this:
(1) Bloody rough Plastering.
(2) Tiles falling off poor addesive used also movement from the concrete poured coping will do this
(3) The crack the concrete shell would have to be suspect for this crack to appear maybe the pool build is a real cowboy and rode of with a bag of cash.
(4) The horizontal crack under the tile appears to look as if the pool has been built out of level and raised up with mortar and delaminated from the shell. again the builder is to blame.
Kiwi Norman
I suppose the consultant could have made a mistake, but that isn't what flagged me. The low CH number just seems way out of range for this area and caught my eye.
While I am not saying this is the case, if I learn how to do poor quality work from my Dad and then I go on to run the company, chances are I will continue to do poor quality work. The old saying "practice makes perfect" does not apply to continually practicing shoddy workmanship. That practice only perfects poor results. The fact that this pool has been re-plastered by another company with no issues seems to bear that out. Sounds like they finally found a good plasterer.
Maybe, the plaster consultant made a mistake on his testing of the calcium.
I am pretty sure the thickness of the plaster is the typical and sufficient half-inch.
You are right, the troweling workmanship is terrible as the one picture shows. The plastering company has been in business for many, many years. The owner learned the business from his father.
The pool has been re-plastered by another company. As far as I know, no problems since.
Interesting. I've never heard of 80 ppm calcium in fill water around here, even in San Bernardino.
I've always been lead to believe that water does not get aggressive until the calcium level gets below 75 ppm. 80 is pretty close, but not 75 (and I would tend to agree that it doesn't have anything to do with mottling or delamination.
From the pictures I also see a few things: Trowel work is awful; this is an established finisher? I see no float bed under the tile; it looks like they just spread thinset and stuck the tile to the wall. What is the thickness of the plaster? It looks much thicker than the typical 1/2" thickness.
This really looks like poor quality prep work followed up by poor workmanship to me. I see nothing here that screams a quality refinish job. My guess is there are more "failures" to come on this pool.
The pool is in San Bernardino county.
Yes, the calcium level of the tap water seems low, but that has nothing to do with and would not cause gray mottling discoloration or the delamination.
Also, if the fill water does have a low calcium content, by the time it fills the pool, the water will contain a higher calcium content because it will dissolve some calcium off the plaster surface. That is what it will do to newly finished pool plaster. I have seen the calcium go from 80 ppm to 120 ppm. Also, some of the calcium chloride added to the plaster mix also dissolves out of the hardened plaster and increases the calcium content of the pool water. (I wonder if this is taught in the NPC Start-up certification class?)
If (according to the NPC plaster consultant) filling a pool with low calcium water is so detrimental, why doesn't the consultant blame the plasterer for not adding calcium to the water while the pool is filling?
80 ppm calcium in Los Angeles water? I have to say that I have never heard of tap water in the south having that low of a calcium level.
I'd like to know what county that is in and who the water supplier is. Something doesn't sound right here.