Frequently Asked Questions

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FAQ’s

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What types of polished concrete do you offer?
OzGrind offers both a mechanically polished concrete such as the hiperfloor method and we offer a coating method commonly known as a grind and seal. We also do honed concrete, and epoxy flooring.
What is the difference between mechanically polished concrete (MPC) and a grind and seal (G&S)?

Mechanically polished concrete is for indoors only – it is the true form of polished concrete as it is the concrete itself that is polished and buffed until it shines – there is no topical coating and therefore there is nothing to wear away over time, and it will last you many years. With floors that are mechanically polished like a hiperfloor the concrete is hardened and densified to up to 10 times its natural strength so it is much less likely to crack. The concrete is also grouted which is a process that fills in the small pin holes and cracks on the surface which leaves the top smooth and very refined – so if you run your finger across the floor it looks and feels like glass. Then the floor undergoes a series of polishes using resins which make the floor smooth, shiny and glossy – you can finish the procedure after just a few polishes so that you end up with a matte finish – or you can continue to polish up to a very high grit for the semi or high gloss finish. The MPC is a very luxurious floor and is very highly recommended by the team at OzGrind.
A Grind and Seal however can be used for indoor or outdoor – and is a cheaper alternative to the authentic polished concrete and very popular in cafes and restaurants as well as outdoor areas, garages, driveways and homes. This procedure involves grinding the concrete to prepare it for a clear coating of a sealer like a polyurethane or epoxy. The clear coating will protect your concrete and if desired we can use a special grit in the top layer in order to make floors non-slip (ideal for around pools, and any wet areas). The final product still looks similar to the mechanically polished concrete, however it is the sealer that gives the floor an artificial shine – and so like any topical coating, over time this will start to wear and eventually need to be sanded back and re-applied. Sealers will generally last 2-7 years depending on traffic and they are available in a matte, semi-gloss or a high gloss finish.

Grind & Seal

grind-and-seal-1 grind-and-seal-2

Mechanically Polished

mechanically-2 mechanically-1

What is the difference between mechanically polished concrete and honed concrete?

Honed Concrete is a finish which is not quite as refined as Mechanically Polished Concrete, but it is an alternative to Mechanically Polished Concrete for outdoor areas. Honed concrete is usually grinded to a 60 or 120 grit so that it is slip resistant and it has a penetrating sealer applied to protect the concrete – this can be done in an invisible sealer (no change to colour of the concrete) or a colour enhanced sealer (which will enhance/darken the concrete). Mechanically Polished Concrete on the other hand is a more involved process that involves densifying and hardening the concrete and then applying resins to polish it up until it shines. This process however can be stopped at a matte finish, or you can continue to polish up to a semi or high gloss. Please see example images below of the two finishes.

Honed

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Mechanically Polished

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Can you stain the concrete if you want a different colour?

Yes, but keep in mind that not all concrete absorbs at the same rate, so colours may not be uniform. See colour examples below of colours available and some examples of how it looks on a concrete floor.

concrete-dye-colorcolour-eg2 colour-eg1

Can you colour match an existing slab if a new one is poured next to it?
It is possible for us to dye the concrete in both slabs the same colour – unfortunately the colour uptake by these slabs will not be exactly the same, however this will be the best way to get them looking similar.
Do I have a choice of coloured concrete and aggregate?

If you are lucky enough to be building a new house or extending, you will most likely be pouring a new slab from scratch. In this case you will be able to choose from the vast range of concrete mixes that are available in your area. OzGrind prefers to use Hanson concrete mixes – the options available for Queensland are shown below. If you are renovating however and using the existing slab – you are more bound by whatever colour cement and aggregate is in your floor – the only real option if you want to change the colour is to use a concrete dye – however most customers are happy with the polished concrete look no matter what colour the cement and stones are.

colours-choice

What do you recommend for cleaning a polished concrete floor?

Polished concrete is so easy to maintain! – All that is really required is a daily dust – The best results can be obtained by using a dry Micro-Fibre Dust Mop. It is important to ensure spills of any kind are wiped up immediately and not left to soak into the floor.
For a weekly clean on a polished concrete floor, use water only or you can add a cleaner made for polished concrete or any pH neutral all-purpose cleaner.

Will polished concrete fade or discolour over time?

One of the biggest advantages of Honed concrete and Mechanically Polished Concrete is that it will not fade and with proper care will not discolour, however grind and seals or any sealers that don’t have a UV stable coating on the surface will, over time, discolour and may lift, crack or peel.

Can you do this after hours?
Work can be performed on weekends and after hours, however surcharges apply.
How much dust can I expect?
OzGrind use only the best available equipment from Husqvarna to eliminate dust. The process is virtually dust free. There is actually no airborne dust due to the use of our large Hepa filter vacuum systems which work to contain all the dust produced by the process. There will be some residual dust left after we have completed our job – but you would only expect to see an amount similar to if you had not dusted your home for 4-6 weeks.
How long before I can walk on polished concrete?
One of the advantages of Mechanically Polished Concrete is that once the process is complete, you can walk on the floor straight away – there is no time wasted waiting for a coating to dry. However you should avoid water being left on the floor or the floor being cleaned with water for 24-72 hours. For an epoxy coating or a grind and seal however we recommend no foot traffic for a period of 24 hours and no heavy traffic (vehicles etc) for a period of 7 days.
Can you have polished concrete outdoors?

Yes. For outdoors however we would not normally recommend a Mechanically Polished Concrete. The alternative for these areas are honed concrete or a grind and seal. The reason for this is to provide alternatives for a more slip and UV resistant finish. Honed concrete or a grind and seal with an epoxy or polyurethane coating are ideal for driveways, outdoor areas, concrete around your pool, garages etc.

Is polished concrete cold during winter?
Polished Concrete is recognised as being a sustainable and environmentally sensible building product, and this is largely due to its thermal mass properties (which is the ability of the floor to absorb heat and release it slowly). Therefore, in winter if a concrete slab gets warm during the day, it will release this heat slowly at night.
What colour choices are available in Epoxy flooring?

Epoxy colours have almost as much colour choice as paint – there are many options available. Please see below chart.

colour-chart-1 colour-chart-2

What can you do about oil stains on a garage floor?

If you want polished concrete on your garage floor we will grind the top coating off first which will remove some staining. If the oil is still present we can do a procedure called a purge – and we can do this a number of times to bring the oil out of the floor. On most occasions the combination of grinding and purging will remove stains from your garage floor, however we cannot guarantee results. If staining is unable to be removed we would recommend using a solid colour epoxy coating similar to the below image.

garge-floor-grey-epoxy-coating

Can you make our polished concrete floor non-slip?
As a general rule Mechanically Polished Concrete is slip resistant – but like many other flooring options it will be slippery when wet. If you need a flooring that is non-slip we would recommend doing a Grind and Seal method of polished concrete or another type of coating like an epoxy. With these flooring options we can add a grit to the top layer which can give a non-slip finish. These are ideal for wet areas, around pools, outdoor areas and other commercial environments.
What type of flooring would you recommend for an industrial setting?

Industrial flooring needs to be hard wearing, usually slip and chemical resistant and durable.  With this in mind we would normally recommend an epoxy coating or polished concrete flooring – We at OzGrind are experts at both and it would be best to give one of the friendly staff a call to learn more.

If I’m building a new house, at what stage is it best to get the concrete polished?

OzGrind should be consulted from the very early stages of the build – we have some information that you can give to your concreter which informs them of the best way to pour the slab so that you will get the best results.

For us to come and actually do the polish it is much better for everyone if we come in after the frame is up, but before the skirting and plaster gets done.

Will you do work rural & regional areas in Queensland?

OzGrind will perform work in Brisbane, Gold Coast & Sunshine Coast at our standard rates. OzGrind is willing to travel for work outside of these areas to rural & regional Queensland, however accommodation and travel surcharges will apply.

Is polished concrete expensive?

Mechanically polished concrete has a minimal lifetime cost (see below comparison to other flooring options). There are too many options and variables to answer this question in this section. Polished concrete is not a mass-manufactured product that is simply installed, it is a process of grinding and polishing an individual concrete floor. Factors that will affect the end price include how open the floor plan is (so that the grinders and equipment can access all areas easily otherwise hand work needs to be factored in), the condition of the floor, if it is a new or an existing slab, and how elaborate any decorative options might be, like how much stone exposure you want visible, and what gloss level you want. To get the best idea of how much polished concrete will cost on your floor, it is best to speak to one of the team at OzGrind.

chart

Can you choose the colour of the polished concrete?

If you want to polish the concrete of an existing slab then you are limited usually to whatever is already in the concrete.  Your only real option if you don’t like the colour or the cement and aggregate is to put a colour dye over the top.

If you are pouring a new slab you can choose the colour of your cement and the colour of your stone (aggregate)  there are a number of concrete suppliers you can visit. Some examples are below…

It is important not to underestimate the colour of the cement as this can significantly change the look and the cost of the floor.  Below is an example of polished concrete sample using the same stone but changing the colour of the cement:

How long does concrete polishing take?

The time it takes to polish concrete depends on a few factors – firstly of course how big the area is, and also if the space is open or if there are lots of small rooms that require hand work, then it depends on which concrete polishing procedure you want – hiperfloor or grind and seal, then how much exposure of stone you want to see, and the level of shine you want.  But as an example a normal double garage for a grind and seal is usually completed in 2-3 days.  And for a house that has approximately 100m2 of hiperfloor allow 5-6 days.

What does polished concrete cost?

It is usually worked out on a square meter rate, and price again depends on the procedure – hiperfloor or grind and seal, level of exposure, condition of the concrete etc.  It is best to ask us for a quote.  Any jobs that are under 30m2 usually end up being a job rate rather than per square meter.

Can I have polished concrete in wet areas? Shower bases etc?

Yes it is possible, but we would recommend doing a grind and seal instead of a hiperfloor.  With the grind and seal the topical sealant will be water tight so no water penetrates into the concrete.

Is there much mess or dust during the concrete polishing procedure?

When doing the main grind there is very little dust in the air as we use high-grade dust extractors.  There is a minimal amount of dust created when using the hand grinders if required.  After each step during the procedure the floor is cleaned and on completion there is no mess or dust to be seen.

How do I clean my polished concrete?

The best way to keep your polished concrete in good condition is to use a ph neutral cleaner followed by clean water for spills, otherwise a microfiber mop will get rid of dust.

Can you do repairs to our existing polished concrete floor?

As a general rule yes.  Hiperfloor can be repaired easily in small areas, however with a grind and seal entire areas usually need to be done to avoid any differentiating spots.

If I am pouring a new concrete slab, when is the best time for the concrete to be polished?

It is best that we get in touch with your concreter as soon as possible.  But as a general rule the concrete should be cured for 28 days before we get on and grind.  Then we can do the polish all at once or in two stages.  If we are to do the procedure in one stage then we come in after the frame is up and internals are water tight.  Or we can do it in two stages which requires us to come in and do an initial grind and grout prior to the frame being erected, then we put on a protective coating until works have been completed up until just before the plaster, then we remove the protective coating and polish up the floor.

Do you pour the slab?

No, we generally just do the polishing or grinding, however we do have some concreters that we work closely with and can recommend to you.

Does polished concrete really save on lighting costs?

Yes there have been customers that have stated it has saved them over 50% on electricity bills due to the reflectiveness of the surface.

Will it feel cold to walk on with bare feet?

Surprisingly NO.  Unlike tiles that have a small thermal mass, due to the size of the slab it is a good insulator and therefore will feel much warmer than tiles to touch.

What about cracks in the concrete?

Part of our grouting procedure can actually fill in small cracks, and if you choose a hiperfloor the procedure actually hardens the top surface by up to 10 times its natural strength.  If any cracks do appear we can generally repair them.  However it is concrete and you can never guarantee that it wont crack.

Is polished concrete slippery?

Generally speaking, it is no more slippery than other hard flooring surfaces.  Add water to it though and like any other surface it will be slippery.  That is why we recommend for outdoor use to do the grind and seal procedure – this way we can add an anti-slip agent to the sealer.  We can tailor the anti-slip to your needs, meaning that we can add a lot or a little depending on the result you require.

Will my polished concrete stain if I spill something on it?

Generally speaking it should not.  We do use a sealer on all our finishes which prevent staining.  However we do recommend that spills are cleaned up quickly.

How do I maintain my polished concrete?

This depends on what procedure you have done.  Grind and seals will need to be resealed every 2-10 years depending on the quality of sealer you have selected, and if you leave it too long you will need to have the floor re-grinded and sealed again.  For hiperfloors generally you can just reapply the protective sealer every 10 years.

Is polished concrete environmentally friendly?

Yes, often polishing jobs are done on existing concrete which is made from the most common mineral on earth – limestone.  Concrete can also be made from waste byproducts and newer concrete may have metal, marble chips or recycled glass which reduces the amount of waste in our environment.  Concrete is a very small contributor to greenhouse gases, and will outperform timber, steel, carpet and tiles.

I suffer from allergies and asthma, is polished concrete a good solution for me?

Yes, in fact it is one of the best solutions for you.  Polished concrete floors will not support the growth of toxic mould, dirt, pollen or dust mites and therefore are perfect for any sufferers of asthma or other allergies.