Calcium Deposits on Brick - Contractor Talk - Professional Construction and Remodeling Forum

brainswell · 09-06-2007, 09:13 AM

Would like to know if any of you PWashers have ever encountered Efflorescence on brick? I can best describe it as something that looks like calcium/salt deposits that have leached out of brick or the mortar? If you have ever encoutered this, did you have success removing it? If yes, please let me know your method.

We have encountered this on a few schools in the Orlando area and have not had success to my satisfaction removing this stuff. We've tried the following:

CLR - did not work
Diluted Muriatic Acid - maybe 25% effective
100% Muriatic Acid - 50% effectiveness at best, really nasty to work with.

In conjuction with the above we used stiff wire brushes with the acid solution and then hit the areas with either a 4000 or 4500 psi machines with a turbo nozzles. Even with this, I cannot completely remoze this stuff.

I will try and post some pictures I took with my phone.

Thanks,
Brian

Celtic · 09-06-2007, 03:55 PM

I have some of that on my porch that was rebuilt last year.

Here is some brief info (more at http://en.wikipedia.org/wiki/Efflorescence )

Quote:

Primary Efflorescence

Primary efflorescence is named such, as it typically occurs during the initial cure of a cementitious product. It routinely occurs in masonry construction, particularly brick, as well as some firestop mortars, when water moving through a wall or other structure, or water being driven out as a result of the heat of hydration as cement stone is being formed, brings salts to the surface that are not commonly bound as part of the cement stone. As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit, that can normally be brushed off. The resulting white deposits are referred to as "efflorescence" in this instance. In this context efflorescence is sometimes referred to as "saltpetering." Since primary efflorescence brings out salts that are not ordinarily part of the cement stone, it is not a structural, but, rather, an aesthetic concern.

Secondary Efflorescence

Secondary efflorescence is named such as it does not occurr as a result of the forming of the cement stone or its accompanying hydration products. Rather, it is usually due to the external influence of concrete poisons, such as chlorides. A very common example of where secondary efflorescence occurs is steel reinforced concrete bridges as well as parking garages. Saline solutions are formed due to the presence of road salt in the winter. This saline solution is absorbed into the concrete, where it can begin to dissolve cement stone, which is of primary structural importance. Virtual stalactites can be formed in some cases as a result of dissolved cement stone, hanging off cracks in concrete structures. Where this process has taken hold, the structural integrity of a concrete element is at risk. This is a common traffic infrastructure and building maintenance concern. Secondary efflorescence is akin to osteoporosis of the concrete.

Protecting Against Efflorescence

It is possible to protect porous building materials such as brick, tiles, concrete and paving against efflorescence by treating the material with an impregnating, hydro-phobic sealer. This is a sealer which repels water and will penetrate deeply enough into the material to keep water and dissolved salts well away from the surface. However, in climates where freezing is a concern, such a sealer may lead to damage from freeze/thaw cycles.
Efflorescence can often be removed with diluted phosphoric acid (usually about 1 part acid to 10 parts water, but follow the directions on the bottle). Always test some of the acid solution on an inconspicuous area first to ensure it will not discolour the surface material. The acid dilution should then be neutralised with mild diluted detergent, and then be well rinsed with water.
The source of the water penetration should be addressed. If the water source is groundwater or faulty flashing the efflorescence may reappear, unless properly sealed.
Common rebar protective measures include the use of epoxy coating as well as the use of a slight electrical charge, both of which prevent rusting. One may also use stainless steel rebar.
Certain cement types are more resistant to chlorides than others. The choice of cement, therefore, can have a large effect upon the concrete's reaction to chlorides.

carolinaprowash · 09-06-2007, 05:33 PM

We've found all the help/product we'd ever need at www.eacochem.com. The products are top notch, the knowledge and customer service are second to none!

Celeste

lukachuki · 09-06-2007, 05:44 PM

search over in the masonry part of this forum. There has been some good advice given over the years.

I was in my local tile and stone shop yesterday and they had a specially formulated efflorescence remover that they said worked quite well. It was not muratic. This is their website you could call and get the manufacturer.

www.tilecenter.com I was in the Augusta store.

tom connelly · 01-17-2008, 04:47 PM

Hate to say it, but you probably just made everything worse. especially using muriatic straight. yeah its nasty. but not just for you. it will burn your brick, eat the cream out of the mortar joints (which can cause them to crack and pop out with time), and if used incorrectly, (which straight is incorrectly) you can make the stain even worse by creating white scum, or what they call clean up efflorescence, or acid burn, along with a lot of other problems.
eaco chem
is definately a great choice, and they can get you on the right track. they are our favorite chemical company, and they can answer all your questions.
hope you get it resolved.