15 Dec 2010
Concrete floors.
Image by tracy out west via Flickr

What is all the talk about “Polished Concrete Floors?” Polishing and grinding concrete floors has been a topic of discussion over the past few years, and I’ve been asked so many times what it’s all about, that I decided to write this article. Hard surface floors have been around since the time of the Roman Empire. It took an enormous amount of labor, and a lot of ingenuity to split large stones, and hone them down to make slabs suitable for flooring in buildings. To get more specific than that is mind boggling, kind of like, “How did they build the Pyramids in Egypt? ” My answer is, “I sort of know how they did it, but I’m glad I didn’t have to do the work”.

Fast forward a little, and we come to more recent times when people discovered that you could mix Portland (a clay substance) with sand, stone and water, to make the first concrete. The mixtures have been tweaked over the years, but the process has virtually remained the same. Contractors have used different curing agents, have implemented the use of steel bar to hopefully prevent concrete from cracking, and have implemented different types of moisture barriers to improve on the finished product.

Building owners have wanted different types of flooring over the concrete to give a building a warmer, and cleaner feel. In industrial facilities they have used tile, rolled linoleum, floor paint, or epoxy to give a building a more desirable appearance, and make it easier to clean than bare concrete. That works for a while, but everyone of those products eventually wears out and requires replacement. That brings us up to the present time.

Since early in the twentieth century, scientist experimented with different compositions to come up with a flooring products that would last for a long period of time. Some tile products were made up of an asphalt base. Some were made more durable by adding asbestos to the mixture. Don’t get me wrong, it was a good product, and after 40 years in the business, I’ve seen some asbestos tile that goes back at least 60 years, and is still in nice condition. The problem is that asbestos is a Carcinogen, and once the tile is broken, or disturbed, you can very easily be exposing yourself to cancer causing agents, in the air. Guess who arrives on the seen when something like that is reported? You got it! The Guys with White Hats Riding on White Horses. Now it’s time for the asbestos abatement crews. Can you say, BIG BUCKS?

Abatement is a tedious, and time consuming process, but it has to be done, before you can begin the process of restoring the concrete floor underneath. You cannot do it yourself! Asbestos Abatement requires countless hours of training, certification, annual re-certification, special equipment, and people who are crazy enough to want to do it. Just kidding! Luckily, there are people who enjoy that type of work, and take pride in providing an excellent finished product.

I, much prefer coming in after the cleanup has been completed. Concrete grinding equipment has been in the development stage for over 70 years. Changes with some companies especially over the last 5-10 years have been dramatic. Why? Because, the government has determined that there are enough floors out there, that are wearing out or damaged, that they need to step in with some requirements for removal, since many of these floors are in public buildings. So what are my options as a facilities or building manager? First, you need to go on-line, and find a very reputable asbestos abatement firm, and get an estimate. Second, you need to find reputable Concrete Restoration firm to give you the options at their disposal. Next, you are going to have to put together a budget for the completion of the work, so that you, your board of directors, or your school board is not shocked by the cost of the completed project. And finally, you are going to have to schedule the work.

Due to the cost of the abatement, and the fact that they will need to tent off areas while the abatement is going on, there will be some need for some logistical planning. What you don’t want to do is put it off, hoping the problem will cure itself, or go away. That’s not going to happen. It doesn’t happen that often, but I have seen instances where the inspectors come in and demand that the problem is corrected before the building can be used again. That’s ugly!

Do you know the definition of the word, “Problem”? It ‘s a situation that you don’t deal with. There are currently thousands of floors in public and private schools, colleges, universities, court houses, and other public buildings who have been fore warned that they need to get rid of asbestos floors.

Over the past five to ten years, they have continually been given an extension, or given a “pass”, due to the fact that “They don’t have money in their BUDGET”. Actually, the first time I heard that was 1981, and the budget has gotten tighter every year. This has lead to the advent of equipment and grinding pads for “The Do It Yourself”, types. Guess what? They don’t work.

If you want your custodian, to spend hundreds of hours with a 250 RPM swing buffer, grinding grooves in your beautiful eighty year old Terrazzo, or Marble floor, by all means, GO FOR IT.

THEN WHO SHOULD I TALK TO?

You can hire a very reputable Concrete Grinding and Polishing professional, who only does floors, for a lot less money than you would expect. They can grind, polish, seal, dye, or apply one of hundreds of products to your floor for the same or less money than re-applying tile which doesn’t have the same resiliency, and longevity as the previous asbestos tile products.

You can install carpet which typically has no more than 5-7 year life expectancy. Or you can go with a dyed floor that will outlast all of us. The options are endless, but you need to find a contractor that you can trust, and do a little homework before making your decision. Some may suggest products that you would call floor paint or epoxy. What are the advantages or disadvantages of that type of product? There’s probably nothing wrong with that, but you need a few facts before making your decision.

Floor paint that you would typically buy in a home improvement or hardware store is fairly easy to use, but generally will not hold up to much traffic, either tires or foot traffic. And in order to get the best results you still need to do most of the prep that would be necessary for the other products. Epoxy is more durable once it is cured, but can be damaged if exposed to some abuse before it is completely cured. (Two days for foot traffic) and (Up to thirty days for wheel traffic). If you can’t live with that, then you need to consider other options.

WARNING!

Epoxy is not easily repairable, and carries “NO ” warranty, if strict recommendation for it’s care are not observed. Don’t expect the contractor to come back a week after your beautiful floor was redone to fix tire marks in your shop. It’s not possible! If you want a floor that is less sensitive, then you should probably consider application of a penetrating dye, followed by sealer to give you an attractive floor finish which is going to be less susceptible to marring and scratching.

Okay, so now the questions. Are these types of floor finishes slippery? The best way to explain that is to explain the grinding and polishing process.

When concrete is poured you are bound to have some inconsistencies. Why? Have you ever poured concrete, or watched it being poured? No matter how good you are, or how good your equipment is, getting a large slab of concrete completely level, is next to impossible. The loads of concrete from the ready mix company can be inconsistent from one load to the next. Most concrete is poured in the summer when heat and wind can affect the rate of time for the concrete to dry. If it’s poured in the fall or winter drying and curing agents are added to the mix which can also lead to problems later on. Bottom line is, the finished floor can have plenty of imperfections in it for you to deal with.

The newest equipment which is generally used by a concrete restoration company is meant to apply enough pressure to the diamond cups or “stones” under the machine that given enough time, will do a very good job, of leveling your floor. The grinding equipment generally weighs between 1,200 and 2,500 pounds which is a whole lot more head pressure than your swing buffer. A typical grinding machine is going to have no less than a dozen stone which turn in a synchronized motion to pulverize the top 1/16″ to 1/8″ of concrete, exposing the softer sub-strata below. Why is it softer? Because as you will recall, I talked about the curing agents which is applied at the time the concrete was poured. That product is meant to harden the top surface, and needs to be taken off before you can really get into “Mechanically Changing” the floor. So you’ve got the skin off of the floor. What’s next?

Next, you go to a little finer set of grinding stone to continue the grinding/leveling process. You go in straight lines in a defined area to make sure each section of floor is ground evenly. All floors will require overlapping with the machine. Some will require changing direction with the machine to level the floor properly. All floors will require edging up against walls and in doorways to grind and level the floor adequately. All of this requires floor technicians with a pretty significant amount of experience and training to do the job the right way.

Doesn’t this create a lot of dust? Good question. Yes it does, but depending on the quality of the grinding equipment which includes some pretty high efficiency and expensive vacuums with double “Hepa” filters, that are attached to the grinder, 90-95% of the dust is sucked right into the vacuum to be disposed of. What else?

What about noise? The grinders are generally not that noisy. The vacuums are, but can generally be operated so that they are of minimal impact to the public. Sometimes the work has to be done in the middle of the night. Sometimes areas need to be tented off to protect the public, or protect adjacent areas. That is all left up to the companies estimator to figure out all of those logistical issues.

Bottom line is: If it has to be done, the right company will be able to accommodate all of these issues. How much area can be done in a typical eight hour shift? Generally, about 1,000 sq. ft. with each machine and a crew of 3 people. That includes edging, grinding with two different grits of stones, and at least two, if not three passes with diamond impregnated polishing disc’s. As you can see, I still haven’t answered the question about whether the floor is going to be slick. Don’t rush me, I’m getting to it.

The amount of polishing necessary is going to be determined by the customer. Since we talked about what concrete is actually made of a long time back, you will remember that it is mostly clay, and sand. Oh yeah! And rock. And depending where you are at, and the age of the floor determines how much, and what type and size of rock is in your concrete floor. It may be pretty ordinary, or it may be absolutely beautiful stone. On some jobs you are going to feel like a jeweler polishing stones with impeccable beauty even though it may be nothing but river rock that has been buried for years. Many ordinary concrete floors when ground and polished with good quality equipment will look more like Terrazzo than concrete. Terrazzo is a concrete mix that is poured like concrete, but has a specific mixture of small stones or marble chips in the concrete mix which is meant to have a lot more natural beauty than concrete. But trust me, you may be amazed at what concrete can looked like with the proper grinding and polishing.

After the grinding and polishing is complete, you have brought out the natural beauty of the stone. It may not look like it yet, but it will, once the penetrating sealer is applied. This product is meant to penetrate the soft “sub-strata” of your floor. Once it is dry to the touch, your floor is ready for high speed burnishing. I like Propane powered burnishers which run at 2,500 RPM. With a diamond impregnated burnishing pad the machine will create enough heat on the floor to bring out the maximum luster of the floor whether your original concrete mix was a very sandy mix, or has a lot of brilliant stones in it. One way or the other, you are going to have a highly polished floor. Your floor is going to have the appearance of a Terrazzo or tiled floor floor with numerous coats of floor finish on it.

You’ll notice I don’t call it wax, as many people do. That’s because it isn’t. Wax hasn’t been used on floors for 25-30 years. When I first started doing floors in the 60′s, we actually used natural wax on floors. Very labor intensive. Next came what most people call wax. It is actually a plastic product or “Thermoplastic”. That means it shines up nicely when exposed to heat from a burnisher.

Note: We now have the ability to wet grind and polish Terrazzo floors and apply a similar sealer eliminating the need to EVER strip and wax a terrazzo floor again. This is totally revolutionary, and should be done to every Terrazzo floor, in that it is much more “Green Friendly” than using caustic stripper and dumping the spent product into your sewer system several times per year. That’s why these products were supposed to have been taken off the market 10-15 years ago.

Synthetic plastics are actually applied to the top surface of the floor. From here on out I will refer to them in a category of “Topical Coatings”. Here’s when we get to the good part.

Topical coatings are what can actually make the floor slick, especially when wet. The process we just talked about is penetrating, not topical, which in essence makes it less slippery.

And now the cool part! Have you ever seen guys carrying big sheets of “Plate Glass”, with suction cups? How do they do that? I’m glad you asked. It’s called “Tension Strength”. The surface is so smooth that the cups retain contact with the glass. That’s what your floor is going to be like once it is properly ground, and polished.

If there is no topical product on the floor, the floor is less slippery than with paint or epoxy. And if there is nothing on the surface of the floor it is virtually scratch and chip resistant. Is it chemical resistant? Some are better than others, but it’s only common sense that if you spill something that might damage the finish, then clean it up as soon as possible to minimize the chances of damage.

How long does a product like this last? It depends on the product, but many manufacturers offer at least a five year warranty against any product failure. Theoretically the product can last much longer with proper care and a little maintenance (i.e. keeping it clean).

I don’t mean to give Epoxy a bad rap. There are many good manufacturers. They have to be mixed and applied quickly by an experienced technician to prevent product failure. And, there are some that are more slip resistant than others. So you are going to have to trust your contractor to advise you on the right product, and look at some comparisons on the products on the internet.

Article Source: http://EzineArticles.com/?expert=Dave_Meseck

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