BajaNomad

Need Cement Experts

Pescador - 2-3-2008 at 09:01 AM

Ok, we just had some new cement work and some saltillo tiles put in on the back porch area. We have started growing snow as this dries. I tried using citric acid to nuetralize but it still keeps coming back. Someone said to try using Muratic acid but I don't know what kind of concentration to use.
So, is Muratic acid the right thing to use, and what kind of concentration would be best.

DENNIS - 2-3-2008 at 09:13 AM

Full strength muriatic acid will etch the surface. I've seen toilets after full strength was used to take out lime deposits and the porcelan is ruined. Of all places imaginable where you would want a smooth surface is in your toilet.

Were your tiles sealed?

I researched this white, foamy crap that comes to the surface of concrete. I'll let you do the same as I probably forgot more than I can recall.
Take it to Google. There's a lot of info on the subject.

DENNIS - 2-3-2008 at 09:40 AM

Quote:
Originally posted by morgaine7
Funniest thing ... same here!! :(
We ran out of sealant during the installation, and the unsealed tiles are white around the edges.


Jeezo, I hate to hear these things. The tile should have been sealed before it was placed on the floor. Saltillo is so absorbant. Your maestro might use a silicon grout sealer. There seems to be a fix for everything in Mexico.

Ken Bondy - 2-3-2008 at 09:45 AM

Efflorescence occurs whenever liquid water comes in contact with any cementitious surface. Soluble salts in the cementitious material are dissolved by the water, and are left on the surface of the concrete/grout/masonry etc. as a white, chalky stuff when the water evaporates. It is purely cosmetic, it will have no effect on the strength or functionality of the material. The Portland Cement Association (Design and Control of Concrete Mixtures, 14th Edition, p.212) recommends simple cleaning with water. The efflorescence will eventually stop. For a chemical cleaner PCA recommends a 20 to 30% solution of diammonium citrate, which I THINK is called citric acid.

++Ken++

BajaWarrior - 2-3-2008 at 10:15 AM

I built a brick home in La Bocana de Santo Tomas about 13 years ago. The first winter the "white stuff" appeared on the walls even the interior brick walls which I thought maybe was salt as well water near the coast was used. Of course, the camp owner/contractor Sergio Gomez just shrugged his shoulders as it didn't seem to bother him...!

I moved the furniture away from the walls and went nuts with a push broom on the walls, then cleaned it all up with the vacuum, it did not come back the next year. I assumed it "died".

Don Alley - 2-3-2008 at 10:56 AM

We've gotten that on unsealed saltillo tile, and colored concrete stepping stones. When we sealed the saltillo it came up under the seal and the seal peeled up.

We thought it was a Big Problem.

Then it went away. No problem now.

If I could do it over again I'd just mop and sweep, and wait until it stops "snowing" to apply the sealant.

Pescador - 2-4-2008 at 02:58 PM

I had a batch of citric acid and it really made a difference but I do not have any more. I know that muratic acid will etch if it is too strong but in a weaker solution it should be able to nuetralize the alkalinity which is what I think causes this stuff. The surrounding tile is fine but where we added the new section is where we have the most. I agree that you don't want to seal this stuff until it is done "efflorescing". Thanks for all the help.

Gadget - 2-4-2008 at 03:54 PM

Quote:
Originally posted by DENNIS
Quote:
Originally posted by morgaine7
Funniest thing ... same here!! :(
We ran out of sealant during the installation, and the unsealed tiles are white around the edges.


Jeezo, I hate to hear these things. The tile should have been sealed before it was placed on the floor. Saltillo is so absorbant. Your maestro might use a silicon grout sealer. There seems to be a fix for everything in Mexico.


That's it right there. Saltillo must be imersed in sealer prior to install. The high lime content in the grout will continue to efflourese into the unsealed edges of the saltillo even if the grout is sealed. The density of saltillo is so random that even when pre-sealing it you can get some that will and some not. Then you call it "patina" and forget about it. :biggrin:

robrt8 - 2-4-2008 at 04:09 PM

It sounds like the saltillo was laid before the concrete cured. Happens all the time. Don't use acid yet. Wait a few weeks for the salts to finish migrating to the surface & try out a small area with soap and a scotchbrite pad. Then you can start with acid if that doesn't work, but it should. First try sulfamic acid, then try muriatic only as a last resort and very diluted.
Muriatic will work but etch the tile rapidly.
After left to dry for two days, seal it. Let me know if you have any more questions.

Marie-Rose - 2-4-2008 at 09:12 PM

We have a little patch of the same around a couple of our tiles and then lots on a cement
wall that will one day be covered with tiles as well. When I showed our contractor, he recommended painting the cement and all the outside tiles with a light coat of diesel fuel:?::?::?: They also treated all of the wooden beams and palo de arco with diesel fuel to protect against insect infestations and recommended doing so every year.