Frequently Asked Questions (FAQ)

Questions and Answers

Starting your Geostone project

Exposed – Created by washing off the top layer of concrete to reveal the stone, Geostone exposed provides a skid resistant and durable finish that is ideal for outdoor applications such as driveways, pathways and other external areas.

Polished – Achieved through grinding and polishing the concrete to create a highly glossy finish, Geostone polished is perfect for any internal room of the home.

Honed – Honing is achieved through grinding the top layer of the concrete to reveal a natural stone and a flat matt finish. With a similar level of comfort underfoot to Geostone polished, and with the practicality of Geostone exposed, it is perfect for alfresco, entertaining and pool areas.

To read more about the difference between honed and polished concrete click here.

Coloured – Created through adding fine particle colour pigments at the mixing stage to create a full depth colour concrete that once sealed is weather and UV resistant, making it ideally suited for driveways, pathways and outdoor entertaining areas.
Visit one of our national Display and Selection Centres to view the entire Geostone range available in your area. Call our Customer Service Centre on 13 11 88 to find your nearest Display and Selection Centre.
The stone in Geostone is a raw material and is selected for its natural variation in colour, size and shape, therefore some variation can occur from batch to batch and such variations can influence the overall colour and appearance of your finished project.

Where the concrete is placed can also have an effect on the final appearance; concrete placed in shaded areas can appear different to concrete placed in direct sunlight, and concrete placed in cold conditions can appear different to concrete placed in warm conditions. Additionally, variation in the exposure level (e.g. the volume of stone showing or the extent to which they protrude above the concrete) or, inconsistent levels of stone exposure on a project, can also result in colour variation.
Yes, but be aware that as Geostone is a natural project, completing a project over a number of days can result in colour variation. Talk to your installer and make sure they take into account weather conditions as well as staging the installation if you are placing Geostone in a few different areas of your home (e.g. one day for the driveway followed by another day for pathways) to reduce the appearance of any variation that may occur.
Call the local Customer Service Centre on 13 11 88 for a list of installers in your local area. When choosing an installer we recommend you always ask for recent customer references and view some of their recently completed work. Remember to make sure both you and your installer agree on the desired finish and discuss any unique requirements for your project.
To place an order, call the Customer Service Centre on 13 11 88. To ensure availability, an order needs to be placed a minimum of 7 days in advance of the required delivery date. Remember to notify us if your project will be completed over a period of time.

Planning your Geostone project

It is quite common (and recommended) for concrete projects to be engineer designed. You may wish to consult with a structural engineer at the outset to specify and design your project, this is particularly vital for internal flooring and commercial projects.
It is important that the area where you are going to install your Geostone concrete has been properly compacted. The process of compacting pushes the soil particles together to create a more stable subbase. Be especially aware that areas that have been excavated alongside buildings, retaining walls and pipework are often poorly compacted and will require special attention. We recommend contracting a professional to assess the compaction of your project. Aside from issuing a compaction certificate, you’ll have peace of mind that your site is well prepared and ready to go.

Once the area has been compacted, it needs to be well watered prior to your installer coming on site (unless you are using plastic or ‘poly’ beneath your concrete or otherwise advised by your installer).

Minimising the risk of cracking

It is essential to use steel reinforcement to provide additional strength and to assist in the control of natural movement which can lead to cracking.
Your installer must use commercial bar chairs designed to hold the steel reinforcement above the ground when placing the steel mesh. This is essential as it ensures the steel reinforcement is installed in the upper part of the concrete where it is most effective.
In the first instance, always consult with your engineer, architect or designer. We recommend for external areas, SL62 (or higher), and for internal polished or floating slabs, SL82 (or higher).
As concrete is highly alkaline, the steel will not rust provided that it is fully encased by the concrete. The reinforcing mesh should be placed a minimum of 25mm away from the concrete surface to ensure it won’t come into contact with the atmosphere.
Where possible, it is better to avoid pouring on days of high temperature or high wind as your concrete may dry too quickly which can lead to cracking. If it is critical to pour on such days, it is essential that the necessary steps are taken to prevent rapid drying. Discuss with your installer what steps will be taken to prevent rapid drying on your Geostone project.
Using a water vapour barrier, such as plastic or ‘poly’ under the concrete can help prevent cracking as it reduces movement and friction between the concrete and the ground below. Additionally, it will also help to protect your concrete from possible discolouration caused by underground water, dampness or water logging. Talk to your installer to see if this solution is suitable for your Geostone project.
The curing process protects fresh concrete from rapid moisture loss and extreme temperatures; this both reduces the risk of cracking and increases the strength of the concrete.
For decorative concrete, we recommend your installer use the membrane method of curing by applying a single coat of solvent-diluted acrylic sealer (sometimes referred to as ‘same day’ sealer). Normal pond curing (where sand and clay are used to create ‘ponds’ which are filled with water) is not recommended as the sand and clay can cause staining of the concrete and affect the appearance of your Geostone concrete.
Control joints are placed in the concrete to encourage any cracking that may occur to happen in predetermined locations, allowing the customer to control to an extent where the cracking happens and reduce cracking as much as possible given the terrain.
Control joints should be planned at the outset and placed at aesthetically appropriate areas. For Geostone projects that are 100mm deep, we recommend that control joints be spaced no further than 2.5 metres apart. When planning your project with your installer, you should aim to achieve square rather than elongated shapes with your control joints. It is important that the reinforcing mesh also be cut at the points where control joints will be placed in order to enhance their effectiveness.
We recommend that control joints be cut by trowel or jointing tool whilst the concrete is ‘plastic’, or by saw no later than 18 hours after the concrete is laid. While control joints can be cut by saw, this can introduce unwanted moisture into your concrete which can later produce a milky colour on sealed concrete. Saw cut joints may also introduce foreign material such as sand which can allow weeds to grow causing the edges of the concrete to crack. Commercial coloured seals are available to cover saw cut joints and prevent these issues. Alternatively, your installer may supply one of several commercial jointing products.
We recommend that control joints be cut to a minimum of 25% of the concrete depth in order to be effective.
Please consult with your structural engineer or builder.

Installing and creating the Geostone look

We recommend avoiding adding water to the mix as this will affect the colour, finish and strength of your concrete.
Only commercially available retarders (a chemical used to prevent the top layer of concrete from hardening) should be used when exposing the stone in your Geostone project. Sugar should never be used as a retarder as it has been our experience that it will not achieve a consistent result. Your installer should include the cost of retarders in their quote.
The level of exposure can be controlled; light exposure reveals a few stones in the surface while heavy exposure creates a more coarse effect with more stones protruding from the surface. Make sure you discuss the options with your installer before starting your Geostone project.

Maintaining the Geostone look

As concrete is a porous material it can absorb contaminants which can lead to staining if not treated. Not all installers include sealing as a standard so make sure you ask your installer about sealing at the outset of your project.
We recommend resealing your Geostone concrete every 2 years to keep it looking the way you want it to. Keep in mind this depends on the amount of traffic and resulting abrasion on the concrete surface.

Protect your local environment and waterways

The process of exposing aggregate and grinding polished or honed concrete floors produces sensitive waste materials such as cement slurries, care should be taken to retain all waste on site and then dispose of it in a responsible manner. Contact your local council for more information.

For further information please refer to our Best Practice Placement Guide or contact your local Geostone representative.