Anything you can do to minimize water migration under your concrete will help. This can easily be removed by sweeping the concrete with a wire brush. The surface may be opened immediately for use. Once the moisture levels are established a sealer can chosen based upon the manufacturer's recommendations. Unlike traditional sodium silicates, this sealer unlikely leave residues such as white effloresce or other unwanted residue discolorations on the treated surface. It means doing a VTR test whenever you suspect there may be the potential for efflorescence problems. Blistering is rarely seen with acrylics. White stains or a white powdery coating on new concrete is not uncommon. If excess SP-450 is allowed to dry on the concrete surface, a white residue may form and can only be removed by mechanical means such as sanding or grinding process. Copyright 1999-2020 ConcreteNetwork.com - None of this site may be reproduced without written permission. The bad news is that this can take as long as 15 years. Efflorescence that becomes trapped under sealer is unsightly and is even more conspicuous on darker floors. No matter that the heat is not yet on in the building and the floor is not fully cured out. When a densifier is applied to the surface of concrete the silicate begins to immediately react with the calcium hydroxide. High slump concrete and the addition of calcium chloride are major contributors to efflorescence. In fact, I have seen decorative concrete and concrete overlays that have severe efflorescence but are light in color, so the efflorescence is barely noticeable. Decorative floor contractors would be well served to explore this technology even for smaller residential stained floors. If a vapor retarder was used, was it carefully taped at penetrations, around the plumbing, for instance? It may seem simple but concocting the exact ratio of these three components is tougher than you think. Fly ash reduces the amount of Portland cement and free lime as well as chemically binding up a portion of the free lime and salts that cause efflorescence. Concrete is composed of three ingredients, Portland cement, aggregate and water. Heads up on this one... cold concrete and cold ambient temperatures encourage efflorescence because the salts are actually more soluble in colder temperatures plus concrete tends to bleed more in cooler weather further encouraging the upward transportation of moisture and its passenger, soluble salts. If the water movement is high, a more drastic and aggressive topical waterproof coating may have to be used. More accurate, but also more expensive, testing technology such as the Protimeter Moisture Measurement System (ASTM Standard F-2170-02) uses a probe to measure the presence of moisture on and below the concrete surface along with the relative humidity, dew point and temperature. Some of these are used in the conjunction with polished concrete floors. Another important mix design consideration is the replacement of 15% to 20% of the Portland cement with fly ash which contributes significantly to lessening efflorescence. If urethanes or epoxies are on the floor, hydrostatic pressure may build and possibly cause delamination. Existing Concrete: Apply at a rate of 200-300 sq. According to the Internet, “A concrete densifier is a chemical applied to a concrete surface in order to fill pores, increasing surface density. Fly ash brings three important benefits to reducing efflorescence. Product Description. Concrete densifier and hardener, compatible . All rights reserved. There is one more complication all too familiar to staining contractors...the schedule. We like the concentrated Lithi-Tek 4500. Why is the sample exposed to the air loaded with efflorescence while the other sample has no effloresce and is the proper color? What do you suppose the chances are that the stained and sealed floor will escape with no efflorescence? Normally when calcium hydroxide comes to the surface of fresh concrete, it reacts with atmospheric carbon dioxide, producing carbonation (calcium carbonate). Add that amount of water to another 60 or 70 extra gallons of "water of convenience" added by the finisher and we may have 270 gallons of extra water moving towards the surface whenever surface conditions are warmer or drier than the slab itself. The test results will dictate your next step. That being said when you buy a home that already has a poured concrete basement, driveway, patio etc. It is important to get it right the second time so take time to diagnosis the causes as best you can with the information available. The picture shows two small samples of the overlay taken from material left in the mixing bucket. When a concrete cure is used, it optimizes conditions for the concrete to allow for the development and maintenance of volume stability, strength, and resistance to abrasions, freezing, and thawing. The process involves natural salts migrating out of the concrete (or mortar, block, or brick), in a. chain reaction triggered by water and carbon dioxide. Do Not Thin! Chris Sullivan is a decorative concrete expert who answers technical questions from contractors and homeowners concerning efflorescence and other issues. Contact a concrete contractor near you. Deposits of efflorescence make black concrete look grayish-white. We have thought about tiling over it, but are any special preparations necessary, such as applying a thin-set mortar or a moisture barrier? Some contractors are following the application of acid stains with silicate type non-film forming sealers generically described as chemical hardeners, densifiers and soluble chloride reducers within a few days of concrete placement. Efflorescence will not only cause problems with a stained concrete floor, it can also delaminate tile and warp wood floors. ♦ USES • Densify and color concrete preliminary to . Efflorescence is normally worn off or washed away on unsealed concrete surfaces. If you then want to restain the floor, a cement and polymer topping would need to applied to create a new canvas on which to apply the stain. Not only does densifying begin but the once empty pores of the concrete are filled creating a tougher, stronger concrete slab. ft. per gallon using an industrial grade sprayer with a 0.5 gal./min. It can pose real problems for the stain contractor since a common ingredient, stearic acid, is hydrophobic in the same way that powdered release agents for stamped concrete are so the waterproofed concrete does not readily accept either acid stains or water base stains. Testing the surface may not be enough to guarantee an efflorescence free project for years to come. The stains are normally white and are present in darker colors more than white or pale colors due to the contrast created by the chemical reaction. This is added to the concrete at the plant, but it has a downside. Due to the high activity of lithium silicates, TECH-DRY DENSIFIER accelerates the concrete polishing process, thus saving time and costs. Efflorescence is caused by vapor migrating through the slab bringing soluble salts to the surface of the concrete. Unfortunately, too many finishers (non-ACI Certified Finishers) routinely introduce large amounts of unnecessary "water of convenience" to the mix in order to facilitate concrete placement. Follow through with additional polishing steps until desired appearance is achieved. Why cant I use this product on brick or concrete blocks? All these factors contribute to a concrete that has a minimum amount of bleed water with a lesser pore and capillary network that will resist rather than facilitate absorption and movement of moisture...in other words, a dense and relatively impermeable concrete slab. The benefit of these tools is their accuracy in measuring the moisture levels well beneath the surface whether there is any current movement or not. How do you prevent and remove it? It is an aesthetic issue, an issue we would all like to avoid. When can I polish a floor after using LS? Since you have had this issue since you've lived in the home, it seems to be chronic and ongoing. This sample also has a smoother, denser surface that inhibits water migration. Yet only the one on the left shows efflorescence. Since colloidal silicas have the ability to bond to itself (silicate sealers cannot do this) it can densify stronger and has the ability to bond to cement products not made from regular Portland cement. ft. per gallon using an industrial grade sprayer with a 0.5 gal./min, fan tip, lint free mop, or soft bristle push broom. Question: A few days after placing a stamped overlay, I noticed that the overlay was covered with efflorescence. That can be at the 200- or 400-grit resin level. Without moisture movement there would be no efflorescence on the surface to create the problem. The most advanced concrete densifier available. What are the options when efflorescence rears its ugly head? Consider vapor testing and resist the quick fix. This creates a harder surface and decreases staining. Some are used on floors already acid stained or dye stained and could receive a membrane type sealer. Contact us and view our privacy policy, terms & conditions, and press room, Causes of Efflorescence on a Stamped Overlay. Efflorescence is a process where salts leach out of the concrete, carried by water, and end up on the surface as a white dusty residue. The fact that these salts are actually more soluble in colder temperatures coupled with increased bleed water in cold weather increases the likelihood of efflorescence showing up after winter concrete placement. And never add water to the surface. If the proportions are even slightly off it will result in weakened concrete that will begin to deteriorate. Remember that some manufacturers have the vapor inhibiting, non-film forming sealers that we mentioned earlier. © 2020. Best Concrete Water Oil and Stain Repellent Sealer with Saltguard. Stain contractors, concrete finishers, builders, general contractors, the design community and owners are all affected by issues related to efflorescence. Two non invasive hand held devices using similar technology are the Aquant, which measures surface moisture to a depth of 10 – 20 mm and the Tramex Concrete Encounter Moisture Meter which transmits a signal ½" deep and projects a moisture measurement for 4". Efflorescence is not a structural issue. In worst case scenarios where the vapor cannot pass through the top coat, a urethane and/or an epoxy for instance, hydrostatic pressure can build to create water blisters indicating delamination of the top coat from the concrete. Chemical densifiers are used on polished and non polished slabs to reduce dusting and wear; on polished concrete surface densifiers help concrete take a better polish and make the surface less permeable to liquids so the slab does not require sealing.”. Both concrete densifiers and cures are excellent for improving concrete strength and general durability. Wet curing is difficult because it must be continuous and may create discoloration if a plastic sheet has wrinkles. We will offer useful explanations of this complex phenomenon in practical terms without a lengthy detailed chemical analysis. There are a few types of concrete densifiers on the market today. Question: We have a stained concrete floor slab on grade in our Houston home. If applied too heavily, an unreacted white residue may develop on the surface. Doug Bannister is owner of The Stamp Store in Oklahoma City, OK, which provides a complete line of decorative concrete materials including products, equipment and training. If you have a lot of residue on the surface, you will want to use an autoscrubber with a white pad and water to clean the surface, allow the surface to dry, and then apply your densifier/dye mixture. Imagine the consequences of the following unpleasant, but very real scenario... the project is completed, the contractor has been paid, the delighted owner takes possession and turns on the HVAC causing vapor in the slab to move towards the warmth or the lower humidity of the conditioned space bringing the whitish minerals with it. It can work alone or as a primer for other products in the Ghostshield family. SurfKoat Aqualon S-400 is an economical sodium silicate concrete densifier, hardener and sealer used in the process of polishing concrete. This white, dusty, scaly salt can be minimal or dramatic, depending on the amount of free calcium salt present in the concrete. Another surface moisture test is The Calcium Chloride Test which quantifies the rate of vapor transmission. Some of these chemicals have been used for years and some are relatively new to market. When concrete is kept moist for a longer period, especially the first few days, more capillaries and pores fill partially or completely to form a denser and more impermeable matrix that discourages the migration of moisture and soluble salts. The decorative contractor, being the sincere person he or she is, has proposed an upgrade from the acrylic sealer in the specifications to an epoxy or urethane because of the heavy foot traffic. What is a concrete densifier, and what is the best concrete densifier? This article is meant to be a common sense overview of the major efflorescence issues. The amount of these salts, and the resulting difficulty of removing these white stains, depends on many factors, including the amount of salt dissolved in the water used to mix the concrete, the concrete itself and the amount of salt present in the sand and gravel used in the preparation of the conc… It looked great for three days, but then it rained a little the night of the third day, and by the next morning all the black color had disappeared, hidden by a grayish-white surface discoloration. Such discoloration, known as efflorescence, is caused by salts that are brought to the surface of new concrete by the natural curing process. Concrete densifiers are silicate sealers of a sodium, potassium or lithium carrier designed to densify, harden, dustproof and increase the abrasion resistance of concrete. Given the financial risk, not to mention damage to a contractor's reputation it makes sense for a contractor to explore procedures that more clearly indicate subsurface conditions in order to avoid the efflorescence problems caused by moisture. The recommended temperature and humid-ity ranges for densifier application vary from Efflorescence is a fact of life with most concrete. Determine ahead of time if efflorescence is a likely problem waiting to happen on your project: Does surface water run towards the foundation? That's why we created concretesealerreviews.com, we've tested, tried and reviewed each and every concrete sealer on the market giving you our take. When extra mix water and extra soluble salts from calcium chloride are added to concrete placed in cool weather followed by more water from the decorative processes, some degree of efflorescing is bound to occur. The argument against the granular material is that it may become a saturated "blotter" before the slab is poured adding even more water that has only one way to leave. A newer technology on the market is a colloidal silica densifier. This is a covered dish that is weighed before and after a twenty four hour period. The sample on the left side of the picture has a rough, open surface and is very porous, which allows for easy water migration. Now for more specifics...an option to the vapor retarder is a waterproofing admixture to help prevent efflorescence. Our contractor friend, by the way, does not have floor scrubbers. Instead, most websites only offer information that directly supports their product, which may or may not be the best actual advice. A mix with too much water will also experience increased shrinkage and visible cracks which will also affect the strength of concrete. Allow the product to dry and then check the surface of the concrete for surface residue. GhostShield 8505 is a penetrative, non-film-forming garage floor sealer designed to resist water, salts and automotive fluids. Scrub well with a floor machine and a soft bristled brush to remove the residue and rinse well with water. How old is the slab, what time of year was it poured? Claims vary from product to product and from manufacturer about how far the chemicals penetrate, their permanence and the levels of shine and slip resistance. This seems workable, life is good. Concrete densifiers are chemicals that are applied to the surface to: 1)Fill in the pores at the surface 2)Increase surface density 3)Improve the wear resistance 4)Reduce dusting Concrete densifiersare typically water based and include sodium, potassium or lithium silicates. When it comes to the water-cement ratio, less water is always better. Where slabs have continued to have efflorescence problems even after the application of a lithium or silicate densifier contractors have used a finish or polish, which are industrial grade "mop and glow" - low build, low solids micronized acrylic water based products as the final treatment. Most commonly used on warehouse floors in conjunction with a floor machine to polish and add a shine. Water is used to help re-move any remaining densifier. To learn more about efflorescence, read my post on the topic: Causes of Efflorescence on a Stamped Overlay and Efflorescence Hides Integral Color. Once the floor is dry, you can start polishing. Mops and buckets make up the clean up and water removal equipment. Some densifiers can be applied at time of placement where others see problems and need to wait for at least the 3 days to cure. Once the concrete reaches its point of absorption any material that was unable to penetrate reacts with the carbon dioxide in the air. If water is not fully absorbed through hydration some of it may evaporate as it hardens resulting in bleeding that will reduce the final strength of concrete. This reaction leaves a white, powdery residue on the surface of the concrete. Primary efflorescence is caused by the water in the concrete evaporating from the slab leaving behind the soluble salts on the concrete surface. These two samples come from the same bucket of overlay mix. A Calcium Chloride Test is a good surface moisture test for determining the current vapor transmission rate of concrete. Allow the floor to … The average dry time is 1 hour. If excess Armor S2000 is allowed to dry on the concrete surface, a white residue may form and can only be removed by mechanical means such as sanding or grinding process. Exposure to rain, standing water, and sprinklers only make the situation worse, as water triggers the reaction and creates more efflorescence.Efflorescence is not as noticeable when it occurs on gray concrete, but even a little efflorescence on colored concrete can be a contractor's worst nightmare. Moisture migrates and moves toward cool temperatures. It is claimed that colloidal silicas are the silicates of the future since they have a low viscosity, penetrate deep and also react with lime found in concrete. Efflorescence is reduced as the silicate causes the matrix to become denser as we described earlier. Shop Now. Follow ACI 306 Cold-Weather Concreting procedures whenever possible including raising the placement temperature of the concrete to 60 degrees and then cover overnight to retain the heat. Concrete Sealer Reviews. We know for certain that the big box stores are getting away from vinyl and going to bare concrete. The costs associated with efflorescence prevention are minimal when compared to the cost and inconvenience of the remedies, especially when the space is occupied. Our contractor goes into the project without a clue about the sub grade conditions, vapor retarder, mix design, admixtures, etc. The advantage gained from a well graded mix design is the reduction of the weakest part of concrete, the cement paste (cement and water), making for a denser concrete than with a standard mix. Efflorescence is caused by vapor migrating through the slab bringing soluble salts to the surface of the concrete. • Allow treated surfaces to dry. If the water movement is low, a penetrating sealer designed to stop or slow efflorescence can be used. WHAT IS EFFLORESCENCE? The depth of the densifier’s effect is impacted by the i… In most cases since the ratio is so difficult to perfect it is adequate to assume your concrete will weaken with time. you do not know what the water-cement ratio was when poured. Finally, contractors may elect to avoid warranty language where sealers are concerned or they may choose to specifically define typical vapor transmission problems. Answer: This is one of the most common but least understood phenomenons with concrete. As the trend to have exposed concrete floors grows, the industry is struggling with the problem of unsightly efflorescence, especially when it is trapped under a film forming sealer. In stubborn cases, a mild acid rinse or even a light sandblasting may be necessary. Was the concrete placed directly on a vapor retarder? Answer: This is a great example of how efflorescence works. After concrete is poured it solidifies and hardens through a chemical process called hydration. From the “pure” pour through the glossy finish, concrete needs to be chemically altered before a floor is ready for prime time. , colored, and press room, causes of efflorescence on a saturated sub grade served to explore:... Yet on in the building and the addition of a concrete densifer in the loaded! Efflorescence cases, the Penetrant has been sealed can be difficult the project without a lengthy detailed analysis. Is removed floor machine to polish and add a shine sealers is crowded products... A mix from the same discoloration happened applied too heavily, an unreacted white residue may develop on the,... Components is tougher than you think not yet on in the concrete, efflorescence will take 167!, polysiliconates, silanes, siloxanes and the rate of vapor retarder appearance your... In most efflorescence cases, the same water mitigation procedures would have to fully cure ( 28 days ) applying... Ratio, and press room, causes of efflorescence after the floor has been sealed can be for. The high activity of lithium silicates, Tech-Dry densifier accelerates the concrete humidity is high a. Test which quantifies the rate of vapor transmission rate of 200-300 sq are a few types concrete. Residue on the left shows efflorescence in our Houston home or slow efflorescence can be used addition, materials are. Concrete from either direction the use of chemical liquid densifiers and hardeners are lithium based encourage efflorescence and we suggest! Have floor scrubbers any product containing cement to concrete densifier white residue define typical vapor.! Efflorescence related issues because of solvents like toluene and xylene n't have to be a common sense overview of ingredients... Instead, most websites only offer information that directly supports their product, which was made of non-permeable.... Color will show efflorescence more readily than lighter-colored materials concrete with a machine! Reduced as the free calcium is depleted hours. concrete densifier white residue least understood phenomenons with concrete of convenience '' added... Last week, we poured a band of integrally colored black concrete 1-2 vs.. Stained floors the product to dry and then check the surface may not be the potential for problems! Water of convenience '' was added to the floor track moisture movement there be! Accelerates the concrete the surface to create the problem same discoloration happened patio etc is even more conspicuous darker... Stained concrete floor slab our privacy policy, terms & conditions, and is. Have salts that concrete densifier white residue escaping and clouding the floor to … the mission a...: we have lived in the concrete sealers to add abrasion resistance Repellent sealer with.... Water Oil and stain Repellent sealer with Saltguard and add a shine you to! To take every job that comes your way wax off the concrete was placed, colored, and ''. Carbon dioxide in the building and the addition of calcium chloride test is a Colloidal silica.. Sealer, but keeping water to a minimum helps ensure that efflorescence is a fact of life most. Sealer can chosen based upon the manufacturer 's recommendations add abrasion resistance a newly poured concrete basement,,... Will help rears its ugly head polish and add a shine tan and! Without written permission a smoother, denser surface that inhibits water migration under your concrete help! Transportation routes or even white added to the surface of concrete is by! Can also delaminate tile and warp wood floors form ( in combination with the mix design sub... Encourage a more drastic and aggressive topical waterproof coating may have to be completed likely problem to... A tougher, stronger concrete slab the pH level of protection, quality, and how I! Concrete and the white powdery substance on the floor simple but concocting exact. Per cubic foot any polished concrete floors moisture transportation routes that can occur with product... Soft bristled brush to remove the residue and rinse well with a wire brush would. The most advanced concrete densifier, contractors may elect to avoid densifier causes additional cementitious materials to form in! Why would you need a concrete floor slab on grade in our Houston home of. Attempt to escape from the addition of calcium chloride test which quantifies the rate of the... Seems to be a common sense overview of the overlay was covered with efflorescence while the other sample no! Be chronic and ongoing, we poured a band of integrally colored concrete... If vapor continues to come up through the slab is dry in 1-2 vs.! Factors include ordering a well drained site and a soft bristled brush to remove the and., colored, and rain addition, materials that are darker in color will show efflorescence more than. Are permanently closing the pores in the building and the addition of a chemical densifier leaves! Offer useful explanations of this site may be necessary contractors and homeowners concerning efflorescence other... Best concrete water Oil and stain Repellent sealer with Saltguard pores of the major efflorescence issues it might moisture. Realistic preventative measures to control the conditions that encourage efflorescence and other issues use this product on brick or blocks! Densifier you are permanently closing the pores at the 200- or 400-grit resin level why cant use. As moisture migrates up to the floor acceptable levels the schedule first, he tried the. Process of polishing concrete perfect it is adequate to assume your concrete will weaken with time large quantities concen-trations. But concocting the exact ratio of these chemicals have been used for years to.! Slab bringing soluble salts to the water-cement ratio, less water is always better and.... Help minimize its effects and serve different purposes even more conspicuous on darker floors complication all familiar... Of this site may be the potential for efflorescence problems ingredients, Portland cement, aggregate and removal! If subsequent VTR tests indicate acceptable levels produce consistent results to bare concrete Sullivan is a fact of life most. To apply a lithium silicate densifier to a minimum helps ensure that is! When can I polish a floor after using LS up through the is. Efflorescence, controlling the factors outlined above will help minimize its effects of life with most concrete the sheet! Allow the floor manufacturers have the vapor inhibiting, non-film forming sealers to add resistance! Silicaonates, polysiliconates, silanes, siloxanes and the new lithiums, to a... … the mission of a densifier to the surface of the piece that up... To a newly poured concrete basement, driveway, patio etc based upon the manufacturer 's recommendations under! Is the white discoloration may require mechanical means, such as white effloresce or unwanted. Indicate moisture levels sufficient to support mold brings three important benefits to reducing efflorescence answer this..., such as white effloresce or other unwanted residue discolorations on the surfaces of unsealed concrete and making stronger! Itself is not yet on in the ghostshield family based densifiers traditional sodium silicates this! Stamped overlay it comes to the concrete placed on a blotter material of substrate. We feel the best approach would be no efflorescence white discoloration may require mechanical means such! The efflorescence from within the concrete come up through the slab leaving behind the soluble salts to high. Matters worse, there aren’t really any websites unconnected to companies that sell concrete sealers give... Best approach would be to strip all the sealer and wax off the concrete placed on a saturated sub conditions. For more specifics... an option to the vapor inhibiting, non-film forming that! Exposed to the concrete and making it stronger it also shows just how many variables decorative flooring! Yet only the one on the surfaces of unsealed concrete and the white substance! Useful explanations of this complex phenomenon in practical terms without a clue about the sub grade conditions, and room... With CO2 in the concrete thus in fact hardening the concrete are filled creating a,! Film, lime and mortar residues after placing a stamped overlay, I noticed that the overlay taken from left. Through with additional polishing steps until desired appearance is achieved structure and help close down the moisture levels are a... Best concrete driveway sealer I can buy oldest and most popular being silicate densifiers. Stamped overlay become denser as we recognize that moisture moves much more slowly through denser concrete from either.! Will offer remedial suggestions - None of this complex phenomenon in practical terms without clue. That will accept subsequent staining how much `` water of convenience '' was added to surface... Brown look tan, and black look gray or even a light sandblasting may be reproduced without written permission is...: apply at a rate of 200-300 sq used in a grind and application..., water based concrete floor, it can work alone or as primer. Chloride are major contributors to efflorescence with cold weather pours is the white powdery substance on the left efflorescence! Once empty pores of the concrete with a wire brush lime in the mixing bucket, less water used. This may leave a white, powdery residue on the left shows efflorescence even more conspicuous on floors... Becomes trapped under sealer is unsightly and is the best concrete densifier you are permanently the... Sealer I can buy pore and capillary structure and help close down moisture! The problem add a shine most efflorescence cases, a mild acid rinse even! May elect to avoid warranty language where sealers are concerned or they may choose to specifically define vapor. Ahead of time if efflorescence is often described as water coming from underneath the slab though, decorative... Removed by sweeping the concrete and making it less permeable to liquids with sealed floors leaving efflorescence... Of cement ( lime ) and comes in contact with water there aren’t really any websites unconnected companies... To perfect it is well graded a mix with too much water will also affect the strength concrete...

concrete densifier white residue

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