It is possible to minimize stains on concrete if you make the surface smooth using a steel trowel, but trust me, this is very slippery! I do NOT recommend steel trowel finishes for concrete that has the possibility of getting wet on a regular basis.

The better method is to simply apply a clear sealer or liquid repellent. There are many types available but I feel that those containing silanes and siloxanes are among the best. These chemicals partially fill the pores of the concrete matrix and simply don't let the water and oil molecules pass through and into the concrete. The liquids stay on top of the surface.

Many of these products are available at specialty concrete supply stores. Most major cities and towns have these. Open your Yellow Pages and look under Concrete Supplies. Beware of heavily advertised consumer products. These often contain silicones or other similar chemicals. Avoid these if possible because some of these products are film formers and simply lay on the surface of the concrete. Some of them don't allow the concrete to breath. This is a bad thing especially if you live where the temperature drops below 32F. Water vapor from the soil passes through concrete and the film formers can block this movement resulting in damage to the concrete surface.

The following products are great for minimizing oil stains on concrete:

• • Aquapel / L & M Construction Chemicals
  • Masonry Saver / SaverSystems
  • Protecrete Densifier plus Repeller / Applied Concrete Technology, Inc.

Aquapel and Masonry Saver are sold through distributors and paint stores. Protecrete can be purchased direct from the manufacturer and from various stores. Check on the web sites of all these companies to see if there is a store near you, before you make a mistake and purchase an inferior product.

Great Books About Concrete

If you want to learn lots about how concrete should be installed, you must buy a copy of a neat paperback book published by the Portland Cement Association (www.cement.org). It is titled: Design and Control of Concrete Mixtures. This book is a little technical, but it has many very important facts and guidelines that will help you order and place concrete under all sorts of site and weather conditions.

The Portland Cement Association also has another book called The Homeowners Guide to Building With Concrete, Brick and Stone. This swell book contains some great photos, illustrations and numerous tables. It educates you about how to order and work with concrete. The book also shows you how to install brick and stone. It is a must have!

Manufacturers of Clear Coatings for Concrete

Many of the following manufacturers will not be familiar to you. Their products are not commonly sold at most local hardware stores or large home centers. To find quality products, you may have to hunt a little harder and drive just a little farther.

You are looking for the stores that professionals buy from. In many instances, you will find the products listed below at building supply stores where sand, cement and plaster are sold. Brick companies often sell these high quality clear coatings.

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

There are all sorts of products at home centers - many of them advertised nationally - that can hurt concrete in cold climates. These products contain silicones, acrylics or other film-forming chemicals. Films trap water at the surface of the concrete. This water is wicking up from the soil beneath exterior concrete slabs. Silanes and siloxane water repellents allow this water to pass through to the atmosphere.

Once again, beware of products that say they contain acrylics. You may be purchasing a film-forming sealant!

• BASF Building Systems
  • Enviroseal 20 Silane penetrant
    Enviroseal 40 Silane penetrant
    White Roc W Acrylic Sealant
• Saver Systems
  • MasonrySaver Silane/Siloxane
• ChemMasters
  • Anti-Spall 50 Penetrating blend
    Aquanil Plus 40 Silane moisture and water repellent

Fifteen Point Concrete Checklist

1. The Right Mix - The Portland Cement in concrete is the glue that holds everything together. The more cement that is included when it is mixed, the stronger the concrete will be. Exterior slabs, no matter if they are in Florida or Minnesota, need to be at least a 6 bag mix or a design strength of 4,000 pounds per square inch PSI. This mixture prevents freeze/thaw damage and simply allows concrete to perform superbly for 30 or more years.

A 7-bag mix is better. If you can afford to get 5,000 PSI concrete, do it.

2. Thickness - The minimum thickness of any exterior sidewalk or patio is 4 inches. Driveways should be a minimum of 5 inches. One extra inch of concrete will cost just a little more money, but it will return enormous benefits with respect to strength and durability.

3. Compaction of Base - The soil beneath slabs must be compacted. If slabs pass over trenches that contain uncompacted fill dirt, you can also have problems. All of these areas must be solid. Trenches that pass under driveways and sidewalks can be filled with gravel or some other self-compacting material instead of dirt.

4. Slope - If you live in a cold climate that can experience freezing temperatures, don't install flat slabs outdoors that will get wet! Make sure slabs are sloped so that water does not pond on the surface. Two inches of fall over 20 feet is usually not noticeable. You will think the slab is level.

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

5. Steel - Reinforcing steel is cheap. It is a must to have in all slabs. Use 1/2 inch steel bars if possible and make sure they are a minimum of 1.5 inches up from the bottom of a 4-inch slab. You want the steel bars in the lower third of the slab, but they need to have at least 1.5 inches of concrete under them.

6. No Added Water - Don't add water to the concrete once it arrives at the job site. Don't trowel in bleed water. Don't sprinkle water on the slab as you finish it. All of these things dilute the cement paste glue.

7. The Number of Control Joints - No single slab should be larger than 15 feet on a side. If your driveway is 12 feet wide, then space control joints every 12 feet to make symmetrical slabs.

8. Control Joint Depth - All control joint depths must be a minimum of 1/4 the thickness of the slab. This is non-negotiable.

9. Curing - After the concrete finishing is done, the curing process must start. Cover the slab with plastic sheets or apply a liquid curing compound. This process keeps water in the concrete so that the chemical reaction of hydration can continue. Without this water, the concrete will not reach its design strength.

10. Slump - Avoid ordering exterior slab concrete that is too wet. Wetter concrete that flows like water has a high slump number such as 5 or 6 inches. Four inch slump concrete is perfect, but it requires lots of manpower to place rapidly.

11. Type of Finish - Avoid slick steel trowel finishes for exterior surfaces. They are fine for basements and interior slabs. Garage surfaces should be a moderate steel trowel finish that is slightly abrasive. Drives, sidewalks and patios should have a light broom or wood trowel finish.

12. Sealers - They are not necessary to protect concrete from damage. They can be useful to prevent penetration of oil and other chemicals.

13. Expansion Joints - These are necessary when slabs touch fixed objects like foundations, street curbs, etc.

14. Weather Conditions - Don't pour concrete in extreme hot or cold weather. The ideal conditions are 55 degrees, overcast and high humidity.

15. Observe - If you are hiring out concrete work, try to inspect and watch the work crew. Make sure all of these points are followed or you will have problems. Put these specifications in your contract!

Control Joint Layouts for Driveways

The following two sketches give you an idea of how control joints should look for different residential driveways. The top drawing shows a double wide driveway approaching a two car garage. This is an easy one. The bottom drawing shows a two car garage that has a wide apron served by a single width driveway. Remember that the jointing tools of most concrete finishers will NOT cut the concrete deep enough. The joints need to be sawcut in the center of the joint at the end of the day or the next morning.

Concrete Scaling & Deicing Salts

I knew that when I wrote this column and bulletin set that I would upset many a concrete mason. It never fails. What disturbs me the most is not the criticism I receive, but the failure on the part of the contractors to admit their lack of understanding of the subject. Just this morning, I received an email from a concrete contractor. He told me that my column was inaccurate. I wrote back indicating that my facts were derived from the latest scientific data from both the Portland Cement Association and the American Concrete Institute. I then asked him from where he obtained his data. No response!  It makes you wonder what other facts about building and remodeling might be twisted in his head.

Writing this column has allowed me to really educate myself about the products and techniques used in the residential building industry. When I was still pounding a hammer each day, instead of this keyboard, I didn't have time to research facts. I was in the dark about quite a few things. You as a homeowner fight this battle everyday with contractors. Fortunately, the growth of the Internet has made it easy for you and contractors to obtain accurate information very quickly. I hope, for your sake, that you are taking advantage of this wonderful new media form.

Deicing Salt & Concrete

Let's set the record straight. Deicing salts will NOT harm concrete that is made correctly, placed correctly, and finished properly. Those three conditions cover much ground. For example, the concrete contractor at your house may do the job right. However, he may have been sold defective concrete. The likelihood of this is small. However, if you are planning on doing a large outdoor pour, I would give serious consideration to paying several hundred dollars for an insurance policy.

Concrete insurance? Yes. Simply find out if a local testing lab will come out and take several samples of the concrete as it flows from the truck. They will provide you with test reports that will tell you if the concrete was formulated to the right specifications. If it isn't, I'd say you would have a VERY strong argument with the concrete company to replace defective goods!  If you can't afford a test for a small pour then you must make sure you buy the concrete from a reputable company. The biggest company is not always the best.

Deicing Salt Comparison - Qualities

Many people don't realize that there are different deicing salts. The three common deicing salts or compounds (sodium chloride, calcium chloride, and magnesium chloride) do not chemically react with concrete, however, the salt brine solution can react and damage unprotected steel within concrete. The salts can also cause serious corrosion to both wrought iron and aluminum porch railings and posts. Deicing salts should be used sparingly if you have metal objects on or near your slabs or reinforcing steel within your concrete.

Get a 24-page guide right now that answers all your questions about Deicing Salts. Will it RUIN your concrete? Did you know that salt can SERIOUSLY harm you? What about your expensive landscaping? You can have all these answers and more in less than a minute. Buy it NOW.

Concrete Spalling Comparison Study

The National Research Council's Strategic Highway Research Program tested deicing salts to see how they would etch and destroy concrete. The tests were interesting. It appears that magnesium chloride did the least amount of damage. Calcium chloride caused 26 times more damage to the concrete than magnesium chloride. Regular rock salt, sodium chloride, caused an astonishing 63 times more damage. If the tests were accurate, it appears that it may be worth the extra money to purchase and use magnesium chloride.

Fertilizers as Deicers

If you want to really mess up your concrete drives, sidewalks and patios use fertilizers on them. I have listened to some garden show radio talk show people advocate this practice. It is a HUGE mistake! Many common garden and lawn fertilizers will chemically attack concrete. Do not apply these to your concrete in cold weather. In the spring and summer, be sure to rinse these materials from your concrete if you treat lawn areas nearby. Never use a fertilizer that contains ammonium nitrate or ammonium sulfate on concrete!

Water - Friend and Foe

Water is a key ingredient for concrete. When added to the cement, gravel and sand, it begins an irreversible chemical reaction. Crystals begin to grow. These crystals grab onto one another and the sand and gravel particles. Obviously, if you have more cement, you will have more crystals. Concrete which will be subjected to freezing temperatures must have a minimum of 564 pounds of cement for each cubic yard. Note that I said minimum. You can always add more if you want to really increase your chances of survival.

Guess what? You can have plenty of cement once the concrete leaves the plant but still run into a problem. Have you ever had iced tea? Have you ever added sugar to a full glass and get it just right? Then, after drinking half of the tea, a waiter comes and refills the glass. The color of the tea looks the same, but the taste is different. The sugar was diluted by the additional tea. You then add additional sugar to bring it back up to full strength.

If the cement in concrete is its sugar, then adding water to the mix once it has left the plant creates a problem. You dilute the amount of cement in the mix. The concrete becomes weak. The crystals are spaced farther apart.

Water is added to concrete at the job site for two primary reasons: it makes the concrete easier to place and it allows you to have fewer finishers on the jobsite when it comes time to apply the final finish.

Water sprinkled on the top layer of concrete will dilute the amount of cement in the upper layer. This is were it is needed the most to resist freeze/thaw cycles - the actual mechanism which causes spalling.

Slump

One last thing about water and concrete. You can purchase concrete with different amounts of water and cement. Let's say you want the concrete to flow readily at the jobsite. You would order it with a 5 or 6 inch slump. Slump means how many inches the concrete falls when a cone of it is left unsupported. The higher the slump, the more liquid the concrete.

So, if you want a liquid, high strength concrete, you must order it that way from the start. If they make a stiff (low slump number like a 3 or 4 inch) concrete to a given strength and then you add water at the jobsite, you reduce its strength! The added water at the jobsite dilutes the available cement. Low strength means the concrete is more susceptible to failure.

Prevention of Problems

If you want to solve concrete spalling problems, start with good concrete and finishing techniques. If you want to preserve concrete that has yet to deteriorate, apply some great silane/siloxane water repellents. If you have defective concrete, don't give up, it is possible to restore it. That subject was covered in great detail in Builder Bulletin 118.

Before your next concrete job, consider reading more about the topic. There are vast amounts of booklets, papers, etc. written about every aspect of concrete. Don't 'hope' for a good job from the contractor. Take the responsibility on your own shoulders and learn a little more about concrete and the way it is installed. Check out the following literature sources. You will not be disappointed!

Concrete Sealants

What happens if you do everything right and are still worried? You can purchase some excellent water repellents for concrete. Do not purchase film forming sealants. These products usually contain silicone or animal fats or waxes. Purchase a product that contains silanes, siloxanes or a blend of these two chemicals.

Concrete needs to be able to transmit water vapor from the soil into the air. Film forming sealants block this process. Silanes and siloxanes act like the fabric Gortex. Liquid water can't pass by the silanes/siloxanes, but vapor can.

Deicing Salt Information

Want great information on deicing salts? Simply call the Salt Institute. They will help you understand the facts about salt!

Concrete Literature Sources

You can go to any engineering college or the science/engineering department of any public library and be overwhelmed with information and books on concrete. However, if you want to go to the source, the core, of accurate, trusted information, then there are only two places in my opinion.

Get a 24-page guide right now that answers all your questions about Deicing Salts. Will it RUIN your concrete? Did you know that salt can SERIOUSLY harm you? What about your expensive landscaping? You can have all these answers and more in less than a minute. Buy it NOW.

You need to contact either the American Concrete Institute or the Portland Cement Association. Both of these organizations have scientists and huge funding behind them. You will also find great information on the statewide level. Most states have associations of the ready-mix suppliers. These organizations want concrete to be installed correctly just like you. If it fails, they are directly affected. Often these organizations have wonderful booklets, brochures, etc. You can find their addresses / phone numbers by calling your local ready mix supplier. If they don't know the address or who you are talking about, that is a bad sign! Maybe you should keep that fact in mind when you decide to buy concrete!

If you live in a major city, don't hesitate to contact a local engineering testing lab. Major cities have these companies. These are the places that take samples of concrete and test them for strength. Usually they can also point you in the direction of some great concrete literature.

• Portland Cement Association
  5420 Old Orchard Road
  Skokie, Illinois 60077-1083
  800-868-6733
  www.cement.org 
• American Concrete Institute
  38800 Country Club Drive
  Farmington Hills, Michigan 48331
  313-532-2600
  www.concrete.org

Pea Fill

My garage is attached to my house. I have a full basement. When I mean full, I mean full, as the foundation walls are nine feet four inches tall.

When you excavate the hole to place the foundation, you need to over-dig 30 inches beyond the outer face of the foundation. This gives the foundation people the necessary room to work on the concrete forms. But, when the pour is over and the forms are removed, you have a 30 inch trench to fill.

In my garage, I used a product called pea fill. This is a mixture of coarse sand and pea gravel. It is a processed material that you purchase from a sand or gravel pit.

Because of the small granular nature of the product, it is practically self compacting. I simply dumped this material along side my foundation in the garage. Along the nine foot deep wall (the other three walls were only three feet deep) I put in three foot deep layers of fill material.

After installing each three foot lift I would thoroughly saturate the pea fill with water. The water carried small pieces of sand down into the fill which in turn removed any small quantities of air. When the entire garage area was filled and brought to the level I desired, I watered all the fill for several hours.

Needless to say, my garage floor has not settled, tilted or cracked. I know, most of the other builders are unwilling to invest this time. Well, if you are getting ready to build, put it into the contract. So what if it costs $50 to $100 more. You will never regret it.

I highly recommend using this type of fill material in any outdoor location which will be covered with some type of paving material (sidewalks, concrete, blacktop, paving brick, etc.) .

Patios, Porch Stoops & Pins

OK, your builder dumped dirt along side your foundation. Now what do you do? You can still avoid a tilted slab with just 30 minutes of work, a hammer drill and some 16 inch long pieces of 5/8 inch reinforcing rod.

All you (or your builder) needs to do is pin your slab to your foundation. It is so easy to do!

All you need to do is chalk a line along the foundation indicating the top of your finished slab.The locations of the pins need to be marked on the foundation wall. These holes need to be spaced two feet apart and placed below the chalk line so that equal amounts of concrete will be above and below the pin (if the slab is five inches thick, you will drill the hole 2 1/2 inches below your chalk line). The hole diameter is the exact same size as the reinforcing rod pins you intend to use (#4 pins require a 1/2 inch hole, #5 pins require a 5/8 inch hole). Using a heavy (four pound) mini-sledge hammer, pound the pins into the holes. Believe me, if you have drilled the right sized holes it will be a snug fit. If you have the time and inclination, paint the pins with a rust inhibiting paint prior to pounding.

Now all you need to do is install additional reinforcing steel which is tied to the pins. The purpose of this steel is to make miniature beams. The concrete will be supported by the pins at the house and then hopefully span to soil or dirt which was never excavated. This way, when the fill dirt settles beneath the slab, the slab stays in place supported by the pins and steel. If you rely only on the pins for support, the slab will very likely crack at the end of the pins.

WARNING: Do NOT use pins if the slab is structural. That is, if the slab supports the weight of any other thing other than itself, the pins are not sufficient support. You will need to have a structural engineer tell you what to do.

If you have a shallow foundation, say four feet or less, there is a better way to support a slab that is in contact with the foundation. Before the dirt backfill is placed, simply install some four inch concrete blocks on top of the footer along side the foundation. This little ledge is a great support for the slab.

Slabjacking

The first challenge you face is getting an experienced slabjacker. An experienced slabjacker can usually determine why a slab settled. He/she can also tell you if the settling is complete. Remember, some settling continues for years!

Make sure that you ask what is going to be pumped under your slab. Avoid slabjackers who simply use topsoil or drilling mud. These materials just aren't the best products. Professional slabjackers use different mixtures and combinations of materials depending upon the job. BUT, these mixtures always contain Portland cement. The cement gives the grout strength after it gets hard and prevents erosion of the grout.

Ask the slabjackers if they will collect and save the dust from the drill holes. Request that this dust be mixed with the material used to plug the drill holes at the end of the lift. By doing this, there is a good chance that the color of the holes will closely match that of the slab. Failure to do this will result in a polka dot slab.

As usual, ask for copies of Worker's Compensation and liability insurance certificates when you receive your bid or quotation. I know, I know, it says right on their contract that they have this coverage. Well, do they? A professional will not hesitate to give you copies of these certificates.

Why not call the Better Business Bureau? Ask if there are any unresolved complaints. If so, consider finding another slabjacker. You may pay slightly more, but it will be well worth it in the long run.

Reinforcing Steel

Steel adds enormous strength to concrete. Concrete is strong in compression (squeezing) but weak in tension (pulling apart). You can pull concrete apart quite easily. For example, let's pour a slab on fill dirt. The fill settles and a hollow spot develops under the slab. Now let's drive my truck across the slab. The concrete stretches (pulls apart) to fill this hollow spot.

Put steel into the slab and it may take a tank to create the same effect. The reason is simple. The typical steel you buy at the supply house is almost always grade 40 steel. This means that it takes 40,000 pounds per square inch (PSI) of pulling pressure to tear the steel apart. Your slab, on the other hand, has only 1/10th the strength in tension as compression. Typical residential outdoor concrete is supposed to be 4,000 PSI in compression. This means it only takes 400 PSI to crack or pull it apart. Adding enough reinforcing steel can make the concrete 100 times stronger than without the steel!

I always had fantastic results by constructing a grid of steel in my slabs. By placing the steel bars two feet on center in both directions, I created a cage of steel. This steel must be surrounded by concrete. If you simply place it on the dirt, gravel or soil it will be worthless. The tension forces in a slab are concentrated in the lower third of the slab, so you should place the steel at the top of this boundary.

If you want to get fancy, you can purchase little supports that suspend the steel above your fill material. I usually used small broken pieces of brick or concrete block to support the steel. If your slab is larger than the length of the steel bars, be sure to overlap the steel at least two feet and tie the steel together with thin wire.

Lifting Concrete

The technology to lift concrete slabs has been around for many years. Highway slabs, airport runways, factory floors, etc. have been successfully raised for the past 40 years. However, until recently, the companies that did this work seemed to completely ignore the residential market. Now, in most cities, you can locate an individual who can magically raise a sunken or tilted concrete slab, floor or set of steps.

How is it Done?

The technology to lift concrete is centuries old. It is the same technology that is used to raise your car on a hydraulic lift at the car repair garage. Holes are drilled through the tilted concrete, usually two inches in diameter. A mixture of cement, sand, fly ash and water is then pumped into these holes under pressure.

This mixture has the consistency of a thick mortar. As it begins to flow beneath the slab, it exerts an equal pressure on every square inch of the concrete. Thus, if the pump produces just 50 to 100 pounds per square inch pressure (which isn't much) it can easily raise the slab.

You see, a concrete slab that is four inches thick only weighs 1/3 pound per square inch! Now do you see why it is so easy to raise a sunken or tilted slab?

Why did the Concrete Sink?

Good question!! There are all kinds of reasons. Usually, concrete slabs around your house tilt or sink because they were placed on fill dirt that was not compacted. This can happen just about anywhere.

For example, what about a sidewalk that is next to your foundation? How about a garage slab? What about a portion of a driveway or sidewalk that crosses a utility trench (one that contains a water, sewer, electric or phone line?) These situations almost always involve an excavation where dirt may have been simply dumped in after the work was complete.

Herein lies the problem. Buildings are built on dirt all the time. If done correctly, a house built on dirt will not settle or develop structural problems. The trick is to build the house on undisturbed dirt or soil that has good strength, or build it on compacted dirt that will support the structure.

Compaction

How many times have you dug a hole and tried to put the same dirt back in? Have you ever been able to do it without much work? I didn't think so. When you dig dirt, you fluff it. That is the technical term. In other words, you introduce much more air space around each clump or dirt particle than it had in the ground.

So, if you or your builder simply dumps dirt into a hole, trench or alongside a foundation, it will always have too much air in it.

The process of compacting dirt simply removes this excess air. Many years ago, shepherds noted that the paths that sheep walked on were very firm. They figured out that the shape of the sheep's hooves did an excellent job of compacting the soil on the path. That is why that big round roller that you see behind a bulldozer is called a sheep's foot roller!

Mother Nature will compact dirt. But, she often takes a while to do it. The sewer trench in my front yard continues to settle even after 10 years. Gravity and rainwater continue to force out the air I dumped into the trench.

This type of settlement not only causes concrete to tilt inwards towards the foundation, but it also causes a majority of basement leak problems. People generally don't recognize the the slow process of compaction as performed by Mother Nature.

Expensive Stuff

Concrete is made from basic, inexpensive raw materials. However, transportation and placement of these materials is costly and labor intensive. Because of its high cost and durability, people expect concrete to last for a long time. This is not an unreasonable expectation, as I have seen concrete 50 plus years old that is in very good shape.

But sometimes things go wrong. Your concrete drive, sidewalk or patio may experience a popout (depression caused by a piece of stone that explodes for numerous reasons). Those living in cold climates may experience spalling, a condition where the top surface of the concrete peels off. A corner of a concrete step may crack and fall off due to a handrail post expanding (rust and/or freezing expansion). In any event, a patch can be employed rather than replacing an entire segment of the concrete.

Challenging Task

I have seen numerous attempts at patching concrete. The majority of them have failed miserably. There are many reasons for patch failure. I'll try to cover some of the most persistent causes.

Concrete, in its original form (when first mixed) sticks together because of the cement. When the cement is mixed with water, a chemical reaction begins that is really pretty neat. Very small crystals begin to grow. These crystals interlock with one another and lock onto the pieces of clean sand and gravel. Also, when concrete is mixed, there is usually lots of extra water around to help keep the crystals growing. And grow they do, as the crystal growth slows down but can continue for years.

However, when patching, these two conditions are not always present. The area to be patched may be dirty and bone dry! If this is the case, there is a great chance that the patch will fail.

Water, water everywhere...

Remember when I spoke above of the growing crystals? The same thing happens, to a large degree, with many concrete patching compounds. They also need water for their crystals to grow.

Many people forget that concrete can and does absorb water. You can demonstrate this easily by getting on your hands and knees. Do this and place a drop of water on a piece of concrete. Observe what happens. The water, in almost all cases, readily soaks into the concrete surface.

When you place water based patching compounds on dry concrete, the concrete robs the water from the patching compound. No water, no crystals. No crystals, no bond. It is that simple.

Dirt also gets in the way as well. If dirt blocks the crystals from bonding to the concrete to be patched, all that happens is that the crystals bond to the dirt, not the old concrete.

Additives / Bonding Agents

To improve the chances of a patch sticking to old concrete, there are two categories of materials that you should consider. One category is additives and the other is bonding agents. They work towards the same goal, but they do it very differently.

Additives are chemicals or compounds such as rubber, vinyls, acrylics and different polymers that are sometimes added to portland cement mixtures. All they do is simply make the concrete mixture stickier. These compounds can be in a dry form premixed with a patching compound, or a wet milky liquid that you add to your patching compound. In either case, they work quite well when applied to a clean surface.

When using concrete patching compounds that contain additives, be sure to follow the instructions carefully. Some of these compounds must be applied to dry concrete surfaces, while others instruct you to wet the area to be patched. You must pay attention!

Bonding agents are glues that are applied to the old or damaged concrete surface that is going to receive the patch. These are almost always liquid compounds that you simply brush onto the clean, dust free area to be patched.

Once again, you must follow directions to the letter to achieve the best results. It is possible to use both compounds to maximize your chances of success. In other words, you can purchase a patching compound that contains additives - these are usually labeled as containing vinyl or acrylic,etc. - and use it in conjunction with a bonding agent. Always check the labeling to make sure the materials are compatible.

Epoxies

If you really want to go all out on your patching project, consider epoxies. These are no different than regular epoxy. You simply mix equal parts of a resin and a hardener together, often with a sand aggregate. You apply it and BINGO, super patch! The problem with some epoxies however, is coloration. You may not be really excited about the finished color. Some are white, beige, and very light grey. In contrast, regular Portland cement patching compounds dry to a medium grey.

The Old Stand By

Guess what? You can use just plain cement, sand and sometimes pea gravel to patch that hole. If done properly (50 percent cement - 50 percent sand and/or gravel), your patch will perform just fine.