McmullenLarry723
Polished concrete is powerful, durable and low maintenance while having that earthy texture of stone with a polish comparable to granite. Here is how it is done.
It's just like traditional polished terrazzo which is very flat and poured as a special mix to create the finish more successful. Polished concrete floors may also look almost bumpy and have little or no aggregate showing. Flatness and polishing are not necessarily the same thing that is a good point to clean up before acknowledging your project.
It costs additional time and diamond wear to chop floors having a concrete grinder until they're flat. They are able to be either ground flat to completely expose the aggregate like terrazzo, or even the aggregate can be partially exposed, or even the concrete grinding can expose no more than the fine sands at the surface. It often takes skill and experience to manage the process of polished concrete floors and the excellence of the concreter's original laying work is also a contributing factor in the caliber of the conclusion. Where the aggregate is a feature special materials could be put into the wet concrete mix such as coloured pebbles, metals and glass to boost the ultimate appearance.
Many people are unaware there are ten to fifteen steps for polished concrete floors that takes a long time to complete and can be quite expensive.
Typically it takes many grinding passes to finish a very polished floor however, there are also ways as explained later. The overall rule would be to double the diamond grit size underneath the concrete grinder for every pass so a contractor might start with very coarse, 16 or 32 grit size diamonds, then use 60 grit diamonds followed by 120, then start again with a 50 grit diamond resin pad rather than a metal segment. While using resin pads the steps might be 100, then 200, 400, 800, 1500 and finally 3000 grit. That might be ten separate grinding passes which does not count the 2 other essential steps.
Two more valuable steps:
1. Hardening the top
Polished concrete floors usually have the top hardened having a chemical prior to the second, third or fourth grinding pass. Caffeine soaks into the floor to a couple millimeters (up to half one inch) and results in a chemical reaction to occur that makes the floor harder and simpler to shine to a high finish. These floors are extremely resilient and strong without having a surface coating.
2. Filling holes
Following the first concrete grinder pass removes the very best layer of concrete paste it'll expose countless tiny air holes. If these are not filled before the hardening process then the final polished concrete floor can have these unsightly imperfections. The holes are often full of an acrylic tile adhesive kind of product combined with either the grinding dust or cement powder which is hand scraped over the floor using a trowel. The most well-liked way to fill the holes would be to spray the acrylic adhesive ahead of the grinder so the diamonds mix it in to the holes using the grinding dust around the third or fourth pass around 120 grit. This process is quicker and the dust matches the colour from the floor to cover the holes better than when utilizing cement powder.
Very flat or slightly bumpy polished?
Some floor grinder machines are made to produce a very flat floor by cutting off our prime spots while some others are designed to stick to the contours from the floor more. When the surface will be polished without necessarily exposing the aggregate then just the finer resin pads have to be utilized on a concrete grinder that enables for movement from the pads to allow them to stick to the contours of the surface. This will result in a polished floor without showing the pattern and texture of the exposed aggregates within the concrete which is faster and less expensive. Hardening can nonetheless be a benefit to assist the sturdiness from the surface and to create a final gloss.
Issues with exposed aggregate
Sometimes the conclusion of exposed aggregate could be uneven if the mix of concrete was poured unevenly or finished off poorly. Boot marks or kneeling board marks can be displayed suddenly simply because they have pushed the aggregate down further which might require grinding down another 2 or 3 millimeters (quarter of an inch) that will are more expensive than was quoted. Grinding this far may not be what the customer wanted either therefore it could be a risk.
Single head or multiple head machines
Original terrazzo grinding was done with single head floor grinders before the manufacture of three-head planetary machines. Planetary implies that each head turns one direction while the turntable that houses the heads turns independently either in the same direction or even the opposite direction. Some grinders can differ the direction of both turntable and also the heads plus some can differ the speed of each. There are also multiple head planetary machines with four or even more heads.
The planetary heads can follow the contours better than single or twin head grinders and are faster to make use of with less effort due to eliminating the requirement to physically move the grinder from side to side or perhaps in a circular motion. Single head terrazzo grinders ought to be moved in a circular motion to avoid grinding lips or shoulders.
Edging
As with wood floors the perimeters must be finished separately towards the main floor area because the large machines may bump and damage the walls if they are used too close. For the first grinding passes a nine inch angle grinder can be used having a diamond wheel that come with a dust extraction shroud suited to remove the dust. The sit-down-to-use edge grinders tend to be more controllable than stand up grinders while kneel-to-use grinders have good control, but they are exhausting.
Following the first couple of or three cuts another dust extraction shroud having a corner feature is used with a seven inch polisher or perhaps a five inch, multi speed grinder to shine with resin pads and obtain tight into the corners.
Simple polished concrete floors "look"
The amount of processes for polishing concrete could be reduced by as much as 60% and still acquire a similar appearance by grinding and then coating having a clear sealer. The initial step would be to grind with 30/40 grit diamonds to reveal the aggregate, then fill all of the small air holes as described above (in Ten to fifteen steps....) before a second grind with 60/80 grit or 80/100 grit diamonds.
This will produce a smooth enough surface to coat with a sealer. Polyurethanes are extremely hard sealers having a glossy and can be purchased as UV stable to stop yellowing (usually double the price of non UV stable urethanes), clear epoxy sealers are not as smooth and will chalk and deteriorate if subjected to sunlight and acrylic sealers have a much shorter lifespan because of their poor resistance to wear. Two coats are necessary to provide a glossy level.
Different ways to attain "polished concrete"
The very first is to chop the floor with coarse diamonds until all the high spots have been removed to make a flat floor and then use all of the 12 to fifteen steps to eventually polish it or as it is sometimes called, hone it. This is the true polishing system.
A variation of the aforementioned would be to cut perhaps half of the peak of the higher peaks by beginning with a medium coarse diamond grit and proceed through to polishing using a machine that can ride up and over small rises.
Another alternative way of manufacturing a honed surface is to start with relatively fine diamonds and just polish to top of the surface after hardening without removing a lot of the very best cement paste. It is simpler to perform this when the floor continues to be laid flat and smooth.
Lastly, a "polished look" can be acquired by grinding with coarse diamonds and then fine diamonds before coating over and done with a clear sealer.
Only truly polished floors will retain their gloss with little maintenance because all coatings scratch with wear and lose their high shine. Special buffing pads on the standard floor polisher that contain very fine diamonds may be used to maintain cleanliness and also the high gloss amounts of true polished concrete. Janitors can be provided with these and the floors in great condition without special therapy.
Some hire companies provide the grinding equipment for do-it-yourself concrete polishing and have all of the pads with the objective. This may not be so economical though since the pads may be only half worn when you finish depending on the area involved.
