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SurfaceFinish CD80 Colloidal Silica Concrete Hardener Densifier


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Location : Interior/Exterior
Task : Harden Densify Concrete Stone
Application : Pump Spray Roller
Surface : Concrete and Natural Stone
Base : Water Based
Drytime : 30-60 mins
Coverage : 300- 700 sq.ft/gal
Finish : Clear Liquid Concentrate Dilute 4:1

SurfaceFinish CD80 Fast-Acting Colloidal Silica Densifier & Concrete Hardener

The best fast-acting, colloidal silica densifier and hardener for new and old concrete surfaces.

Table of Contents:


  • Fast reacting-one hour or less
  • Nano particle size for deeper penetration
  • No discoloring salt deposits
  • Lower application costs
  • Greater reaction than standard densifiers
  • Produces a dust free surface
  • Increases water resistance
  • Reduces possibility of efflorescence and ASR
  • Works with low lime decorative overlay products
  • Improved abrasion resistance and life expectancy
  • Works on Green Concrete 2 -3 days’ old
  • Compatible with dyes and stains
  • Long term performance

Typical Uses

  • Surface hardening of new and old concrete
  • Dust proofing of concrete
  • Ideal for floors requiring polishing
  • Cement based overlays
  • Case hardener for pre-cast products


1 Gal Concentrate that makes 5 gallons of Ready To Use Densifier

5 Gal Concentrate that makes 25 gallons of Ready To Use Densifier


This product is concentrated and should be mixed 4 parts water to 1 part product. Shake product before mixing with water. Stir the concentrate and water together for 30 seconds with a mixing drill and paddle.


300-700 ft2 per DILUTED gallon (7.3 -17 mper liter) depending on the porosity of concrete. High porosity concrete will be on the lower end and polished low porosity concrete will be on the higher end.


Use a low-pressure pump sprayer. Be sure to shake product right before putting into sprayer. Use a conical tip that sprays .05 to .15 gallons per minute. Spray with the tip1 to 2 feet above the surface and use a circular motion to achieve an even application. Spray enough product to achieve an even look of saturation. Keep the surface wet for a minimum of 15 minutes, applying additional product when necessary to keep surface wet.

Allow surface to dry completely. This usually takes less than one hour. If concrete seemed porous on the first application, you may wish to apply a second application to achieve optimum formation of calcium silica hydrate.

When using product in conjunction with polishing, it is best to apply the product at 200 or 400 grit. If desired, CoverColor Concrete Stain should be applied prior to the application of hardener. A second application of CoverColor Concrete Stain may be used to achieve a richer color in the concrete after the SurfaceFinish CD80 has been applied and is completely dry.


This product is not a “sealer” and will not prevent staining. Use CoverShield products if you wish to seal and protect from staining

Will not accommodate dynamic movement cracks.

Do not dispose of into the water system.

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Frequently Asked Questions

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What Is A Concrete Hardener

Concrete is a tough, durable product, but it is inherently porous.  In order to reduce that porosity, we use what we call a densifier or concrete surface hardener.

These are chemicals that react with the concrete and fill in the voids.  Filling the spaces creates a surface that’s much harder.  As a result, when we polish it, we get the greatest shine possible.

If we want to seal it, we get greater adhesion with the sealers.  Densifying concrete also makes it less susceptible to staining or water ingress.

Older types of concrete hardeners that are available typically take approximately 12 hours or more to work.

Our SurfaceFinish CD80 reacts within 30 minutes to 1 hour. That’s a huge time savings for contractors or builders working on a project.

What Is SurfaceFinish CD80 Fast-Acting Concrete Surface Hardener

SurfaceFinish CD80 is a colloidal silica concrete densifier or hardener.

We use silica – as opposed to silicate – because silica is a much finer particle.  (Standard concrete surface hardener products use silicate.)

Its smaller size results in deeper penetration into the surface pores and a faster reaction with the concrete.

We provide CD80 in a concentrate that you dilute in a 4:1 ratio, so it’s very cost-effective.

And it leaves you with a much denser, much easier to use surface than the standard concrete floor hardeners available in stores.

How Does A Typical Concrete Floor Hardener Work

Store-bought concrete floor hardeners are normally lithium or sodium-based silicates that you have to apply to the surface.

You either roll it on or spread on, then you have to scrub them into the surface, making sure they react with the concrete.   Normally that reaction takes 10 to 12 hours.

Quite often, you’ll notice white spots on the surface because the metallic salts are left sitting on it for such a long period of time.


CD80 is a colloidal silica concrete densifier, and it’s smaller particles penetrate deeper within 1 hour, resulting in a much faster reaction.

And because it’s a pure silica product, there’s no metallic or salt deposits to be left on the surface long enough to leave behind spots.

The bottom line is that using SurfaceFinish CD80:

  • Your application time is much faster (by about 10 times).
  • Your clean-up time is much faster.
  • You don’t need as much product (because it’s concentrated).
  • You eliminate the labor of scrubbing and cleaning the concrete.

Why Is SurfaceFinish CD80 A Better Concrete Hardener Than Store Brands

CD80 is based on colloidal silica. It’s very fine molecules easily soaks into the concrete in 30 t0 60 minutes.
As a result, there’s no need to scrub to push it into the surface.
This fast, deep penetration into the slab saves you a lot of time and labor.

Since it’s almost 100% pure silica, it doesn’t leave the typical white salt deposits on the surface that store-bought densifiers do.
This also means you never have to invest time and labor scrubbing and cleaning off the concrete afterwards.

CoverTec also provides the product in a concentrated form, so it’s much more economical for customers.
A single gallon should be diluted in a ratio of 4:1 to make 5 gallons.  Five gallons, diluted 4:1, will make 25 gallons.

The end result is that you’ll have a slab or surface that’s much denser than what a typical floor hardener for concrete produces.

This means:

  1. You’ll get much better wear resistance.
  2. The concrete will be more water resistant and stain resistant.
  3. The surface will be easier to polish, with much less steps involved.
  4. The concrete surface will be more dust-proof and freeze-thaw resistant.

CD80 provides several benefits that standard concrete densifiers and hardeners don’t.

What Are The Do’s And Dont’s When Using A Concrete Hardener

When using any concrete floor hardener, make sure the surface is absorbent or porous. This way, the densifier can soak into the concrete.

Any contaminants that are on the surface need to be removed, either stripped or ground off.

Typically, you should look for between 200 and 400 grit surface for good penetration of the densifier.

Using a pump-up sprayer is the best way to apply the concrete hardener. We recommend spraying the product out in a fan or conical pattern.

Try to keep the surface wet for 10 to 15 minutes to make sure that you’re getting good penetration.

If using SurfaceFinish CD80, you should notice within 30 to 60 minutes that it has reacted with the concrete. There shouldn’t be any real scrubbing that’s needed afterwards.
With store-bought densifiers, penetration may take several hours longer.

Using CD80, you don’t have to worry about white spots or salt deposits on the surface.
Using store-bought densifiers, you may see spots appear as the surface dries out. You may have to do some surface scrubbing to remove them.

With CD80, you can start grinding the concrete, applying your sealer or open the floor for public use in about one hour.
With store-bought concrete floor hardeners, typically you have to wait about 12 hours before you can do anything.

So, if you’re looking for faster application and much less labor, something like CD80 would be a better product to use.

What Should You Consider When Selecting A Concrete Hardener

At CoverTec, we recommend that you look for a colloidal silica concrete densifier as opposed to a silicate product.
Silicate-type chemicals are older technology that takes much longer to react.

A colloidal silica – like SurfaceFinish CD80 – uses much finer, nano molecules that penetrate deeper into the concrete and react much faster.
This saves you a lot of time, labor and it provides a better end result as far as hardness and permeability.

Look for something that works in the dry time you need for the job at hand.
If your chosen product takes many hours, then that’s typically an older generation type densifier you are using.

Consider looking for a concentrated product… something you can dilute and get much more coverage with.
It will definitely lower your budget for the project.

If you’re going to color the concrete, it’s always good to stain or dye the surface first, then use the densifier afterward.
Doing things the other way round is not a wise plan.

Also with CD80, if you want to add more color after densification, that’s possible with a product like CoverTec’s ColorStain UV.

What’s The Best Way To Apply A Concrete Hardener Product

The old way of applying a concrete floor hardener was to use a pump up sprayer to apply the product onto the surface.

Typically, you have to scrub it into the slab to make sure that it penetrated into the concrete.

The densifier itself is a high pH, very caustic product.   As such, you’d have to wear protective clothing and eye-wear for safety.

Then you had to wait the typical 12 hours for it to react, and be ready to handle the usual issues with residue on the surface.

You’d have to scrub off that residue before you could re-open the surface for service.

Today, with something like SurfaceFinish CD80, you don’t have any of those issues.

  • You apply the product using a pump-up sprayer.
  • The colloidal silica product soaks into the concrete.
  • You don’t need to scrub it in, so you’ve eliminated that labor.
  • It’s not a harsh chemical. It’s water-based, so we don’t have to worry about using caustic chemicals.


Again, CD80 does not leave behind salt or chemical deposits, so there’s no scrubbing during or after the application.

Using a concrete floor hardener has never been easier, faster or more time and labor efficient.

On top of all this, your surface can be ready for use within 1 hour after applying the product.

Does SurfaceFinish CD80 Have A Shelf Life Or Recommended Storage Guidelines

Most concrete surface hardener products or densifiers lose their reactivity after about two years.
That’s a long life, and that’s typically what CoverTec recommends with SurfaceFinish CD80.

It’s water-based, and as long as it’s stored in a cool place and doesn’t freeze, you can keep it up to two years and re-use the product.
This also means that there are no harmful VOC’s.

It’s not caustic. That’s a big advantage over standard concrete surface hardeners with a very high pH.

It doesn’t leave any dust or metallic salts on the surface, which eliminates any respiratory problems for the public.

The bottom line is that CD80 is a cleaner, safer and much less corrosive product to use.

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