利用者:SimpkinsSerna868
Polished concrete is powerful, durable and low maintenance with that earthy texture of stone having a polish comparable to granite. Here is how it is done.
It is similar to traditional polished terrazzo which is very flat and poured like a special mix to make the finish more successful. Polished concrete floors may also look almost bumpy and have little or no aggregate showing. Flatness and polishing aren't necessarily the same thing which is a good point to clear up before agreeing to your project.
It costs extra time and diamond wear to chop floors with a concrete grinder until they are flat. They are able to either be ground flat to completely expose the aggregate like terrazzo, or the aggregate could be partially exposed, or the concrete grinding can expose no more than the fine sands at the surface. It often takes skill and experience to manage the entire process of polished concrete floors and also the excellence of the concreter's original laying work is also a contributing factor in the quality of the finish. In which the aggregate is really a feature special materials can be added to the wet concrete mix such as coloured pebbles, metals and glass to enhance the final appearance.
Many people are unaware that there are 10 to 15 steps for polished concrete floors that takes a long time to accomplish and could be very costly.
Typically it takes many grinding passes to finish a very polished floor although there are other ways as explained later. The general rule would be to double the amount diamond grit size underneath the concrete grinder for each pass so a contractor might begin with very coarse, 16 or 32 grit size diamonds, then use 60 grit diamonds then 120, then start again having a 50 grit diamond resin pad instead of a metal segment. Using the resin pads the steps might be 100, then 200, 400, 800, 1500 and finally 3000 grit. That might be ten separate grinding passes which doesn't count the 2 other essential steps.
Two more valuable steps:
1. Hardening the top
Polished concrete floors will often have the surface hardened having a chemical prior to the second, third or fourth grinding pass. The chemical soaks in to the floor to a couple millimeters (almost half an inch) and results in a chemical response to occur which makes the ground harder and easier to shine to a high finish. These floors are very resilient and strong without having a surface coating.
2. Filling holes
After the first concrete grinder pass removes the top layer of concrete paste it'll expose countless tiny air holes. If these are not filled prior to the hardening process then your final polished concrete floor can have these unsightly imperfections. The holes are usually full of an acrylic tile adhesive type of product mixed with either the grinding dust or cement powder that is hand scraped over the floor utilizing a trowel. The most well-liked way to fill the holes would be to spray the acrylic adhesive in front of the grinder so that the diamonds mix it into the holes using the grinding dust around the third or fourth pass around 120 grit. This process is quicker and also the dust matches the color from the floor to cover the holes better than when utilizing cement powder.
Very flat or slightly bumpy polished?
Some floor grinder machines are designed to produce a very flat floor by reducing our prime spots although some other medication is designed to follow the contours from the floor more. When the surface is to be polished without necessarily exposing the aggregate then just the finer resin pads have to be utilized on a concrete grinder that allows for movement from the pads so they can follow the contours from the surface. This can result in a polished floor without showing the pattern and texture of the exposed aggregates within the concrete that is faster and less expensive. Hardening can still be an advantage to help the durability of the surface and also to produce a final gloss.
Issues with exposed aggregate
Sometimes the finish 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) which will are more expensive than was quoted. Grinding this far might not be what the customer wanted either so it can be a risk.
Single head or multiple head machines
Original terrazzo grinding ended with single head floor grinders until the production of three-head planetary machines. Planetary implies that each head turns one direction as the turntable that houses the heads turns independently either in the same direction or the other direction. Some grinders can vary the direction of both turntable and the heads plus some can vary the rate of each. There's also multiple head planetary machines with four or more heads.
The planetary heads can stick to the contours much better than single or twin head grinders and therefore are faster to use with less effort due to eliminating the requirement to physically move the grinder laterally or in a circular motion. Single head terrazzo grinders should be moved inside a circular motion to prevent grinding lips or shoulders.
Edging
As with wood flooring the edges 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 that first grinding passes a nine inch angle grinder can be used having a diamond wheel attached with a dust extraction shroud fitted to take away the dust. The sit-down-to-use edge grinders are more controllable than fully stand up grinders while kneel-to-use grinders have good control, but are exhausting.
Following the first couple of or three cuts another dust extraction shroud having a corner feature can be used having a seven inch polisher or perhaps a five inch, multi speed grinder to polish with resin pads and get tight in to the corners.
Simple polished concrete floors "look"
The number of processes for polishing concrete can be reduced by up to 60% but still achieve a similar appearance by grinding and then coating having a clear sealer. The first step is 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 can produce a smooth enough surface to coat having a sealer. Polyurethanes are very hard sealers having a high gloss and could be purchased as UV stable to prevent yellowing (usually double the cost of non UV stable urethanes), clear epoxy sealers aren't as smooth and can chalk and deteriorate if exposed to sunlight and acrylic sealers have a much shorter lifespan because of their poor potential to deal with wear. Two coats are necessary use a glossy level.
Different ways to attain "polished concrete"
The first is to cut the floor with coarse diamonds until all of the high spots have been removed to produce a flat floor after which use all of the 12 to fifteen steps to eventually polish it or because it is sometimes called, hone it. This is the true polishing system.
An alternative of the aforementioned is to cut perhaps 1 / 2 of the height from the higher peaks by starting with a medium coarse diamond grit and proceed through to polishing using a machine that may ride up and over small rises.
A third alternative route of manufacturing a honed surface would be to start with relatively fine diamonds and just polish to top of the surface after hardening without removing a lot of the top cement paste. It's simpler to perform this once the floor continues to be laid flat and smooth.
Lastly, a "polished look" can be acquired by grinding with coarse diamonds after which fine diamonds before coating over with a definite 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 a standard floor polisher which contain very fine diamonds can be used to maintain cleanliness and the high gloss amounts of true polished concrete. Janitors could be provided with these and the floors in great condition without special treatment.
Some hire companies provide the grinding equipment for do-it-yourself concrete polishing and have all of the pads for the purpose. This may not be so economical though because the pads might be only half worn whenever you finish depending on the area involved.