Efflorescence Q&A: Getting To The Solutions

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Words: MASONRY Magazine
Photos: KaraGrubis

Efflorescence is a problem that can potentially ruin a brick building or wall. We sat down with industry suppliers to learn more information on what efflorescence can do to a wall or building and ways to treat the affected area and prevent it from happening again. Discover more ways to prevent and detect efflorescence from happening.

MASONRY Magazine: What are the early warning signs of efflorescence damage? 

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: While Efflorescence itself doesn’t typically cause too much damage, it actually tends to be one of the early warning signs of other, more significant issues. While new building bloom is commonplace in masonry, efflorescence itself is relatively harmless, albeit unsightly. Recurring efflorescence tends to be a sign of a larger water management issue. Efflorescence requires moisture to mobilize the salts and work its way out to the visible surface, so if you’ve got efflorescence, you’ve got a source of water ingress. In this case, efflorescence can be your best friend as it may alert you to leaks before the damage has a chance to progress any further.

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: The earliest sign of efflorescence is a constant or repeated water source infiltrating cementitious materials without the ability to breathe and dry out. In the beginning, it may simply look wet all or most of the time. During this time, it is constantly storing more and more salts. These salts will eventually migrate to the face and dry. If masonry is storing moisture or water, it will likely turn into efflorescence at some point in time. This is definitely the first sign.

M.M.: What are the best ways to treat efflorescence damage? 

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: The first step to addressing efflorescence, or any masonry stain for that matter, is stopping the source of water ingress, otherwise you’re addressing the symptoms, not the actual problem. Next is ensuring an accurate diagnosis. Splash a little water on it or rub your hand across the surface and see if that alters the appearance. If so, you’ve likely got efflorescence. If not, you may be dealing with one of the commonly mistaken stains like lime run. Like every masonry cleaning operation, removing efflorescence should be done by starting with the least aggressive means necessary.

Often times efflorescence can be removed with a mechanical process like brushing the surface with a masonry brush, or even just a low-pressure water rinse.  In the event, you need chemical assistance to fully dissolve and remove the salts, be sure to select a product that is proven to be safe on your substrate. Start with the mildest recommended dilution and progress to a more aggressive solution as needed. Always thoroughly pre-wet, apply the cleaning solution, and rinse the wall using low pressure so as not to drive the water, cleaning solution, or the contaminants deeper into the masonry pores causing the efflorescence to reoccur as it dries. Once dry, apply a breathable, penetrating protective treatment to help prevent the recurrence.

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: The very first step in treating should always be finding the problem or source of water intrusion and repairing it. Once the problem or source is fixed, efflorescence will often go away on its own. Commonly, new masonry will have some efflorescence because of the water used in the installation process and its contact with cementitious materials. This is called new masonry bloom. Understanding the difference in new masonry bloom and an actual reoccurring presence of water is important.

New bloom will most likely go away on its own, throughout the initial curing process or during the initial washdown. Fixing the source of the problem should always be the first step. If this is not done and the efflorescence is cleaned or removed, it will return in a very short time. When treating, harsh acids should never be used. Using specific and specialized cleaners is always the best practice as well as making sure the cleaner is intended for the material being cleaned to ensure no unwanted damage, etching, or color changes occur.

M.M.: What are some maintenance tips to maintain brick from efflorescence damage? 

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: Efflorescence needs three things to form: Soluble salts, something to solubilize them, and a migration path. Stop any of those three things and you stop the efflorescence. The salts and the migration path are inherent in masonry, so the one that you can eliminate is the “something to solubilize them.” In the case of common efflorescence, that tends to be water. By eliminating the source of the water getting into your wall, the salts will live peacefully out of sight.

The process off eliminating the source of water infiltration begins in the design phase by incorporating water shedding design details like overhangs and drip edges, and water management features like mortar collection devices, weep holes and proper joint profiles. Once the building is complete be sure to wash it with a proprietary masonry cleaner designed for that specific substrate to minimize the chances of additional salts being mobilized, then apply a breathable penetrating protective treatment to keep the wall from absorbing water.

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: Masonry is extremely resilient and is designed to be able to withstand getting wet and drying out without issues. Maintenance issues often occur with other materials that are in contact or relationship with masonry. These areas often include sealant and caulk joints, roof flashing, wall caps, parapet caps, and leaky downspouts. Another issue comes from sprinklers that are improperly aimed or adjusted and are soaking the masonry daily. These are the areas that will continually allow water to intrude in areas other than the face of the surface.

Ultimately, keeping the masonry free of voids and open cracks to maintain its continuous surface is the best method of maintenance. This includes sills with full, struck head joints, preferably with through-wall flashings installed underneath them. In cavity walls, keeping the weeps free and clear of debris is also critical to promote proper cavity ventilation.

M.M.: What are some common misconceptions about efflorescence? 

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: The biggest misconceptions about efflorescence tend to be born from a misdiagnosis of the conditions. Efflorescence in its most common form is relatively easy to remove. It’s those stains that appear to be efflorescence at a glance, like white scum, sealer blush, lime run or hard water stains, that are much more difficult to remove. Not everything white on the wall is efflorescence. A quick water splash can tell you if that’s what you’re dealing with or not and save you time and money in identifying a solution. 

Another common misconception about efflorescence is that it is always that white powdery stain on masonry walls. By definition, “efflorescence” includes a wide variety of salts that are mobilized and brought to the surface of a porous material, not just the common sodium chloride salts. Many manufactured masonry products contain other forms of salts like vanadyl sulfate or manganese oxides used as colorants that can be broken down by improper cleaning materials and/or methods and can be much tougher to remove. Using the appropriate cleaner for your specific substrate is your best bet at preventing these other types.  

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: Brickwork with efflorescence bloom can be deceiving. Often, the efflorescence is covering the face of the brick units as well as the mortar joints. The source is often water reacting with the mortar and not the brick, but migrating across the surface of the brick. Efflorescence is often mistaken for other stains that are simply that, not a blooming reaction. Hard water, rust, and other minerals are deposited to the surface, staining it. These are stains, not blooms.

Lime run is often thought to be efflorescence. Preventing and cleaning lime run should be addressed differently than efflorescence bloom. Being able to differentiate these will aid in working your way through the misconceptions and treating each problem accordingly.

M.M.: Can you protect from efflorescence during the construction process and if so how?

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: During construction, there are a few easy steps you can take to help minimize efflorescence bloom. Start by making sure that when materials are delivered to the jobsite that they are stored off the ground and protected from the elements. As the wall goes up, be sure to temporarily cap the wall at the end of each day and/or prior to weather events to keep unnecessary water out. As you build the wall, help it manage the water that will inevitably get in with things like mortar collection devices to keep the weep holes free draining, proper ventilation convective drying, completely filled, and properly tooled mortar joints and adequate flashings and sealants. When the wall is complete, wash it with a product designed specifically for the substrate you’re working with and apply a breathable penetrating protective treatment that keeps bulk water out, and allows water vapor a path to evaporate. For both cleaners and protective treatments, one size does NOT fit all masonry types and raw muriatic acid is NEVER the right choice. 

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: There are many ways to prevent this problem during construction. Keeping your materials off of the ground and covered is simple and effective. Keeping walls covered when not working on them is also beneficial.  Always use clean, potable water when mixing mortar, cement, grout, etc. This will help eliminate other alkali or impurities. Keeping cavities as clear as possible to eliminate mortar bridging should always be a priority. It comes down to using best practices throughout the build, right down to properly installed weeps, and adequately full head and bed joints. The fuller they are, the less room there is to store water. Regarding weeps, they are only as good as the mortar collection devices being used. Keeping the sluffed mortar from blocking the backside of the weep is a must.

M.M.: What are some common mistakes made when treated efflorescence damage?

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group:

  1. One common mistake is using a cleaner and/or concentration that is far more aggressive than necessary, which can lead to other, more significant damage. Every industry organization agrees that your best bet is to start with the least aggressive means necessary. Don’t break out the sledgehammer for the finish nails.
  2. NEVER use muriatic acid as it is unbuffered and impure. There are countless purpose-built products available at competitive costs. 
  3. Never apply an acidic cleaner to a dry wall, or leave it on the wall without a thorough rinse. Any time you apply a cleaning solution to the wall, you should thoroughly rinse to remove the cleaner residue, and the contaminants it has broken down, otherwise you allow those contaminants to redeposit on the wall in other areas. 
  4. Especially with a stain that is water soluble like common efflorescence, you should always clean from the bottom up, keeping areas below the work zone saturated to prevent the partially dissolved contaminants from running down and absorbing into a dry wall. 

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: Using high pressure when washing is the first thing that comes to mind. Driving moisture deep into the surface will only add to the bloom. Water is the source that feeds efflorescence, so use as little volume and pressure as possible when trying to remove it. There are effective cleaners on the market that do not require the use of water for this specific reason. The use of strong cleaners and harsh acids should not be used, but often are. Though they might clean it off of the surface, they can damage materials, which will actually promote more efflorescence. They also require a lot of water to properly rinse, which will support more bloom.

M.M.: What are some little known facts about efflorescence?

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: Efflorescence comes in many different forms. The majority of the industry only refers to “efflorescence” when talking about the white powdery deposits on the surface of the wall, when in reality it comes in a variety of colors and severities. Green vanadium, brown manganese, white calcium carbonate and more would all technically fall under the umbrella of “efflorescence” but aren’t commonly referred to as such. 

Efflorescence can come from a number of sources, including the ground itself. Be sure to take preventative measures whenever possible to reduce the chances of it showing up on your job. 

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: When diagnosing efflorescence, it will look clear while it is wet, or nearly clear (just mild haziness). If it is still boldly white the problem area is wet, you are looking at a different problem. This could be hard water, hard calcium, lime run, or even white paint. Efflorescence is basically salt build-up. If you put salt in a glass of water it goes from white to a hazy, almost clear substance. This is no different. It will often wipe off on to your finger as a powdery substance and taste like salt. I don’t suggest tasting it, but I am guilty of using this method to determine if I was looking at an efflorescence problem.

M.M.: Do you have anything else you would like to add?

Jake Boyer, Business Unit Leader of PROSOCO’s Clean and Protect Group: Never go it alone. There are a number of industry professionals whose lives are dedicated to helping you identify, remove, and prevent stains like efflorescence and others. Don’t hesitate to ask for help and keep your time free to do what you do best. 

Never apply a film-forming protective treatment in areas subject to water as they prevent the substrate from drying out. You’ll eliminate one of the three requirements for efflorescence by blocking the migration path, but that efflorescence will still form, just below the visible surface. This condition is called sub-florescence where the salts crystalize inside the masonry pores and expand leading to spalling and substate degradation. Much more costly than a little white powder on the wall. Using a protective treatment that keeps bulk water out but allows the substrate to maintain its natural breathability is key. 

Jayson Kellos, Architectural Representative – Western Region, Hohmann & Barnard by MiTek: Educating yourself on how to recognize efflorescence is important. Using best practices and procedures throughout the build will aid in prevention. Using quality materials is just as important. Open communication with designers and other trades about possible problem areas should be a goal. Let’s face it, the design can also be the problem, no matter how it is installed, treated, or maintained.

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