onBalance and NPC Plaster Guidelines

[DBissett]

I've been talking to PBs about doing our replaster (probably quartz) using the guidelines published by onBalance for the plaster mix and 4-6 hour delay for the fill, and getting pushback about the mix and the delay, and being told they follow NPC guidelines. I visited the NPC website this morning and read their bulletins but can't access the manual. So what are the NPC guidelines about the plaster mix? Are the onBalance guidelines much different?

About the fill timing, Technical Bulletin 2 - Hydration and Curing says "Interior cementitious finishes begin to hydrate during the mixing process with water. The new finish is cured by filling the pool with water after the surface has hardened to a point that it can be immersed". The recommended delay must be about waiting for the finish to harden, but does the manual say anything else that would support delaying the fill?

Thanks. I've found one PB that said he'd read the onBalance material and that's a good start, but knowing the NPC side of this might help our discussions.

 

[ajw22]

I don't think anyone here knows more about NPC Guidelines then @onBalance

It looks like you can buy the NATIONAL PLASTERERS COUNCIL TECHNICAL MANUAL - TENTH EDITION at https://www.npconline.org/store/ViewProduct.aspx?id=21480783

 

[DBissett]

I hope he joins in. I'm really just trying to find out if his plastering recommendations differ from NPC's and how. Maybe they're the same. I just don't know. I did find this statement in NPC's Technical Bulletin #5 about white cement...."Using CaCl2 as a set accelerator in amounts not exceeding 2% of the cementitious binder does not cause the finish coating to be weak or inferior, nor does it promote deterioration or surface etching of the swimming pool finish." onBalance echos that statement by recommending not over 2% CaCl2. The biggest pushback from plasterers seems to be the 6 hour delay for filling. I've read lots of PB websites and they all stress filling "immediately" after plastering, per NPC, but some say it's a problem to leave the pool empty for days due to cracking. There is no mention of hours. Is this a semantic issue? Does a 4-6 hour delay qualify as "immediate" when compared to days? I would think so. Anyway, I think the old white plaster finish we're replacing looks really bad and appears to have the problems that the onBalance methods are designed to eliminate, mainly significant etching of the surface and staining. The more I understand the better I can plan the job with the plasterers.

 

[JamesW]

You can become a Certified Start-up Technician by taking the Start-up Technician Certification Program.

Start-up Technician Certification Online Class | NPC

The Start-up Technician Certification Program is a National Plasterers Council initiative to set forth the proper protocol for a pool’s initial start-up.

www.nationalplastererscouncil.com

 

[bcre3306]

So there are no defined NPC guideline on how long from when the plaster process is completed until the filling of the water starts?

 

[DBissett]

I've not seen the NPC manual but most instruction articles I've read all say "immediately", which I think just gets repeated over and over. OTOH, I've read articles that say you're not supposed to wait DAYS to fill the pool because that would damage the plaster. So I think it boils down to the definition of "immediately". According to OnBalance waiting a few hours is good for the plaster and won't damage it at all. While maybe not strictly immediate, it's immediate enough. That's what I did and it turned out well. A word of caution though. During the fill, which took about 35 hours, I had a small leak from a return jet and that caused a very noticeable stain running about 10 ft in the near white plaster. Spoiled an otherwise beautiful job. Might do a partial drain and acid wash that stain out next year.