Remove old plaster or sand blast?

[goofiness]

We're getting bids now to do some renovation on our pool, built in 1978. Original deck is exposed aggregate, the stones are falling out, and the deck has many cracks. Fairly straightforward, going with a smooth finish.

We've had it replastered twice, last time in 2007. The plaster has one tiny hairline crack that was filled with some epoxy, and does not seem to leak. It has some staining on the side walls, maybe from mustard algae. Both redos removed the old plaster. The first contractor this time said that they sand blast the plaster, except for areas around returns and if there are cracks. We will probably go with some sort of "pebbled" surface this time.

Any opinions about simply sandblasting rather than chipping off the old plaster?

Thanks.

 

[ajw22]

Not chipping out the plaster increases the risk of delamination. Only someone onsite can assess the condition of your existing plaster. In some areas putting a second layer of plaster on is the usual procedure. Ususally it works out fine but problems can occur.

You have to decide if the savings are worth the risk.

 

[JoyfulNoise]

My preference is for full removal of the old plaster. Sand blasting is only going to make skim coat of the new plaster stick to the old plaster. If the old plaster is compromised in its bonding to the shell, then you’ve basically put good material on a bad substrate.

Would you have a classic car simply “painted over” without removing the old paint and rust first?

Question is - is this your “forever home”? Do you plan to have a Viking Funeral in your pool when you die? If so, then have the job done right.

 

[lasvegaspools]

Sandblasting, chipping out, hydro jetting is usually done based on the specific job and the equipment of the contractor. Very few contractors have the equipment to sandblast, and even fewer have the equipment to hydro jet. This has led to the chip out becoming the default method for large parts of the country. Chipping out will work on almost any pool since it removes the existing plaster. Sand blasting can work just as well as chipping out depending on the existing surface and use of bondcoats. Depending on the size of the machine hydro jetting can also work on most jobs. The key is a properly prepared surface prior to new plaster application.

 

[goofiness]

Thanks for the replies. The "boss" has not been out yet. The young man who did the measurements mentioned sand blasting, which I had never heard of, and certainly not on the prior re-plastering. Except for the straky stains on one of the sidewalls, and the hairline crack, there are no other "issues". No blistering or peeling. I'm a little concerned about the stains bleeding through new plaster, if not chipped out. I've no idea yet, what the cost would be for one process or the other. We are in our mid-70's and plan to be here until we can't.

I also have questions about the new surface, and a leak, but guess I should start new threads.

Thanks, again for opinions on preparation.

 

[goofiness]

Our pool was built in 1978. Toward end of August I noticed I was adding more water than usual. By mid-September I was pretty sure, and started bucket test. No wet spots along any visible surface above the pipes. With normal pump run of around 8 hrs, including booster pump for pool sweep, it's losing around 1/2" per day. Doesn't change with solar plumbing open or closed. With solar active, there are usually "champagne bubbles" from two return inlets, none with solar off. With pump completely off, loss is about 1/8" per day, same as the bucket. There is a 4' vertical hiarline crack, about 5 yrs old, sealed with epoxy, no apparent change.

So, I believe the leak is in the plumbing, probably under the pool deck, close to where the lines from the pump/filter get close to the pool. I have had terrible experience with two leak detection companies in the past. Both times, they broke the main manifold around the pump/filter, blaming it on "brittle" pipes, and leaving me to do the repair. My thought is to have the pool contractor fix the leak when the deck is removed. Simple. But, then I thought, what if its from the bottom drain or something similar? Can they do leak tests on plumbing with the pool empty?

Thanks for any insight.

 

[ajw22]

I also have questions about the new surface, and a leak, but guess I should start new threads.

Keep all of your questions about a project like a replaster in one thread. It helps us keep the entire context of what you are doing.

 

[ajw22]

But, then I thought, what if its from the bottom drain or something similar? Can they do leak tests on plumbing with the pool empty?

Depending on how your plumbing is done they can plug pipes and pressurize the pipes to test for leaks with the pool empty. Someone needs to study your plumbing and develop a plan for how best to pressurize selective pipes.

 

[goofiness]

Thanks. That's what the last two "leak detectors" were doing when they trashed the manifold. They disconnected pipes, attached heavy fittings to the end of the unsupprted pipes to pressurize them, and bang! Everything on the ground.

I think a potential problem is with the suction lines. One line drains both skimmers into one pipe before entering the filter. The other drains the bottom drain into another pipe. Both had shutoff valves when installed, but I think both are frozen, and cannot be shut off. It's reassuring to know it can be tested with pool empty. I wasn't present when the pool was built, but I imagine they must test the plumbing before filling it up.

Should I try to get a "leak detection" outfit to evaluate, or leave it up to the pool contractor? I think some are more into testing than others.

Thanks again for your comment.

 

[goofiness]

Keep all of your questions about a project like a replaster in one thread. It helps us keep the entire context of what you are doing.

Sorry, I already posted a new thread about leak detection/management. (Merged threads - TFP Mod)

Next question has to do with the new material. I've had plain, basic white plaster. Now I'm thinking about color and texture, which my neighbors have. The first pool contractor mentions three choices: plaster, PebbleTec or ?quartz. One neighbor has a pebble surface, which he says is sort of rough underfoot, but doesn't mind. The other neighbor got what he thinks is some kind of pebbled surface that was ground to a smooth finish (? maybe Primera Stone). Now that we have so many tall shade trees our solar pool panels are not so effective, and I'm thinking a darker color might get warmer.

I know price is a factor, but I'm also concerned about being able to see problems, like algae, with darker, textured surfaces. Thoughts on options?

 

[ajw22]

If you wait until you can see algae you are not doing good water chemistry. You should be identifying if you have an algae problem before algae is visible by excessive chlorine consumption and the Overnight Chlorine Loss Test.

Dark surfaces are more prone to mottling and color variations. If you are picky about having a uniform color then stay with lighter colors.

 

[ajw22]

Thanks. That's what the last two "leak detectors" were doing when they trashed the manifold. They disconnected pipes, attached heavy fittings to the end of the unsupprted pipes to pressurize them, and bang! Everything on the ground.

I think a potential problem is with the suction lines. One line drains both skimmers into one pipe before entering the filter. The other drains the bottom drain into another pipe. Both had shutoff valves when installed, but I think both are frozen, and cannot be shut off. It's reassuring to know it can be tested with pool empty. I wasn't present when the pool was built, but I imagine they must test the plumbing before filling it up.

Should I try to get a "leak detection" outfit to evaluate, or leave it up to the pool contractor? I think some are more into testing than others.

Thanks again for your comment.

The suns UV weakens PVC which is why PVC pipes are painted in sunny areas. If your pipes fail the pressurization test then they probably needed to be replaced. The leak test did its job, unfortunately leaving you with the repair. Many leak test companies just find the leaks and don’t repair them.

Pool builder or Leak Test company label doesn’t make a difference. You have to talk with the companies and determine who seems to have the best expertise and plan to tackle your problem. It is about the specific people you get on site versus the company.

 

[goofiness]

If you wait until you can see algae you are not doing good water chemistry. You should be identifying if you have an algae problem before algae is visible by excessive chlorine consumption and the Overnight Chlorine Loss Test.

I think I do an excellent job of testing, and recording, on a daily basis during run-up early season, then backing off when weather, sun exposure stabilize. I have Excel data going back to 2012. Until I finally realized that the stains on the side of my pool were yellow algae, I had to up the ante, raising chlorine levels, and testing even more often. But thanks for the reminder.

Pool builder or Leak Test company label doesn’t make a difference. You have to talk with the companies and determine who seems to have the best expertise and plan to tackle your problem. It is about the specific people you get on site versus the company.

Right. In our area, the biggest problem is getting someone on site in the first place. Actually, that's the second biggest; first is figuring out who's got a good track record. It's a roll of the dice. The people that did the last tile/plaster had a good reputation. The re-plaster looked awful from the the start, and they ended up redoing it.