Newish Concrete Patio Creating Cement Dust - is this normal?

[dd27]

We had a new in ground pool built spring 2013 and there is approximately 1,000 SF of concrete decking that was installed at the same time (late May 2013 on patio). For the past two seasons we've noticed that cement dust in getting on our feet and in the pool. At first we thought maybe the pool water was evaporating on the deck and leaving a salt residue. We first noticed the dust on our feet as we were leaving foot prints on the wooden deck steps after leaving the patio. Then we started noticing the gray cement dust clogging the filter cartridges and ultimately collecting in the deep end near the drain.

When inquiring with the master pool builder (which by the way has not helped in the least with anything) stated that they have never seen this in 60 years of pool construction. When the concrete contractor met us in person to look at the decking, he said this is completely normal and only lasts a few years until the top layer wears down. Contradicting stories led us to our own research. All three independent concrete contractors and testing/inspection folks we spoke to suggested that the concrete was finished too soon while still too wet. Consequently, our concrete contractor suggested a heavy power washing to fix the problem. When they came to power wash, they casually mentioned that they would be back after the weekend to seal with Ardex Concrete Guard.

So finally, my questions:
1) Has anyone else had excessive "dusting" from a new concrete patio? If so, how was the problem cured?

2) Is there an effective way to restore the cartridges that are severely clogged with cement dust?

3) Has anyone used Ardex CG? We are not interested in changing the appearance of the patio and don't want it to look constantly wet or shiny. Anything I find online leads me to believe it is a clear gloss and will be shiny.

Thanks!

 

[zethacat]

I'm far from an expert on the matter but based on your location I believe your concrete should have been sealed from the get-go since you have a SWG, and you should be re-sealing it yearly. You can try soaking the cartridges in a 1/5 MA solution. Here is a helpful thread on Concrete Sealers. I am guessing it was never sealed since you say you have had this problem for 2 seasons and since your pool was built in spring of 2013, that's pretty much since day 1. Correct me if I'm wrong about that.

 

[dd27]

Thanks. Never sealed and the builder and concrete contractor said they never seal concrete decks. We spoke to several pool owners and none of them had their sealed either. When the concrete contractor came to inspect the problem, they actually said NO to sealer when I suggested it. Now they are planning to seal without advising us first, which is worrisome.

Thanks for the insights. We'll try the 1/5 MA soak. How long? Overnight? We've already suggested that they need to replace our filters based on the problem and I will continue to pursue so until we are satisfied. We did use filter cleaner earlier in the season, which helped, but not much.

 

[zethacat]

I agree that is worrisome and that they should replace your cartridges.

From what I understand they should be soaked in dishwasher detergent before you acid wash them (which I believe is an overnight process). Check out this thread:

http://www.troublefreepool.com/threads/4224-Re-How-to-clean-a-cartridge-filter

"WARNING: Failure to remove all oils and cleaning solution before acid soaking will result in a permanent restriction of water flow and cause premature cartridge failure."

 

[Divin Dave]

a bit of concrete dusting is not unusual, depending on the concrte mix. If it was a bit "soupy" there definitely will be excessive chalking for quite a while. Also, they may have used some calcium chloride as a curing agent or acceelerator. CC is used when cold temps are expected during concrete work. Calcium Chloride will definitely give it a chalky dusting on top for years unless it's sealed. Every time it rains and then drys out, Calcium Chloride will hydrate to the top of the concrete.

Im not saying your concrete contractor doesnt know what he's doing, but him telling you not to seal concrete or they never seal concrete is utterly preposterous! That just boggles my mind.

Sealing concrete is generally a good idea. It will prevent staining from anything liquid that is spilled on it, bird poop stains, vegetation deterioration stains, rust stains caused by iron in fertilizers and all sorts of other staining stuff. It will keep your concrete looking good. Reapplication ever couple of years will do it.
If you dont seal it and it gets stained, then its very difficult if not impossible to get the stains out of the concrete. No matter how hard you try, you cannot preven unsealed concrete from eventually getting stains and over a period of time, it will become unattractive.

Concrete sealer can be had in a natural or flat finish, satin and glossy finishes. The natural or flat does not give a wet or shiny apperance. If you have smooth or broom finished concrete, seriously consider adding some non-skid additive to the sealer. Any smooth finished concrete will be very slippery when it gets wet.

Power Washing alone may get rid of the chalking. If not, do a muriatic acid wash. You can google how to do a MA wash. You just leave the MA on long enough for it to stop bubbling then scrub scrub scrub with a stiff broom, then wash it away with water. Do a small section at a time. When done, sprinkle soda ash all over so as to deactivate the MA, then wash the soda ash away with water.

Dont leave the MA on any longer than you have to (30 mins or less). The MA dissolves the concrete paste and the aggragate within the concrete can become loose and dislodge from the concrete.

Cant help with how to restore your filter. Sorry.

Not familiar with the specific brand your concrete guy mentions. There are lots of good brands out there though. Concrete sealers are either solvent based or water based. Solvent based are the best but have a strong odor for a day or so after application. They are the easiest to initially apply and also re-seal over also when its time for reapplication. Since its solvent based, if you have to reapply an imperfect spot or two, the solvent just dissolves the sealer on the bad spot and it all blends back together. Same goes for reapplication.

Water based sealers IMO are more difficult to get perfect. Any air bubbles can be visible and if there is any moisture on the concrete when water based sealer is applied, can leave a milky appearance when dry.
Since its water based, simply applying more sealer over the bad spot doesnt do anything to speak of. The bad spots in the sealer will have to be removed by hand, then reapply.

As a FYI, never try to reapply solvent based sealer over water based sealer, or vice versa. It wont work out very well. Stick with one or the other.

Google Google Google sealing concrete. The internet is your friend.

Hope this bit of info helps,

 

[dd27]

Thanks for all the insights. I was going to replace the filters so decided to give them a power washing on a low setting. Wow, should have done that sooner. They're like brand new! Closed the pool today. Concrete contractor couldn't come back on Monday to seal because the air temps had dropped. I told them I was keeping the pool open any longer, too many leaves this time of year. They can seal it in the spring and that gives me more time to research.