Frequently Asked Questions

1. What is Efflorescence?
2. Laying pavers on Concrete Slabs
3. Sealing
4. Cleaning
5. Will my floor have an uneven surface?
6. What guarantee is there that the colour will be consistent?
7. Will the surfaces wear out or chip?
8. Will the surface flake or break away?
9. Will stone surfaces survive a fire?
10. What products are the safest surfaces around pools?
11. Are light colours better suited to outdoor areas?
12. How does well does stone resist salt attack from swimming pools?
13. Can stone be used on bathroom floors?
14. Can I use stone outside in frost areas?
15. Is slate a good outdoor surface?
16. Are stone floors cold to walk on?
17. Does under-floor heating work with natural stone surfaces?
18. Do they need to be graded before laying or fixing?
19. Should I lay tiles randomly or sort them for colour?
20. What adhesives should be used to lay or fix?
21. What is the best way to cut natural stone?
22. Can natural stone and slate tiles be laid on backing panels?
23. Do I have to seal flooring products?
24. What type of sealant should I use?
25. How often do I need to seal?
26. Sealing pool surrounds?
27. How can I remove marks and stains from natural stone?
28. What is the best way to clean my slate floor?
29. How do I decide which type of paving will suit my project?
30. Is paving the same as concreting or stencil-crete?
31. Why is paving a better option than concrete?
32. How long will my paving last?
33. Will I need to get my new pavers sealed?

What is Efflorescence?
Nearly all pavers can be affected by (usually) white salt that deposits on the surface as a stain or powder. This is called efflorescence and it results from excess salt content either in the paver itself or possibly the material it is laid on. It is promoted by dampness and poor drainage so trying to hose it off will be futile. It is usually only a temporary problem and will eventually disappear once all the salt has worked its way out but cleaning agents are available at Domain Paving that will help to remove it sooner.

Laying pavers on Concrete Slabs
Concrete can be an excellent base for pavers eliminating the risk of subsidence. But if the pavers are laid on sand over concrete, it is important to endure that the slab is drained so rain water does not hang around in the sand bed. This could result in chronic efflorescence or other stains such as “picture framing” at the edges of the paving that can be difficult to remove. This can be avoided by drilling holes in the slab at the low points or sloping a poured slab towards expansion gaps that are then left open to be filled with the bedding sand.

Sealing
It is always beneficial to seal pavers to make it easier to keep them clean. Broadly speaking there are 2 types of sealer: Surface and Penetrating. Surface sealers usually darken the appearance of the pavers and care should be taken to ensure the pavers are clean and dry and any efflorescence has been eliminated before sealing. Penetrating sealers do not noticeably change the natural look of the pavers and will allow them to “breath” and continue to release any lingering efflorescence.

Cleaning
Generally the simplest way to clean pavers is with domestic strength water blasting, especially if the pavers have been sealed. Other cleaners are highly effective for more difficult problems like algae or mould. Some stains, such as cement grout, rust, oil etc may only be susceptible to acid cleaning. It is important to use acid carefully on all pavers and to consult our experts on the correct type of acid cleaner to use and methods of application.

Will my floor have an uneven surface?

Some projects are suited to uneven surfaces whilst others require a smooth finish which is achieved by using stone that has been honed. Naturally split material is very popular for use in areas where a non-slip surface is required. It is especially popular on outside areas such as patios, steps, pool surrounds and driveway applications. There are processes that can be applied to the surface of the material to give it a more uniform and luxurious appearance such as honing.

What guarantee is there that the colour will be consistent?

Natural stone varies in colour due to the different hues of the natural particles that make-up the product. Unlike man-made products, no dyes or artificial coloring agents are applied to homogenize the products – a manufacturing process that often results in loss of character.

It is the variation in natural stone that makes each project quite unique. The colour variation also allows previously laid areas to be seamlessly extended many years later without obvious colour change.

Will the surfaces wear out or chip?

Natural stone is tough and very durable so it is unlikely to wear out – one of the main reasons it is used in public areas. Some wearing is evident on the stairs of public buildings but it usually takes 100 years of heavy traffic to make an impression.

Natural stone will withstand a lot more punishment from hard objects than man-made products.

Will the surface flake or break away?

Naturally cleaved stone products can be subject to flaking but this can be easily prevented with the correct preparation. Flakes should be removed with a trowel or scraper, as the tiles are being laid.

If flaking should occur after laying, the surface may be stabilised by applying a recommended sealant. Surfaces will not flake if the tiles have been properly laid.

Will stone surfaces survive a fire?

Natural stone is impervious to fire and will lower the risk of fire damage in any building – it would be nice if it lowered your insurance premium as well – but it rarely does!

What products are the safest surfaces around pools?

The ability of a wet surface to provide a good safe, non-slip environment for traffic, especially children, around swimming pools is of critical importance.

Natural stone products are ideally suited to swimming pool surrounds because of their coarse and slightly uneven surfaces. The texture and surface finish of the stone is the key to it’s safety. Providing the surface is not polished the vast majority of stone surfaces are far safer when wet than the man-made article – especially for exuberant children who love playing around pools and who tend to run rather walk!

Sandstone, quartzite, travertine and limestone all provide good non-slip surfaces around pools, as do slates with irregular finishes. Natural split, tumbled, antique and flamed surfaces are most popular and provide good “grippy” surfaces.

The best guide to the potential slip resistance of a stone is the wet pendulum test results that are published on this website under the relevant material.

Are light colours better suited to outdoor areas?

Dark coloured objects absorb and retain heat more than light coloured objects. If the outdoor surface is exposed to light and is going to be walked on by people in “bare feet”, light coloured sandstone, quartzite or limestone are more suitable than the darker coloured slates.

How does well does stone resist salt attack from swimming pools?

Natural stone has a history of holding up well beside swimming pools but the resistance to salt attack depends on how close to the water the stone is fixed and how frequently it gets inundated.

Pool aprons that remain relatively dry will suffer least but pool coping on modern pool designs will be far more vulnerable because of their extremely close contact with the water and inundation from frequent lapping and splashing.

No stone is completely “salt safe” because all stone is porous and absorbs water but some types of stone perform much better than others. Granite and quartzite perform extremely well when used as pool coping. The benchmark guide for resistance to salt attack around salt water pools is a test result for weight loss of less than 0.1%.

Sandstone is quite variable in porosity and density so care needs to be taken in the selection of the stone.

Water soluble, penetrating, hydrophobic (water repellent) sealers are designed to form a barrier to prevent the entry of moisture into the stone but even the best sealants do not make the stone totally impermeable. Remember too, that penetrating sealants are designed to allow water vapour (i.e. water as a gas, not liquid) to move into and out of sealed surfaces and that any salt that penetrates the under-surface of the stone will remain trapped.

Sealing with a penetrating sealer (though not always recommended) will help protect your most vulnerable areas but they will only perform well if properly applied. Coping needs to be sealed top and bottom at least 3 times before fixing. In general, the best protection will be achieved by applying as many coats of sealant up to the point where the stone is not capable of absorbing any more. If the sealant is performing well, water will bead on the stone surface (and coping edge & under-surface) – failure to do so indicates the stone should be re-sealed.

Some salt water pool owners prefer to leave the stone around their pool unsealed choosing to hose down inundated areas after use. In theory, this may work well as the salt is soluble, however it would be almost impossible to remove all the salt and whenever salt crystallizes in any porous hard surface, even concrete – damage to it’s structure is inevitable.

Can stone be used on bathroom floors?

Most natural stone products are very suitable for bathroom floors but should be sealed with a penetrating sealant before use. Naturally split surfaces are most popular because they provide better traction. If there is concern about how slippery the surface may become check the surface treatment (natural split surfaces are generally safest) and refer to wet pendulum slip resistance test results (V = very safe is the best category).

Can I use stone outside in frost areas?

Stone is a wonderful product that will provide durable, long lasting surfaces in most areas – both inside and outside. Frost tolerance will depend on how much moisture the stone absorbs and how severe the freezing is and how long the temperatures remain below zero. In most parts of Australia frosts are mild and they dissipate before mid-morning the next day. Temperatures of -10 degrees Celcius will do far more damage than mild frosts.

Water trapped in the pores of stone when frozen expands then contracts when the temperatures rise above freezing point. This expansion and subsequent contraction over a period of time may weaken the structure of the stone and cause cracking. Stone laid under verandahs and porticos where it is protected from rain and frost is unlikely to experience any problem.

Stone varies quite widely in both density and porosity and this affects its ability to absorb and retain moisture. As a general guide, stone products that are dense (high bulk specific gravity test results) and have low water absorption rates will perform the best under freeze/thaw conditions.

Is slate a good outdoor surface?

Slate is a wonderful floor product for both indoor and outdoor use. Slate has been used as stair treads and risers on civic buildings for hundreds of years because of its durability and low maintenance costs.

Remember though that the darker coloured slates will absorb heat and will get hot if exposed to the sun. Slate surfaces under pergolas and verandahs look great, work well and are extremely durable.

Are stone floors cold to walk on?

Surfaces covered with natural stone are refreshingly cool in summer and sometimes cold in winter but they do hold their heat better than most man-made products.

Does under-floor heating work with natural stone surfaces?

Under-floor heating though not very eco-friendly, is incredibly effective with properly laid natural stone surfaces as the heat from the underlying slab radiates out, heating the surface.

Do they need to be graded before laying or fixing?

Products calibrated for depth make the laying much easier because of their uniformity. Natural cleft or un-calibrated products usually require grading – a process that matches the depth of one tile with another. This can be quite time consuming for big projects but the outcome is well worth the effort as the finished project looks far more professional.

Should I lay tiles randomly or sort them for colour?

All natural stone and slate products vary in colour and the way tiles or pavers are laid in relation to one another depends on personal taste. They may certainly be laid randomly however imbalances in colour on parts of the surface tend to occur due to the element of chance dealt by Mother Nature’s hand. Some kind of sorting or grading is recommended if a more uniform and harmonious distribution of colour is desired.

What adhesives should be used to lay or fix?

Adhesives have made huge technological gains over the last few years and some excellent products and good technical advice are available through your local tile supplier. In general, the adhesive to be used will be determined by the surface. Two part rubber adhesives are generally used for timber surfaces whereas concrete and fibro surfaces require quite a different product, so as always, seek advice before you buy!

What is the best way to cut natural stone?

The most effective way to cut natural stone products is with a wet saw using the appropriate safety equipment.

Can natural stone and slate tiles be laid on backing panels?

Yes they can, providing (1) an appropriate adhesive is used and (2) joints are properly taped to prevent tiles lying above the seams from cracking.

Do I have to seal flooring products?

Natural stone is tough and very durable but may need to be sealed depending on how it is used. Sealing is not always recommended for outside areas that are frequently inundated – it depends on the type of stone used and its environment. In general though, sealing is recommended anytime the stone is subjected to chemical (coffee, wine, salt) or biological (leaves, food) staining.

In other instances sealing may be a good option as it can enhance colours and make the surface easier to clean. In a kitchen or outdoor BBQ for instance, sealing is recommended as it will help prevent discolouration or staining caused by spillages.

If sealing, make sure the sealant is appropriate for the type of stone being used eg. sealants designed for marble may not be suitable for sandstone.

What type of sealant should I use?

There are different types of sealing products to give different finishes and you need to get good advice to ensure you get a product that suits your purpose. Penetrating sealer leaves the stone looking natural; while acrylic sealers highlight colours within the stone.

How often do I need to seal?

It is recommended that at least two thin applications of a good quality sealant be applied initially with follow-up treatments applied as needed depending on traffic and exposure to the elements. The initial applications need to be kept thin so the sealant doesn’t puddle in grout joints.

Ensure that the surface has been thoroughly cleaned to remove all dirt and grime before applying the first coat of sealer. Sweep and re-clean the surface with a neutral cleaner before applying subsequent coats.

After re-sealing your natural stone will look new again!

Sealing pool surrounds?

Salts from swimming pools can cause some types of stone to exfoliate so the choice of stone for use around swimming pools is critically important. The best indicator of how well a stone will perform in a pool environment is its test result for resistance to salt attack (see test results section).

There are big differences in the ability of stone to resist salt attack. Grey Gum & Sofala quartzites are very dense, durable stones with low water absorption characteristics and good salt resistance. Both are suitable for use around pools but should be sealed as a precaution.

Sandstone is extremely popular for use around pools but they are highly variable in porosity, density, water absorption and resistance to salt attack. Sandstone sourced from Rajasthan in India are far more dense than Sydney sandstone; tests reveal better potential durability. Some types of sandstone are not recommended for use around pools. It would be sensible to thoroughly seal sandstone with a water based penetrating sealer even if they have a high rating for resistance to salt attack.

Pool coping that is likely to be frequently inundated by splashing water should be sealed at least three times on all sides prior to fixing and re-sealed annually.

Make sure that any stone used as pool coping is thoroughly sealed under the exposed lip as any salt laden moisture that gains access at this point will be held in the stone. Eventually the water component will escape through the barrier created by the sealer just under the top surface of the stone, but the salt will remain.

Salt will cause damage to any hard surface not just stone. It will reek havoc with concrete if it can gain access – water is just its means of transport!  Water carries the salt into the minute pores of the hard surface and eventually the water evaporates leaving salt in crystal form. If the process is repeated the salt crystals get larger creating a force capable of damaging the structure of its host. The symptoms of structural damage are pitting, flaking and spalling.

Most pool aprons are a battle ground of physical (high traffic) and chemical (salt) forces and that is why annual re-sealing is desirable.

How can I remove marks and stains from natural stone?

You need to get professional advice for specific cleaning needs as there are hundreds of products available that are usually tailored to a particular type of stain – for example, grease, red wine, dirt or ink. Often a simple bleach or strong detergent will do the job.

What is the best way to clean my slate floor?

Some slate floors have an irregular finish that catches fibres from a broom or mop when sweeping or cleaning. The application of a high quality acrylic (surface) sealer will make the surface smoother and easier to keep clean.

White crystallized deposits have appeared from the grout lines on our patio steps, how can I get rid of them?

These white deposits are most likely salts that have originated from the mortar or grout joints. They can be scraped off with a paint scraper or washed off with a very mild acid solution, but seek professional advice first.

How do I decide which type of paving will suit my project?

There are many different surface finishes and colours that are available today from various manufacturers. The first step is to decide which size of pavers you like, namely large to medium format, or brick size.(ie large and square or smaller and rectangular). Next, look to the colours available to you from a particular paver range, and decide which colour(s) complement your project best.

Contact Domain Paving and have an estimator provide a written quotation to lay a specified type of paving to your project.

Is paving the same as concreting or stencil-crete?

No. This process involves pouring concrete in a slab form and either stamping a pattern into the concrete, or spraying a pattern onto cured concrete.  Paving comes in many different shapes and sizes. They are pre-cast, individual segments of uniform shape and size, and are laid one at a time in various patterns to suit the project needs or clients desires.

Why is paving a better option than concrete?

The choices of colours, textures, and formats make paving extremely versatile compared to all other hard surfaces. No concrete design can ever replicate the natural and unique look that comes with paving. Colours can be interchanged as well as sizes giving you the ability to do what ever your imagination desires.

How long will my paving last?

A quality paving job should last a lifetime. Pavers can be removed and replaced individually, should one or more crack, discolour or subside. You may need to access services underground, in which case access can usually be achieved without the need for machinery, saving you money.

Will I need to get my new pavers sealed?

Some manufacturers advise that their products are sealed once installed to increase their resistance to staining and marking. It is also dependent upon the application (ie driveway, oil stains, tyre marks, damp leaves) whether sealing is necessary. We always seek the professional advice of a qualified trade sealant company and suggest all customers do the same for such a specialized area