efflorescence on mosaic on concrete planters

[cindy fisher]

I've been reading about efflorescence on the site as well as forums, and didn't find exactly what I am looking for so will post here. I did an installation of glass mosaics on 7 concrete planters outside a school here in Massachusetts. They are 2' high and 7' in circumference. THey are filled with soil, and I am thinking this is the reason for the efflorescence. My specific question, is it the capillary action of the soil draining through to the surface of the mosaics, and if the soil were removed from the planters, the problem will not return?!? I am sure HOPING this is the case, but wanted to seek the advice of you experts before recommending this to the art teacher at the school. PS photo is on its side, the drips are actually going down, not across Many thanks, Cindy

[Ron]

Hi Cindy,

Efflorescence occurs when moisture is trapped too long under a tile. If it was a more breathable finish this probably wouldn't happen. Yes, the wet soil is contributing to it. You can remove the stains with a mild acid cleaner and a white Scotchbrite pad... rinse well and dry it off.

To prevent it, you'll have to line the inside of it with something. You could also paint it with a liquid waterproofing membrane.

Nice planters!

[cindy fisher]

thanks a lot, Ron. I will forward this to the art teacher, I really appreciate your taking the time to respond, Cindy

[jmuellejans]

What should I use to remove efflorescence deposits which dried onto the vertical GLASS surface of our mosaic planters?

In early June, 2015, we installed glass mosaics on 7 concrete planters outside of the school where I teach art. After the first heavy rain, the soil got saturated, and the inside of the concrete planters soaked up the water to capacity. The excess water then worked its way through the grout lines, on the outside of the mosaic. Water dripped down the vitreous and stained glass tile, dried and left hardened mineral salt deposit drips everywhere.

I was able to scrub off an area by hand, using a little water on green Scotch Brite and a lot of elbow grease! I cannot imagine doing this on 126 square feet and am looking for a product which will:
make removal easier
not damage the glass - scratch, frost, pit the surface, etc.
not damage or dissolve the grey Mapei sanded grout we used.

Mapei suggests I use their Ultracare Efflorescence Remover, which contains sulfamic acid. The data sheet does not mention glass as an recommended surface for this product. Plus the instructions for using this product sound risky, especially if it dries on the glass, etc.

Another product I am considering is Aquamix Nanoscrub, which is a limestone clay suspension, a liquid abrasive particulate which they claim will make it easier to remove efflorescence with scrubbing, won't discolor or damage the glass or grout and rinses off easily. Does it work? The rep at Aquamix said baking soda in water might be all I need to use if the mineral salt build up is light, which it is, although it's quite hardened, having sat in the summer sun since late June. Sodium carbonate is in fact one ingredient in Nanoscrub.

Thank you in advance for your time and consideration.

We are about to remove soil, raise up the planters on paving stones and install plastic inserts which will contain the soil and create a ventilated, well draining interior.

I plan to remove efflorescence from the inside concrete walls using a sulfamic acid like UGL's Etch. I then plan to apply UGL Drylok Extreme Masonry Waterproofer to seal the inside of the planters and along the non-grouted top rim, which should waterproof yet allow moisture trapped in the concrete to evaporate through the surface. Hopefully all these measures will prevent further efflorescence and protect the mosaics from the forces of winter's freeze-thaw cycles. We plan to cover the tops of the mosaics during the cold New England months. Attached are some photos.

[Ron]

Hi Julie,

That's very nice mosaic work!

I replied to Cindy who posted a question and photo relating to the same project a while ago. This remedy will work and won't damage the glass tiles or grout. Sulfamic acid crystals are best for making a mild acid cleaner. Start with a weak mixture and scrub it with a white Scotchbrite pad. Rinsing well and drying is very important so that you don't leave a residue of the acid solution. I assure you it will work!

"Hi Cindy,

Efflorescence occurs when moisture is trapped too long under a tile. If it was a more breathable finish this probably wouldn't happen. Yes, the wet soil is contributing to it. You can remove the stains with a mild acid cleaner and a white Scotchbrite pad... rinse well and dry it off.

To prevent it, you'll have to line the inside of it with something. You could also paint it with a liquid waterproofing membrane.

Nice planters!"

[Houston Remodeler]

Lining the inside is a great idea. It will need to be durable enough to take the rigors of root growth (which can split rock) A removable liner may be your best bet. That liner should have holes in the bottom to allow for drainage.

What I think you are seeing after all these years is the salts from the plant food coming through. Since you can't stop feeding the plants, a liner would do the trick.

[cx]

Welcome, ladies.

One thread on the project should be enough, eh?

[jmuellejans]

Sorry CX...Cindy encouraged me to add more details. I guess I should have replied under her initial post...Hope this doesn't add confusion to the discussion. I am a newbie in here, learning the ropes.

[jmuellejans]

Paul,
Great suggestions, thanks.
We plan to remove the annual flowers each fall before first frost and cover the tops to keep the soil dry and snow/ice, etc, out.

[jmuellejans]

These photos show the inside of one of the now empty planters. My hand gives some scale. Note I have small hands.

There are a ton of small hole and you can see a narrow crack in the second photo.

I am wondering if it's enough to really work the UGL Extreme Masonry Waterproofer into the holes with a brush?

What size holes and cracks need to be filled before sealing the inside with UGL Extreme Masonry Waterproofer?

[cx]

Give us a link to the waterproofing material you have in mind, Julie, so we can all be onna same page.

I don't see anything in the photo that would not cover adequately with any of the concrete waterproofing materials with which I'm familiar, though.

My opinion; worth price charged.

[jmuellejans]

UGL Drylok Extreme Masonry Waterproofer
Website: http://www.drylok.com/formulas/drylok-extreme/
Data and Spec sheets can be downloaded.

[cx]

I can't tell for sure from their data sheet how viscous the material might be, Julie, but the general impression I get would lead me to paint a coat over any cracks or heavily pitted areas before applying the required two coats of material. See my warranty information below.

My opinion; worth price charged.

[Houston Remodeler]

I'd also check with the manufacturer on how well plant material gets along with the cured /dried product

[jmuellejans]

Thanks Paul and CX.

I am preparing to waterproof the inside of the planters. Today I etched the inside concrete surface with UGL Drylok Etch - a sulfamic acid,
http://www.drylok.com/formulas/etch/ mixed 12 ounces of sulfamic crystals to 1 gallon water. I hope this removed any efflorescence on the inside.

I decided to test the UGL sulfamic acid solution on a small section of glass tile to see if it would remove the efflorescence. It instantly dissolved the efflorescence which had dripped, dried and hardened on the glass. I rinsed and dried the stained glass tile and it looks great.

I called UGL to inquire about this use. They tell me NOT to use their product on the glass mosaic, as it will likely damage the glass - etch it, cause it to get a white frosted look. I used so many types of glass in this mosaic I cannot test for each of them.

On the other hand, Mapei tells me sulfamic acid on glass is safe if it's not more than 10 to 12% in a water solution, although Mapei's sulfamic product does not list glass as an acceptable material. http://www.mapei.com/us-en/product-d...32&IDLinea=143 UGL was not able to tell me the percent of sulfamic acid in their product when mixed 12 ounces to 1 gallon of water.

I have gotten what appears to be conflicting information from manufacturers, tilers and retailers. I suppose it depends on the product and the fact that my cirsumstances seem to be very unusual.

Has anyone had experience and recommendations about safely removing efflorescence from glass mosaics and their accompanying grout? Note that I plan to seal the grout after with a penetrating, breathable water repellent.

Thanks in advance.

Pix - thankful for friends who helped shovel tons of gravel and dirt
- planters now raised on pavers