The Best Concrete Densifiers for Stone and Concrete


With all of the advancements in the concrete industry, concrete densifiers stand out and are amazing products with important benefits. However, concrete densifiers are not only confusing for those outside of concrete industries but can even cause some confusion for those within the industry as well. This article will discuss in easy to understand terms what a densifier is, how it works, and selecting the best Serveon Sealants densifier for your project.


What is a Concrete Densifier? 

A concrete densifier is a topical, water based chemical hardener. It is commonly sprayed on top of a concrete product or concrete slab after placement.  If polishing the slab, it is used during the process of refinement. Regardless if the slab is a poured deck or is polished or left unpolished, using a densifier is an economical way to add strength, endurance, and longevity. It also make it less permeable to stains.

Concrete densifiers are used as part of the refinement process of concrete polishing but are also widely used on unfinished concrete slabs, concrete tiles, and poured pool surrounds and patios. Concrete densifiers can be used on old concrete as well as new concrete. This product acts as a pore filler and increases the surface density of the concrete.

When applied, the densifier deeply penetrates the concrete, creates a chemical reaction, and produces a byproduct that fills every pore. This outcome hardens the concrete surface reducing pitting. It increases the surface durability of new concrete significantly compared to concrete surfaces that are not treated with a densifier. The product hardens old concrete, decreasing wear and the effects of weather.

How Do Densifiers Work?

During the process of curing, concrete slabs or anything made from concrete like pool decks and patio decks produce a byproduct called free lime. The free lime remains in the concrete long after it has cured. Free lime is calcium carbonate, which when it reacts with the concrete densifier produces a stronger substance. Because products made from concrete are porous by nature, using a densifier is a great way to make them less porous and stronger overall as a finished floor or driveway surface.

When the concrete densifier reacts with the free lime, calcium-silicate-hydrate gel forms. This gel is a very dense and hard crystal which forms a continuous layer. The chemical reaction that is produced binds the concrete and densifier together, making the slab or concrete sections stronger and more durable to wear than it was before treatment. Another added benefit of treating concrete with a densifier is that it stops it from dusting (a continual natural occurrence with concrete over time). 

Benefits of Densifying

Densifying for years has been associated with commercial building applications where polished concrete is preferable for many buildings, factories, and other facilities. Due to its strength and resistance to wear, concrete densifiers have been an ideal accessory for polished floor surfaces in a variety of settings including stadiums, hospitals, government buildings, airports, and factories. Densifying increases the floor’s resistance to moisture, chemicals, oil, grease, and abrasion.  It also takes much longer to show wear from pedestrian or vehicle traffic and increases light reflection. 

For concrete pools surrounds and patios all the same benefits apply. The concrete surface is made much stronger and resistant to wear, chipping and cracking. Because it is now less porous, it is also more resistant to stains. Importantly, densifying is a permanent application.

For decorative concrete tiles, densifying adds years of wear and reduces chipping. 

Serveon has advanced densifying sealers for natural stone. These densifying sealers restore decaying and flaking stone and reduce the effects of deterioration for years.

Which Serveon Densifier is Right for Your Project?

Selecting the right professional Serveon Densifier for your patio or pool surround’s unique circumstances is important. Over the last 15 years our densifier applications have made it through hurricanes and floods, scorching hot summers and freezing winters. We believe they are the best in the industry.

Importantly, some of our consolidator/densifiers also contain chemicals that repel water and eroding pool salts dissolved in water. These chemicals penetrate into the surface where they chemically react to form a long-lasting hydrophobic barrier within the pores. Most of Serveon’s densifying sealers also inhibit efflorescence from rising to the surface.

Concrete Densifiers

SD500:  Consolidating/densifier is a formulation of penetrating lithium and other silicates for new and existing concrete. They react with concrete to produce insoluble calcium silicate hydrate within the concrete pores. SD500’s cutting-edge technology easily makes it the premium hardener, densifier and sealer for concrete surfaces old or new. Click here to see more.

SD600:  The Shell Densifier is identical to SD500 plus it waterproofs. SD600 integrally waterproofs, densifies, strengthens and preserves concrete of any age at any point during the concrete’s lifespan. Click here to see more.

Factors for great sealing experience

Factors to make a great sealing experience

Make your installation an inspiration, not a lesson!


Although stone is typically hard, some are soft and subject to decay; over time all stone and concrete is vulnerable to weathering plus wear from foot and vehicle traffic, and if around pools from chlorine and salt erosion.  Sealing can protect the surfaces from wear, weather, damage, deterioration, staining, discoloring algae and prolong the life by strengthening and shielding keeping it looking clean and new for years.

Over the years we have learned a few “Do’s and Don’ts” when it comes to sealing. We would like to pass along these tips to make sure your installation is trouble free.

Application Do’s and Don’ts                                

BE SURE TO PROTECT passersby, building occupants, people, vehicles, property, plants, painted surfaces and other surfaces from accidental overspray, residue, splash, fumes and especially wind drift.  Wind drift carrying spray can carry sealers to unintended areas.

ALWAYS CLEAN THE SURFACE PRIOR TO SEALING:  Remove dirt, leaves, loose particles, loose stone, grease and stains before application.  This is usually best done by power washing.  Whatever is not removed will be permanently sealed onto the surface.

DO NOT APPLY OVER PREVIOUSLY SEALED AREAS: If unsure if application area has been sealed before, test a small area.  If the sealer does not absorb or beads, this indicates prior sealing or too dense a substrate; applying the product over a previously sealed area can result in a white haze or oily film forming on the surface that is difficult to remove.

SURFACE MOISTURE: For most sealants, be sure no water is applied, power washing etc., or heavy rain occurs for a minimum 24 – 48 hours prior to application. If the area to be treated has been underwater for long periods such as a waterfall or the backside of the substrate is adjacent to water, additional drying time will be necessary.  If unsure of substrate moisture content, test with a moisture meter.  The test area and application area for most Serveon sealants must be THOROUGHLY DRY before application.  Applying the product over an area that is not dry will usually result in a white haze forming on the surface that is difficult to remove.

DO NOT apply sealant products on non-porous, very dense stone, glazed tile or glazed/fired brick. Most products will not absorb into these materials.  Test a small area. If the product does not absorb and stays on the surface after 3 – 5 minutes the substrate is non-compatible, and the excess sealant should be removed.

SURFACE TEMPERATURE: Do not apply if the surface temperature exceeds 95o F (or) falls below 50o F. For most products, the ideal application temperature is a surface temperature of 55 to 90oF.  In summer months, stone exposed to direct sunlight can be substantially hotter than the ambient temperature.  Sealants need time to penetrate and be absorbed. High heat can evaporate the liquid carrier too quickly leaving unabsorbed chemicals on the surface. If allowed to dry the dried chemical can be difficult to remove. If unsure of surface temperature, test with a inexpensive Thermo Laser Meter.

ALWAYS TEST BEFORE SEALING: Test a small area of each different surface to be sealed for penetration (the product is absorbed into the substrate), possible color change and desired results before starting the overall application.  Test with the same equipment, surface preparation and application procedures the job will be done with.

REMOVE EXCESS PRODUCT:  After product has absorbed, wipe or blow off any excess product remaining on the surface, do not let product “puddle” or pool in low areas and dry.

EACH PRODUCT AND SURFACE IS UNIQUE:  That’s why we encourage you to get the specific Data Sheet and Application Guide for your product.  Why? Because silicone products are different than acrylic products, water-based products are different than solvent-based products and dense surfaces are different than porous surfaces.  Please visit our website at

All About Efflorescence



Efflorescence is a crystalline deposit that usually appears on the surfaces of bricks, masonry or concrete and is visible to the naked eye. Aesthetically it takes the appearance of a white powdery/crusty substance that detracts from the appearance of the substrate.

Limestone, concrete and brickwork (collectively called material) provide aesthetically pleasing structures. Typically, on new material, a white crystalline deposit will appear on its surface. These deposits are usually water-soluble salts referred to as efflorescence. Although aesthetically undesirable, efflorescence is usually not harmful to these materials.

This article describes the basic mechanisms of efflorescence, including possible sources of salts and water, providing a basic understanding of the phenomenon of efflorescence.  This will help in understanding how Serveon’s sealant products prevent or minimize its occurrence.

Limestone: is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3) and lime or Calcium Oxide (CaO). It often has variable amounts of silica in it, as well as varying amounts of clay, silt, and sand. Limestone is subject to efflorescence.

Concrete/brickwork/mortar: Concrete is made using Portland cement, and cement is made from limestone using a process called calcination—where limestone is heated with other materials to 1450 degrees Celsius, resulting in a hard substance called clinker. The clinker is then ground into a fine powder to make cement.  Any material containing Portland cement can result in efflorescence.


There are many aspects of efflorescence, some complicated. It is difficult to predict if and when any will appear. Simply stated however, efflorescence occurs when water containing dissolved salts is brought to the surface, the water evaporates, and the salts are left on the surface. The salt solutions may migrate across surfaces of the material, between the mortar and material, or through the pores of the mortar or the material. Water soluble salts are generally characterized by the presence of calcium sulfate, calcium carbonate and sodium chloride.

There are certain simultaneous conditions that must exist in order for efflorescence to occur:

  • Soluble salts must be present within or in contact with the material. These salts may be present in mortar ingredients, backing materials, trim, adjacent soil, etc.
  • A source of water must be in contact with the salts for a period of time sufficient to dissolve them.
  • A pore/capillary structure must be present in the material that allows the migration of salt solutions to the surface or other locations where evaporation of water can occur. A driving force, such as a temperature or humidity gradient (evaporation) or in severe cases, hydrostatic pressure, directs moisture through the pore structure.
  • If any of these conditions are eliminated, efflorescence will not occur.


Concrete is made using cement, and cement is made from limestone. Consequently, all concrete paving’s contain a quantity of lime, or Calcium Oxide (CaO) as does limestone. Calcium Oxide is water-soluble. It dissolves to form Calcium Hydroxide. The soluble Calcium Hydroxide can migrate to the surface of the material, whereupon it has the opportunity to react with Carbon Dioxide (CO2) in the atmosphere and water to form Calcium Carbonate, which is not soluble.

The carbonation of the Calcium Hydroxide results in the insoluble Calcium Carbonate being deposited on the surface of the material while the water simply evaporates away. It is the Calcium Carbonate that forms the white deposit that is the most visible indicator of ongoing efflorescence.

While the Calcium Carbonate is insoluble in water, it is not permanent and gradually reacts with more Carbon Dioxide and more water to form Calcium Hydrogen Carbonate, more commonly known as Calcium Bicarbonate, which is soluble.

The problem is that this transition from insoluble to soluble is much slower than the preceding transition from soluble to insoluble, so there is a ‘stockpiling’ of excess insoluble material, which is the white deposit seen on the surface of most pavers.


While the vast majority of the Calcium Oxide (what causes efflorescence) will come from the material itself, it may also be present in the laying course material (what a paver is laid on).  This is especially true where a mortar, concrete or other cement-bound bed is used. Similarly, water comes not only from precipitation, that is, rain and snow, but also from the ground beneath the material, from the atmosphere (as dew), from washing the car, or from watering the lawn, as well as being a vital component of the original material as is the case with concrete and pavers. The Carbon Dioxide is ever-present in the natural atmosphere, but there may be environments where levels of CO2 are higher or lower than normal due to local natural phenomena such as vegetation.


As mentioned in the previous paragraphs, the white bloom is gradually converted to a soluble compound that is usually washed away by the weather or pressure washed. However, there are other factors that act to reduce or remove the visual impact of efflorescence.

At a point, the amount of salts in the material are used up over time.  With no salts there is no efflorescence.  Finally, the tiny pores and voids within the material matrix through which the soluble Calcium Hydroxide is transported eventually can become plugged with deposits of the insoluble Calcium Carbonate. This action effectively blocks the escape route for the Calcium Hydroxide and ‘locks in’ any further reactions, forcing them to take place below the surface and, conveniently, out of sight.  Blocking the capillaries that allow the calcium hydroxide to be transported to the surface is the key to preventing efflorescence.


There is a wide range of different sealants, but for the purposes of this discussion, they can be divided into two types: those that form a ‘film’ on the surface, normally acrylic based sealants, and those that penetrate and form a more considerable barrier extending several millimeters into the material. Film forming sealants are generally ineffective against efflorescence as the process continues and the carbonate material is deposited beneath the thin layer of sealant. Penetrating sealants can block the pores of the material near the surface, thereby limiting the absorption of water and carbon dioxide, and the egress of calcium carbonate, which remains trapped within the material.

We believe Serveon’s sealants are the most effective sealants available at preventing efflorescence.  This is because the unique formulations are proven to both penetrate and block the pores and capillary routes taken by the Calcium Hydroxide to reach the surface while at the same time, preventing water being able to be absorbed into the material.  Restricting the amount of water limits or prevents the ability of the salts to be dissolved. Undissolved salts cannot create efflorescence.



Serveon has three water-based sealants that prevent efflorescence.  NS800, RS800 and NS200.  Of the three, NS800 is the most effective.  All three of these sealants do not form strong bonds with sanded/unsanded grout and mortar.

Treating the surface of the material and any adjacent mortar or grout will normally prevent the occurrence of efflorescence.  Treating all sides of the material is the most effective prevention.  Untreated mortar or grout where also present is a source of efflorescence and must also be treated.

Material, as used here, means “porous”, cement, limestone, etc.  Application, however, can depend on the surface: honed, polished or natural will absorb differently.  In all cases it means saturation application(s).  Porous material when viewed closeup contains large areas to be covered and will normally absorb a lot of sealant. The more sealant applied, the more effective the blocking becomes. Please see the applicable product Data Sheet and Application Guide for specific guidelines.


Of the three conditions that cause efflorescence, moisture is the only one that can be controlled. Recurrent efflorescence indicates a chronic moisture problem. Steps should always be taken to minimize the amount of non-precipitation water. Where severe water issues exist, it can create hydrostatic pressure that can rupture the blocking bonds.  There are no short cuts to preventing efflorescence. When proper drainage is not present it can cause efflorescence issues, although reduced, even in sealed materials until the salt source is used up or the water source is eliminated.


Efflorescence can be removed with either of Serveon’s cleaners, CL500 or CL750.  In both cases apply the cleaner, let sit for 1-2 minutes, while sitting agitate with a stiff plastic bristle brush then thoroughly rinse with water.  With some stubborn deposits, the procedure may have to be repeated.