Frequently asked questions about polished concrete
Frequently asked questions about polished concrete

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IS POLISHED CONCRETE EXPENSIVE?

Polished concrete is affordable to many and comparable in costs to other flooring options such a quality porcelain tiles. The costs do vary depending on the condition of the concrete to be worked on, the size of the concrete and the number of rooms included in the total area, how much diamond grinding is required and the geographical area that the works are due to take place.

As we do not lay concrete slabs you will need to also factor in the concrete cost and add to our quotation for a total job price. We will always quote each job separately and are confident you’ll not find a fairer quote elsewhere.

DOES POLISHED CONCRETE STAIN?

Polished concrete is not impervious to damage although concrete stains only usually occur when an accidental spill has been left to sit on the concrete surface for an extended period of time. With regular low-stress maintenance this can be avoided in most cases.

As standard, CARRcrete will always apply a stain-guard sealer on your concrete after it has been polished to make it relatively stain resistant. This sealer will repel spills and give you ‘reaction time’ with which to discover and clean the spill. If left for a number of hours, the sealer can be penetrated and stains can appear.

IS POLISHED CONCRETE EXPENSIVE?

Polished concrete is affordable to many and comparable in costs to other flooring options such a quality porcelain tiles. The costs do vary depending on the condition of the concrete to be worked on, the size of the concrete and the number of rooms included in the total area, how much diamond grinding is required and the geographical area that the works are due to take place.

As we do not lay concrete slabs you will need to also factor in the concrete cost and add to our quotation for a total job price. We will always quote each job separately and are confident you’ll not find a fairer quote elsewhere.

DOES POLISHED CONCRETE STAIN?

Polished concrete is not impervious to damage although concrete stains only usually occur when an accidental spill has been left to sit on the concrete surface for an extended period of time. With regular low-stress maintenance this can be avoided in most cases.

As standard, CARRcrete will always apply a stain-guard sealer on your concrete after it has been polished to make it relatively stain resistant. This sealer will repel spills and give you ‘reaction time’ with which to discover and clean the spill. If left for a number of hours, the sealer can be penetrated and stains can appear.

CAN YOU HAVE POLISHED CONCRETE OUTSIDE?

The quick answer is yes! We’ve worked on many outside patio spaces and have achieved great results. The difficulty with this lies in correctly protecting the concrete against our changeable weather, especially while the concrete is curing. Another consideration is that the concrete has to be dry when we work on it, so it can be risky to arrange this during the colder months. 

The concrete polishing process may be more complicated for an outside space but please speak to us and we’ll happily advise you accordingly.

CAN YOU HAVE UNDERFLOOR HEATING WITH POLISHED CONCRETE?

Absolutely, in fact 95% of the floors we work on do have underfloor heating installed. Concrete is incredibly thermogenic and works really well when used with water fed underfloor heating systems. We recommend that the concrete is laid to a depth of 100mm over the heating pipes as a minimum and we will give you special instructions regarding using your heating for the first time.

DOES POLISHED CONCRETE CRACK?

Truthfully, most concrete will crack but we can certainly put measures into place to control the extent of the cracking. Expansion joints (commonly called crack inducement joints) should be placed correctly in the concrete, particularly where a room changes direction and in doorways. Correct use of underfloor heating will help too.

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IS POLISHED CONCRETE SLIPPERY?

No, even when it has a glossy finish. Concrete actually provides a good level of foot traction and actually fares better than some other flooring choices such as lino or marble. Our PROseal and PROguard sealers offer a good level of additional slip resistance to concrete floors too although, as you would have to with any other flooring material, you should take care when wet.

CAN YOU POLISH ANY CONCRETE SLAB?

Is mine suitable? Not all concrete is polishable, particularly if it is excessively soft or damaged. Soft surfaces can occur when too much water is added to the concrete mixture. Screed surfaces are also not polishable directly. If you have any concerns regarding your floor then please contact us so that we can arrange an assessment of your floor and inform you truthfully of what can be achieved.

IS POLISHED CONCRETE WATERPROOF?

Concrete in its natural state is actually very porous and not waterproof, so we have to treat it in order to make it water repellant. We do this by treating it with concrete densifier which fills in the aeration holes within the slab. Polishing well to refine the surface and finally by adding a sealer in order to repel water and spills. 

Correctly honed concrete will always be more waterproof. We have sealers that incorporate hydrophobic and oliophobic properties which will essentially make concrete waterproof. It should be noted however that there is nothing on the market that can permanently make concrete waterproof.

HOW DO YOU KEEP POLISHED CONCRETE FLOORS SHINY?

A low stress maintenance routine should be introduced in order to keep polished floors shiny and clean. This essentially consists of dry mopping daily to remove dust and grit brought in from outside and a regular wet mop using a ph neutral cleaner, we recommend our PROcare product. 

For special occasions, you can also go over the surface with a high speed burnisher - these machines can be cheaply and easily hired. The heat and friction burnishing causes can restore the surface sheen on a well used floor.

DO POLISHED CONCRETE FLOORS SCRATCH EASILY?

There’s no doubt that concrete floors are very strong but the general perception that they are impervious to any damage often leaves them at risk of misuse. They are not scratched easily, but certainly can be scratched and the biggest culprit is from grit or pebbles caught in shoes. To avoid this we recommend the use of boundary mats to remove grit from shoes on entering a room. 

Concrete can also be scratched when heavy furniture is dragged across it etc. It has to be said however that with regular and considerate use polished concrete flooring is one of the most durable flooring systems around today.

IS POLISHING CONCRETE MESSY?

Surprisingly no! There is a lot of cleaning involved between each step we need to perform as polishers and we take a great deal of care not to make a mess while working. Dust will be created, especially if we’re grinding the concrete, however we have high powered vacuums on all of our grinders which almost totally eliminates airborne dust.

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HOW DO I MAINTAIN POLISHED CONCRETE?

Looking after polished concrete is low stress, but it does need to be regularly maintained in order to look it’s best for a long time. The dust mop is your friend! We recommend daily dry mopping to remove dust and debris that may be abrasive to the decorative concrete surface. 

Then a weekly wet mop using a ph neutral cleaner is usually sufficient, unless foot traffic is high. You shouldn’t need to top up the sealant on the floor except in cases of heavy use.

HOW SOON CAN I USE THE FLOOR AFTER IT’S BEEN POLISHED?

When we polish concrete, we finish by using a sealer which usually dries within 4 hours dependant on ambient temperature. Leaving overnight is preferable. On some occasions the floor may be dry when we leave site. Spills should be avoided for at least 48 hours when a solvent sealer has been used to allow the sealer to fully cure.

HOW LONG DOES POLISHED CONCRETE LAST?

Mechanically polished concrete can last for many years without any major maintenance if it is appropriately installed and maintained during that time.

HOW LONG DOES THE SHINE ON POLISHED CONCRETE LAST?

This depends on how much foot traffic there is on the floor, if shoes are worn on the concrete and how you maintain your floor. If you have your polished concrete floor polished to a high gloss shine, it will require more maintenance, but we’ll provide you with all the information you need to keep your polished concrete looking great.

HOW DUSTY IS CONCRETE POLISHING?

If the concrete we are working on needs a grind, there is no doubt that this is going to create dust. However, none of the dust that is created with grinding and polishing becomes airborne as we have a high powered vacuum attached to all of our machinery that will remove it. 

There will be heavy dust on the floor as we grind it and this is vacuumed separately in between every floor pass. You don’t have to worry about your premises being covered in a thick layer of dust!

ARE EXPANSION JOINTS NECESSARY?

We get asked this a lot and will always maintain that expansion joints/control joints are entirely necessary. Concrete will naturally want to crack in certain areas, particularly where the concrete changes direction or in doorways. By installing expansion joints you are doing all you can to prevent unsightly cracking across the surface of your floor where it will be seen. 

Control joints are usually sawn in 24-48 hours after the concrete is laid and should be cut down at least 30% of the entire concrete depth, preferably 50%.

IS POLISHED CONCRETE CHEMICAL RESISTANT?

As previously mentioned, concrete in it’s natural state is extremely porous and will need to be treated to reduce this porosity and become resistant to liquid (please see above question regarding stain resistance). Concrete doesn’t like anything highly acidic so we recommend you remove oil stains and acidic foods etc as soon as you discover them. 

We do have specialist sealers that will provide a certain amount of extra resistance against acidic and chemical spills and provide a reaction time in order for spills to be cleaned. Unfortunately, there is nothing on the market that will protect a concrete slab against chemical spills indefinitely.

CAN YOU POLISH AROUND OBSTACLES?

Although the majority of works we will perform on a concrete slab will require us to use large machinery, at CARRcrete we have many smaller pieces of machinery that we can use in certain situations. In particularly tight spaces or around anything that may be delicate, we can also work with a hand held machine for total control around obstacles, such as pillars or pipework. 

We do not recommend the grinding of concrete around large fixtures or fittings however.

IS POLISHED CONCRETE COLD?

Concrete doesn't have to be cold. Its thermal properties give it the ability to store and radiate heat and when underfloor heating has not been installed, it tends to take on the temperature of the space it’s in, so if the room is warm the floor will likely be warm. If glass bifold doors or something similar has been installed, you’ll find any concrete that is placed in direct sunlight can get very warm.

CAN YOU POLISH A CONCRETE COUNTERTOP?

You certainly can although these may be too small for us to take on for you. We will happily help you if you’re intending to do this and have the product’s you’ll need in our online store which we’ll be happy to point you in the direction of.

DO CARRCRETE POUR CONCRETE SLABS READY FOR POLISHING?

No I’m sorry. At the moment we do not offer this as a service however we will help you get the correct concrete to polish by providing you with a comprehensive specification. Simone will also be happy to speak to your chosen concrete contractor on your behalf and explain what is required and what may cause us problems down the line. 

We’re always on the end of the phone for advice if needed.

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CAN I CHOOSE THE COLOUR OF MY POLISHED CONCRETE?

This is an extremely popular question. If you’re working with a concrete slab, it is very difficult to control the colour unless you opt for a pre-pigmented slab. If being in control of the colour is very important to you, we would always recommend opting for our PROtop or Microfloor overlays where the colour can be controlled and you know what you’re going to get.

HOW LONG DOES POLISHING CONCRETE TAKE?

Floor polishing will be worked out on a job by job basis and is dependant on if grinding is required. For example a 50m2 slab to be ground and polished to our InfinityFloor Stone finish is likely to take 4-5 days. Polishing concrete is very labour intensive and we also have to factor in drying times for our densifiers and sealers.

CAN I HAVE STAINED CONCRETE?

Staining concrete after it’s laid is certainly something you can arrange however it’s not a service we offer. This is usually achieved by using muriatic acid (hydrochoric acid) or pigments suspended in an acetone solvent, which causes a chemical reaction within the slab. 

The grinding process exposes differing levels of sand and cement and aggregate across the concrete, therefore the acid produces uncertain and patchy results which we’re not keen on.

WHAT ARE THE BENEFITS OF POLISHED CONCRETE OVER OTHER FLOORING TYPES?

Polished concrete is incredibly durable, versatile and low maintenance. It works incredibly well with underfloor heating and what we like most about it - no two floors are the same.

WHAT IS THE MINIMUM DEPTH CONCRETE SHOULD BE POURED IF I WANT IT POLISHED?

We recommend installing concrete to a minimum depth of 100mm, especially if it’s being installed over underfloor heating. Laying your slab to this depth will decrease the risk of the slab cracking excessively.

WHAT AREAS OF THE COUNTRY DO CARRCRETE COVER?

The team here at CARRcrete are happy to travel nationwide and we have even taken on international work. All project locations will be considered, get in touch!

WHAT’S THE DIFFERENCE BETWEEN POLISHED CONCRETE AND EPOXY?

An epoxy floor has a uniform, almost plastic looking floor surface that can be scratched easily. We do not use any floor coatings at CARRcrete, especially coatings and epoxy coating used as a sealer as we believe it detracts from the natural appearance and organic nature of concrete.

IS POLISHED CONCRETE GOOD FOR THE ENVIRONMENT?

Concrete is unparalleled as an environmentally friendly flooring material. Made from readily abundant natural materials, it can help to improve air quality, reduce waste, and even cut down on your heating bills. Few, if any, raw materials are consumed. The process of polishing concrete floors has a small footprint with regard to raw material consumption. 

The only products that are applied to existing concrete floor slabs are water-based hardeners and stain-resistant treatments.

More specifically to CARRcrete, we use recycled media in our PROtop and Microfloor overlays and commit to using environmentally friendly products as our product range grows.