Manufacturers of Concrete Patch Products

Some of the manufacturers, besides making great products, also have very informative product literature. For example, the Quikrete Company has a book that may interest you. It is called Build and Repair with Concrete. The Portland Cement Association (www.cement.org) also has a huge amount of excellent literature on concrete. Go to the bookstore on their web site. Many of the publications are available for free download.

At the same time, consider ordering a book called The Homeowner's Guide to Building with Concrete, Brick & Stone. This is a great book that covers building new masonry projects as well as maintenance and repair. No homeowner should be without this book!

• Abatron, Inc.
  • Abocrete - concrete repair product
    Aboweld - epoxy repair compound
    Abocoat - concrete coating product
• Quikrete Companies
  • Vinyl patching compounds, bonding adhesives, concrete acrylic fortifiers, concrete cleaners (acid free), quick setting cement & more.
• Bonsal Sakrete Concrete
  • Complete line of concrete patching compounds and repair/ maintenance products.
• Tamms Industries Company
  • Concrete repair admixtures, bonding agents, and sealers.

Other companies who make concrete repair products:

• • Ardex Engineered Cement
    

• • AVM Industries
    

• • DAP
    

• • Kryton Intl.
    

• • Maxxon Corp.
    

• • Quality Systems Inc. (QSI)
    

• • Sinak Corp.
    

• • Sto Corp.
    

• • United Gilsonite Laboratories
    

• • White Lightning Products Inc.
    

• • W R Meadows
    

• • Xypex Chemical Corp.

Concrete Crack Repair | Here's a normal concrete shrinkage crack in a basement slab. One year after the slab is poured you can start to think about repairing it. You have several options. See below. Copyright 2019 Tim Carter

Concrete Crack Repair Tips - It's Detail Work

What Concrete Crack Repair Options Are Available?

You have several options to repair concrete cracks:

• inject the crack with epoxy
• fill it with gray ceramic tile grout
• patch with expanding hydraulic cement

What is the Best Epoxy To Use?

The best epoxy for concrete crack repair, in my opinion, is made by PC Products.

This is the magic epoxy that fits into a regular caulk gun. I've used it with great success. CLICK on THE PHOTO NOW TO HAVE IT DELIVERED TO YOUR HOME.

As you might imagine, the prep work before installing your patching material is the most important part of the job. This is really true of most building and remodeling jobs.

Why is Prep Important?

The concrete surfaces need to be clean and free of all dust and anything else that will interfere with the bonding of the repair material to the sides of the crack.

Is Epoxy the Best Material for Concrete Crack Repair?

Epoxy is a fantastic repair material. Most are quite thick so the crack needs to be about 1/4-inch wide for you to be able to inject the epoxy with ease.

You can buy a durable epoxy that has a special mixing nozzle. I demonstrate it in this video:

What is the Caulk Gun in the Video?

Here's the fantastic caulk gun I used in the video. It's designed to give you lots of control when you squeeze the handle.

My caulk gun is just like this one. Once you use a gun like this, you'll throw away the one you have that has the click notches. They're pieces of crap. CLICK on THE IMAGE NOW TO ORDER THIS GUN.

How Do You Repair Cracks and Holes on Flat Concrete?

You can use sanded ceramic tile grout or Portland cement mixed with fine or medium sand to repair large cracks and holes in concrete.

Most repairs on flat surfaces, such as a driveway, patio or sidewalk, consist of filling a depression or hole. The hole usually has tapered sides.

These tapered edges can cause real problems for the long term durability of the patch. The patching compounds thin out at these spots and can easily peel or fail. The result is an unsightly second area to patch the following month or year.

How Do You Prevent the Failure of the Patching Compound?

I have had the best success patching when I alter the sides of these holes. This can be done with either a chisel and a hammer or a saw equipped with a masonry blade.

NOTE: Always wear eye protection and/or ear protection when doing this type of work. Small pieces of concrete, dust, metal or masonry blades can cause severe eye injury. Hearing loss is a real threat as well.

The challenge is to remove the taper from the edges of the hole. If you are successful, the finished edges will be 1/8 inch thick or so instead of tapering to a feather edge.

SECRET TIP: Mix pure Portland cement with water to the consistency of latex paint. Brush this into the crack or the hole immediately before filling with the patching material. Do NOT allow the cement paint to dry. Work FAST.

How Do You Mix the Patching Materials?

Always follow directions. Most compounds should achieve the consistency of cake icing or a very thick gravy (don't eat these compounds!) Only mix enough compound that you can apply in 15 to 20 minutes.

How Do You Apply the Patching Material?

When using water-based repair compounds, wet the surface to be patched, if you are not using a bonding agent. If using a bonding agent follow directions carefully.

For deep repairs, consider installing hardened nails in the depression. For extra deep repairs, drill a 1/2 inch diameter hole and pound a 1/2 inch piece of reinforcing steel into the hole. These items will help hold the patch in place. Be sure that these pieces of steel are at least 1/2 inch below the top of the patch.

Use a finishing tool (magnesium or wood float, steel trowel, etc.) to finish your patched area. Finishing is an art and takes practice. You may have to wait a few minutes until the patching compound begins to stiffen to achieve the desired results. Practice in some out of the way spot, if in doubt.

When you are satisfied with the patch, cover it with a piece of plastic. Weight the edges of the plastic so it will not blow away and so air cannot blow underneath the plastic. This is very important!! Keep the plastic in place for three to four days.

What are the Best Weather Conditions to do Concrete Crack Repair?

Sunny, hot, breezy weather is the worst time to do this type of work! Many people think it is the best time. These conditions cause the patching compound to dry out too fast. Fifty-five degree F weather, overcast and damp is a great time to do this work. If you insist on doing it in warm weather, do it in the early morning. Then, shade the repairs so the sun can't hit them.

Don't attempt to repair concrete in freezing weather. The patches will readily freeze and fail. Use common sense.

Time to Work

Let's get to work! Now that the concrete surface is clean and all loose material is gone (you did do that didn't you?), we just need to provide the forms to create crisp lines on the sides of the slab.

You can do this with 3/4 inch thick pieces of 1x4, or 1/2 inch pieces of plywood which have been ripped cleanly and evenly with a table saw. Hold the edging up to the desired thickness of your overlay. A gauge block works great for this! What's that? Well, let's say you are doing a 1/2 inch overlay.

CLICK this image and listen to the first call on the podcast. I talk to Vic about how he can do a concrete overlay and save THOUSANDS of $$$. Copyright 2018 Tim Carter

Cut a 4 inch by 4 inch piece of plywood and set it on the old surface at the edge. Hold your form board flush with this little block, nail the form board to a stake to secure the established height and you are ready to rock and roll.

Pre-existing Cracks

Undoubtedly, your concrete surface may have some original control joints or other cracks. These must be marked on the sides of the forms. Why? Because these cracks WILL telegraph through the new overlay. You need to install your own new control joints with a standard jointing tool to make a nice new line!

You can also take care of this condition by pouring the overlay in sections. Simply do one block at a time. Install a form board the same height or depth of the overlay in between the two side form boards. This will produce a nice crisp line for you as well.

The Materials

Your material requirements are simple and inexpensive. You need Portland cement, fine and coarse sand, and possibly some pea gravel. You will need pea gravel if you intend to do an overlay thicker than one inch.

The cement and fine sand are used as your glue. The cement, coarse sand, and possibly pea gravel are used for the overlay material.

If you are doing a thin overlay, less than one inch, moisture loss from the thin overlay is critical. If water leaves the mixture too quickly, the overlay can be subject to plastic shrinkage cracks and 'curling'. The overlay can actually delaminate from rapid moisture loss.

One of the ways the material looses water is by suction from the old concrete. In other words, the concrete sucks the water from the fresh overlay. To avoid this, the old slab should be wetted and kept wet for 12 hours before you start. You can do this by wetting the slab and covering it with a plastic sheet. Be sure to remove standing puddles before starting to work.

The Mixtures

You don't need fancy admixtures or bonding agents to get great results. Good old cement will do just fine. The mixture for your overlay consists of coarse sand, cement and possibly gravel. You want a minimum of seven bags of cement for each cubic yard of overlay you apply. For purposes of volume measurement, this equates to three parts sand to one part cement. Of course, if you add more cement, say 2.5 parts sand to one part cement, your chances of success will do nothing but increase.

If you are doing an overlay that contains gravel, you would mix two parts gravel, one part sand and one part cement.

The cement paint is easy. It is a one to one mixture of fine sand and cement. Of course you can also go a little heavy on the cement to get a greater bond. You mix these two ingredients dry and then add water to make a slurry just like a rich paint. Only mix what you can use in one hour or less. Remember, it is easy to mix up a quick batch!

Consistency

Remember earlier when I said that water is the primary cause of concrete failure? Well, don't goof up! I would like to see you mix up your overlay material so that it resembles a somewhat stiff mortar. If you can readily pour it from your wheelbarrow and it flows like a bowl of clam chowder soup, too much water!!

I would like to see the consistency of thick oatmeal. Remember it can't be so stiff that you can't easily spread it.

Ten Feet at a Time

Let's work in sections. Don't try to tackle the entire driveway at one time, especially if you have not finished concrete before. Let's just do 10 feet or so at a time, or work block to block on top of the existing surface. We already talked about recreating lines and how to form at a line.

Remember that as you mix each batch, that batch has a separate setting time than the one before. It is kind of like putting rolls in an oven at different times. They will all brown at different times! You don't want to get caught trying to mix or install a new batch while the other one is ready to finish!

Blending Your Overlay

Earlier we talked about different levels where the bad surface meets a good one. If you have to taper your overlay to meet a surface that is flush, it is not a problem. The overlay material without pea gravel can be applied successfully in a layer as thin as 1/8 inch! Just make sure that it has a good amount of cement in it. If you dilute this thin layer with water, it will surely fail.

If you are doing an overlay that contains pea gravel, you will need to mix a batch of overlay that just contains sand. This overlay will be blended into the gravel batches as you get close to the surface you are working towards. In other words, you may wish to start to taper your overlay four feet away from the flush surface. The last four feet of overlay will then contain lesser and lesser amounts of gravel. The final foot may be just the pure sand mix.

The Paint

OK, the stuff is mixed and we are ready to go. Well, did you have your helper mix up a batch of cement paint? Great! Is the surface damp? Wonderful! The helper should start to paint the old surface just ahead of the individual who is applying the overlay. Don't put paint down that can't be covered with overlay concrete within five minutes!

Screeding & Finishing Tips

Use a straight 2x4 or other board that will stretch beyond each form board by one foot. This is how you level off the overlay material. Start at one end. Using a back and forth motion like sawing a piece of wood, slide the board over the form boards while you advance it like a bulldozer. Fill in any low spots as you go.

Within a matter of minutes, maybe a half hour, the overlay mixture will get fairly stiff. You can imprint it with your thumb say 1/16th inch. It is time to finish. Use a wood or magnesium float or a broom to give the slab your finish. Brooms are easy. You just lightly drag it over the material. Floating requires some technique. Don't press too hard. Use a circular motion and lift the leading edge of the float so it doesn't dig in.

After you are finished, spray the surface with curing compound or cover it with plastic for four to five days. Rapid moisture loss will weaken the overlay! The following day, feel free to lift the plastic and mist the concrete. Keep the top surface damp and you will have an awesome surface!

Curing Surface Problems

Often, the concrete below the surface is in good shape. The surface peels away because the cement which holds the sand and gravel together was very likely diluted by the installer.

This happens when the finisher sprinkles water onto the concrete surface or floats the bleed water back into the concrete while working it. This extra water simply dilutes the cement in the upper surface.

CLICK this image and listen to the first call on the podcast. I talk to Vic about how he can use a concrete overlay to save THOUSANDS of $$$. Copyright 2018 Tim Carter

With less cement present, the concrete is very susceptible to damage by ice formation or pressures exerted by salt crystallization. With enough cement present in all parts of the concrete, it can withstand years and years of snow, ice, salt, etc. That is a proven fact.

The Fix

Do you drive the Interstate highway system? If so, you probably have seen bridge resurfacing/restoration projects happening.

Here in Cincinnati, workers have been applying a one to two 2 inch concrete overlay on top of the old concrete surface. No doubt they use specialized bonding agents and a special mix due to the abnormally high traffic loads and abuse the bridges receive.

You, however, can redo your driveway in a simple fashion that will last for many, many years.

Want perfect concrete work? Find a pro by using my Concrete Work (Sidewalks, Driveways, Patios & Steps) Checklist. I offer a 100% Money Back Guarantee.

Adhesion - The Key

The concrete overlay you are about to install will succeed if it adheres or sticks to the old surface. If it does not, it will simply peel like your existing surface. Regular Portland cement is an excellent glue or adhesive. Just think - had the original concrete mason/finisher done his/her job, the Portland cement in the original mix would be working just fine.

Adhesion of the new overlay to the old concrete has both a physical and chemical aspect. The Portland cement crystals grow into and chemically bond to the clean, old cement matrix. Mechanically, the greater the surface area of the bond the more crystals will grow and create greater adhesion. This simply means that the rougher the surface, the better the bond!

Thus, it is to your advantage to remove all loose concrete, dust, etc. from the surface. A pressure washing to blast away concrete that appears sound but actually isn't is not a bad idea!

Grease and oil stains will interfere with adhesion. You must remove them using soap, solvents or a combination of the two.

Once all of the loose material and contaminants have been removed, wash the surface to be repaired with soap, water and a stiff broom. We want it squeaky clean. Rinse to remove all soap, dirt, dust, etc.

The Overlay - How Thick?

The thickness of the overlay is critical. It is often dictated by conditions other than the slab you are going to repair. In other words, the slab may abut a garage slab or city sidewalk. The current levels of these two surfaces may be level! What do you do then? I'll tell you in a moment.

I have successfully installed overlays that are only 1/2 inch thick. These can easily be accomplished by a novice homeowner. The thin overlay allows a large area to be covered by a minimal amount of material. For example, if you install a 1/2 inch overlay on your driveway, and your driveway measures 648 square feet, you only need one cubic yard of overlay material! That is not much. Your original driveway probably required 10 times as much material.

Concrete Overlay Literature Sources

The following two organizations have the absolute best information on all aspects of concrete and concrete installation. Each has an online Bookstore listing all of their publications. Their literature is authoritative, easy to understand and user friendly. Check it out!

• American Concrete Institute (www.concrete.org)
• Portland Cement Association (www.cement.org)

Residential Concrete Installation Manuals

Many people are unaware of the fact that concrete is a sophisticated and technical building product. I feel this is partly because three of the four basic ingredients of concrete are so common: sand, gravel and water. The fourth ingredient, cement, is where the science and technology come into play. This key ingredient allows concrete to go from a liquid or plastic state to a solid compound in just hours time. It is a wonderful transformation that, when done properly, can yield a product which is extremely durable.

However, homeowners and trades people often fail to properly install concrete. I think that this is due, in large part, to the vast amount of misinformation which has been passed along concerning concrete. Fortunately, there is an enormous amount of clearly written information dealing with concrete. Much of it is available at public libraries. However, probably the most concentrated source of high quality concrete information is available from The Portland Cement Association (PCA - http://www.cement.org).

The PCA is "an organization of cement manufacturers whose mission is to improve and extend the uses of Portland cement and concrete through market development, engineering, research, education, and public affairs work". They have been around for years and are considered by many to be one of the most authoritative sources of concrete information in the USA.

Want perfect concrete work? Find a pro by using my Concrete Work (Sidewalks, Driveways, Patios & Steps) Checklist. I offer a 100% Money Back Guarantee.

The Portland Cement Association has an online catalog listing all of their publications. Many of them are written so that a layman can understand them. You will be amazed at the number of publications available. Some are small five to ten page pamphlets, and are available for free download in PDF format. Others are full blown books. The photos and illustrations are excellent. Following is a partial listing of publications which would be of great use to homeowners. I've listed the item number and its title.

• LT167 THE CONTRACTOR'S GUIDE TO QUALITY CONCRETE CONSTRUCTION

• IS174 CONCRETE FOR SMALL JOBS
• LT209 GUIDE FOR CONCRETE FLOOR & SLAB CONSTRUCTION
• LT202 RESIDENTIAL CONCRETE
• EB122 CONCRETE FINISHER'S GUIDE
• SP038 HOMEOWNER'S GUIDE TO BUILDING WITH CONCRETE, BRICK & STONE
• EB001 DESIGN AND CONTROL OF CONCRETE MIXTURES
• IS177 CONCRETE SLAB SURFACE DEFECTS: CAUSES, PREVENTION, REPAIR

08/2008

Concrete Strength

Not all concrete is the same. The design strength of concrete is a function of the quantity of cement used when it is mixed. The more cement that is used, the higher the strength of the finished product, as long as you place, finish, reinforce and cure the concrete properly. Thus, the final strength of the concrete really depends upon what is done after the concrete is unloaded from the truck! Many people are unaware of this responsibility. However, certain applications require different minimum strengths. For example,exterior slabs (driveways, patios, sidewalks, steps, etc.) should be a minimum 4,000 PSI strength. The PSI refers to pounds per square inch, or its compression strength. As the number gets larger the concrete becomes stronger.

Thickness

The performance of a slab is directly related to its thickness. The thicker you pour a slab the stronger it will be. In fact, increasing the thickness of a slab from four to five inches increases the strength dramatically.Thicker slabs can handle more weight and are better able to bridge depressions which may form due to soil settlement. A thicker driveway slab will possibly be able to handle that once a year heavy delivery truck. When you consider the long term benefits, the slight extra cost to increase the thickness is well worth it.

Cracking

Most homeowners are shocked when I tell them that concrete is supposed to crack. In fact, I guarantee that it will crack in a majority of instances. The reasons are really very simple. Concrete cracks can usually be blamed on one or more of the following: cracks caused by shrinkage related to the curing or drying process, cracks related to expansion and contraction induced by temperature changes, cracks related to concentrated heavy loads, cracks related to poor, uncompacted sub-grade conditions, cracks due to rapid water loss prior to the final finishing stage. These all might sound complicated, but in reality they are not.

Want perfect concrete work? Find a pro by using my Concrete Work (Sidewalks, Driveways, Patios & Steps) Checklist. I offer a 100% Money Back Guarantee.

Concrete shrinks when it drys, just like many things. Clothes shrink, wood shrinks, and concrete shrinks. Concrete is similar to wood with regards to shrinkage. As a piece of wood dries, it shrinks. The wood fibers pull closer to one another in response to the loss of water. Eventually a weakness develops between a 'row' of fibers, and a crack or a split develops. This is exactly what happens to concrete. The crystals of concrete are actually pulling away from one another. This pulling or tensile force is enormous and will crack the slab. The rate of shrinkage is very close to 1/16" per ten feet. So, if you poured a 100 foot long slab it will shrink nearly 5/8"! That's a lot! The trick is to anticipate this shrinkage and attempt to force the concrete to crack where it will look the least noticeable.

The installation of control joints every 10 feet in large slabs will generally account for this shrinkage. A control joint is an induced crack point. You may notice them as tooled lines that occur on a regular basis in sidewalks and driveways. These tooled lines should be deep enough (1/4 of the thickness of the slab) so as to create a natural weak spot in the slab. Isolation joints are points where concrete meets up against something that for all intents and purposes will not move. These joints are made of a material that will react to the expansion and contraction of the slab. These materials are sold under different names such as expansion paper, homasote, fiberboard, etc. It should be installed in strips the same thickness as the slab which is being poured.

Reinforcing Steel

Steel is an inexpensive and user friendly material. Concrete and steel work very well together. The addition of steel to concrete increases concrete's strength enormously. Concrete has very little tensile strength - that is, it can be pulled apart easily. Steel, on the other hand, has tremendous tensile strength. So, if you add enough steel to concrete, it is virtually impossible to pull it apart. Cracks commonly occur in concrete due to its low tensile strength. So, adding steel helps to minimize cracks that might develop as a result of tension. Cracks that do develop often will remain as hairline cracks. If the steel is large enough (1/2"reinforcing rods), frequently there will be no vertical displacement between the two cracked sections.

Steel is very inexpensive. I can purchase 1/2" rods locally for $0.15 a linear foot. Using this number, you can purchase enough steel for a 10 x 20 foot slab for less than $40.00!! I calculated that sum by creating a mat of steel rods, two feet on center both directions, one foot in from each edge. That matrix creates a very strong slab. Would you be willing to pay an additional $40 in materials to significantly increase the strength of your slab? I thought so. An experienced mason with a helper can install this steel in just several hours. It is well worth the price.

You can also install welded wire mesh in slabs. This material is usually available in two sizes, 21# and 42#. The mesh is generally five feet wide and is comprised of squares six inches on a side. The 21# mesh is constructed of steel wire approximately 1/16" thick. The 42# mesh wire is close to 1/8" thick. Mesh is very effective at strengthening slabs. Although I personally prefer steel rods, mesh is a good alternative for those who feel they cannot install the heavier steel rods.

Please take some time and do additional reading concerning concrete. I guarantee that you will be amazed at how much science and technology is involved. This added knowledge will enable you to spot the informed professional that you intend to hire for your next job. Ask him or her some direct, pointed questions. Ask them if they know what the PCA is. See how they respond. Hopefully, you will be able to locate an individual who can answer a large majority of your questions correctly. Good reading and good luck!

Remember to check to see if the sealant will discolor your existing concrete. Most of them will not. Some of the acrylic sealants look milky colored when applied, but will dry completely clear. However, be sure to verify this with the manufacturer before applying to your concrete!

Manufacturers of Concrete Sealants

• Saver Systems
• W.R. Meadows, Inc.
• Abatron, Inc.
• Metalcrete Industries, Inc.
• Sika Chemical Corp.
• Chemprobe Corp.
• Thompson's Water Seal
• Conproco Corp.

Related Articles:  Deicing Salts And Concrete, Concrete Sealants, Concrete Life Maximized

08/2008