When undertaking a paving project, before you begin marking out an area or pick up a single tool, there is something to consider before that – which material are you going to use?
It’s important to work out for yourself, or for your client, exactly which paving is going to be the most suitable. Each material type has unique characteristics and style. Some are more hard-wearing, others have more colour variations and often the surface finish of one material can be different from another.
If gardening is your main hobby, the best option for you is likely going to be different to someone who will use his garden for entertainment. It’s important to know the difference between each type of stone in order to make a suitable choice.
Read on to find out which natural paving slab type may suit you best!
Natural Stone Paving
There are many stone types available, but we are of the belief that there is nothing finer than natural stone when deciding what to work with. It’s been around for 1000s of years with many of the modern wonders of the world being built with it.
It lasts for YEARS and will certainly last for years more if it is of good quality.
The colours in natural stone have been produced in the earth and not by a man-made process so the results are incredibly difficult to replicate by hand and eye.
Natural stone is often considered a superior product to its concrete counterpart for a number of reasons:
- It ages better with time.
- The colours are subtle and more varied.
- More frost resistant than concrete.
- Easier to clean.
- Considered more valuable and can even add value to a property.
Because the stone is all uniquely formed under the layers of earth, no two pieces will be the same. Each piece will contain its own unique layered patterns and veining, meaning technically each and every project will be unique.
Perhaps surprisingly, the process of quarrying natural stone is much more environmentally friendly than the concrete manufacturing process.
Concrete manufacturing process involves incredibly high temperatures when forming, which pumps out a large amount of CO2 into the atmosphere. So those with an environmental conscience may also favour natural stone.
The 4 types of natural stone we stock year-round are:
Each of the above natural stone paving slab materials have different properties, and it’s important to know the difference.
Indian Sandstone Paving Slabs
This timeless material is easily the most popular imported material available on the market. Sometimes known as "riven paving slabs", due to their huge array of colours, surface finish and general availability, Indian sandstone paving slabs remain an incredibly popular material to work with.
Sandstones are composed of tiny grains which are held together by a form of cementitious material which usually consists of silicon. It’s this silicon ‘cement’ that determines how resilient a material is.
Silicon is a tough material, which is why sandstone can be a very hard stone. It’s all to do with how tightly these silicon molecules are packed together.
The tighter they are packed, the harder the material. For example, Raj Green sandstone is very tough because the molecules are tightly packed together. Whereas something like rainbow sandstone, whilst more colourful because you can see the layers, they are not as tightly packed together. This makes rainbow natural sandstone a softer material to work with. This silicon ‘cement’ can be any number of colours and as a result, is what gives the slabs such a varied colour range – from grey to bright red – and whilst there is a variation in colour and make-up, you will find sandstone long-lasting and durable.
Pros & Cons of Indian Sandstone Paving Slabs
- Strong colour patterns and designs for each individual slab.
- Huge range of colours and styles.
- Wide availability.
- Easy to work with – cutting & laying.
- Will withstand the weather and frosty conditions.
- Dirt cleans off relatively easily.
- Lasts a lifetime whilst adding value to a property.
- Can fade over time if not looked after due to bad weather.
- The surface is 100% natural so can sometimes be a little over-rough on the surface.
- Natural stone also throws up the occasional undesirable natural variations such as blotches and other imperfections.
Whilst there are some drawbacks – in general, Indian sandstone is always an easy material to recommend.
Indian sandstone paving material is a well-rounded, colourful stone that survives well in the British weather and always looks great with a fairly low-maintenance regime.
Limestone Paving Slabs
Not entirely dissimilar to sandstone, limestone is also an imported sedimentary stone formed by tiny grains formed naturally under the earth.
The slight difference in geology is the cementitious material that binds the tiny grains together under pressure – it is a mixture of silicon and lime rather than purely silicon which creates the difference in colours and textures.
In addition to the colour, the more consistent grains mean that the surface of the limestone is also smoother. Whilst not perfectly smooth like a honed slab, a limestone slab’s surface doesn’t show the riven finish that is common in sandstone. It’s a ‘naturally smooth’ surface which only goes to add to the uniformity of the area.
Limestone is formed after many years at the bottom of lakes, rivers or oceans after the accumulation of shells bones and other calcium-rich minerals have caused pressure at the bottom of these bodies of water and formed these minerals into a stone. If subject to even more intense heat and pressure for long periods of time, the un-quarried stone metamorphoses into marble.
Limestone paving slabs are fairly impervious and hard. Other than exposure to acid, limestone deals fairly well with the elements, however, it will fade over time when exposed to direct sunlight.
Pros and Cons of Limestone Paving Slabs
- The texture of limestone is very fine, so it takes on a distinctive, soft-looking finish when used as paving slabs and results in a smoother surface.
- Even colours for creating a uniform area.
- Very easy to cut and work with.
- When the colour of the slabs is enhanced, limestone creates deep, unique and striking colours.
- Much more susceptible to colour fade than sandstone if not maintained.
- The colour palette is much more limited than sandstone and there are fewer ranges available.
- Acid damage is common because of the calcium composition. Be careful if it remains untreated.
Overall, limestone is a great choice because it is easy to work with. The colours are consistent and interesting. The composition of limestone creates a limited but attractive colour palette that brings any area to life.
However, because of its susceptibility to fade and acid damage, it is probably one of the most important stones to consider sealing.
For more information, read our Limestone Paving guide
Slate Paving Slabs
The colour palette of slate paving slabs tend to be subtle and beautiful. Riven Blue Slate, for example, is a colour that has been formed underground over 1000s of years and it is incredibly difficult to reproduce naturally. The subtle blues within the stone really draw the eye. Even the imperfections that occur in some slates are attractive – rustic slate ranges have layers of copper and iron colours that age the stone and simply can’t be replicated by hand.
Slate is a little different to sandstone and limestone. Both sandstone and limestone are sedimentary stones formed in grains, whereas slate is a metamorphic stone formed in layers.
The above distinction has an impact on the usage and properties of slate paving. Slate forms in flat sheets when the pressure of the movement of the earth’s crust squeezes the minerals into parallel layers.
Because of the layers, an important thing to remember is to always buy calibrated slate.
There are slates that come from all over the world, which vary in quality – so it is important that you know what you are buying:
- Chinese Slates - not always a good choice, initially once installed they look great but this appearance can soon deteriorate. This slate paving has a high lime & salt content within the slate & over time white blooming will show itself on the surface as efflorescence. It may start off as small patches appearing, but over time as water-soluble salts move through the material they carry the salts to the surface. The water then evaporates and leaves the white powder behind. Iron Pyrite (also known as fools gold) is also very common in some slate paving, especially in Chinese slate paving. The form of iron pyrite found in these slate pavers can rust very heavily when wet & cause bleeding patches of rust to appear over the surface.
- Indian Slate - Indian slate pavers are a good choice, again more so in the darker colours especially black pavers. Light coloured slate from India has a tendency to be quite soft & over time its layers can delaminate easily, so you should stick to a dark coloured slate. Again iron pyrite is evident in these slate slabs but to a lesser degree and in much smaller quantity. Overall Indian Slate Pavers are a good economical option.
- Brazilian Slate - Some of the best slate paving on the market has to be Brazilian slate paving. These slate pavers are very flat with no large clefts & can be hand split to almost any thickness. Brazilian slate pavers tend to be very clean and free from high lime and minerals and iron pyrite is not evident in this slate paver. Overall, Brazilian slate paving is considered to be the best material available for using externally.
Pros and Cons of Slate Paving Slabs
- Standout texture and colour which also doesn’t fade as quick as limestone.
- Very durable when used as external flooring.
- Low absorption rate which stops the pores from absorbing water which creates damage.
- Can be difficult to install if you don’t buy the right stuff.
- The layers can flake off if affected by the weather which creates pits for water to pool.
- Generally susceptible to moisture damage if left untreated.
Overall, slate is a fantastic choice. The colours and the textures effortlessly create a beautiful area that really draws the eye.
Some people recommend that slate is only used in smaller, focal points of the garden due to susceptibility to water damage.
However, this does seem overly cautious as we’ve not had any reports back of such issues. Because of the amount of effective treatments that are available and recommended for natural stone, we feel this is an easily addressed issue.
Granite Paving Slabs
Granite is a much different stone from the others. It is the only igneous stone that we have available and it is by far and away the most durable. The surface of granite paving slabs can come in a huge range of colours and finishes from white to black.
Because granite is tough, it cuts incredibly cleanly. Granite paving slabs come with 6 sawn sides and a surface finish such as flaming or leathered to give an abundance of looks.
Granite forms from the crystallization of magma below the earth’s surface and mainly composes of quartz and feldspar. Both these minerals – especially quartz – are incredibly hard-wearing and these are exactly what gives granite its incredibly hard nature.
Granite has the lowest porosity of all our stones – starting from around 0.2% porosity. It means water is mostly unable to permeate the granite. Additionally, it is highly thermally stable, so it shows no change with temperature.
What's more, granite paving slabs are highly resistant to chemical erosion. These properties make granite a great choice if you are looking for a long-lasting, durable stone.
Due to it being so tough, it's also incredibly difficult to quarry at high volume. Therefore it's actually quite a rare stone and often doesn't hang around long once it is quarried. It is currently only available as granite cobbles currently.
Pros & Cons of Granite Paving Slabs
- Granite is non-porous, which means the surface will not be damaged by water or by scratching.
- It’s difficult for the surface to retain dust and dirt and as a result, it is easy to clean.
- Huge range of colours. You can choose from dark black, through greys, pinks, reds and white.
- Incredibly weather resistant so will retain its value and look for years.
- Difficult to work with if you end up needing to cut the stone because of its hardness.
- Granite slabs are really heavy, so the task of laying them can be labour intensive.
Whilst granite comes at a premium price, the finish is stylish & incredibly low maintenance.
If you are looking to install this, the work is guaranteed to last for a long time simply because the stone is simply so durable. Despite the stone being heavy and difficult to work with, if you chose to install it – once it’s down, it’s not going anywhere!
For even more information, read our granite paving slabs guide
Porcelain Paving Slabs
Porcelain paving is going to be the only non-natural stone that we feature here. Currently - and likely indefinitely - outdoor porcelain paving is the only man-made product that we stock and sell. However, we felt porcelain was one worth making an exception for.
It solves a lot of the cons of natural stone we've discussed up until this point, so it is well worth discussing as an option.
Outdoor porcelain tiles are manufactured by firing clay at very high temperatures using moulds, which results in identical slabs in the desired shape. Once these shaped tiles are completely dry, they are then wrapped in a veneer to add texture and pattern. The pattern can be absolutely anything you can imagine - it can be made to replicate natural stone, but can even be veneered to look like deck boards!
The beauty of porcelain is that it addresses an awful lot of the concerns that natural stone can raise. Porcelain is described as an ultra-low maintenance solution as many of its properties means that once it's installed, there's not too much you need to do with it.
The porosity of Porcelain slabs is close to 0%, which means that it won't absorb stains and muck at all. If you wash down a porcelain patio even years later, it should come up looking like the day you installed it. On top of this, Porcelain tiles are incredibly hard-wearing and truly stand the test of time. They are scratch-resistant and able to withstand a lot of pressure - they are a real top-of-the-range option.
However, it's important to remember that this is no longer a natural stone and there are drawbacks that come with it. There is an extra step that comes during installation: as the stone is non-porous, it struggles to stick down to a mortar bed on its own. There is an extra substance known as a "primer" that needs to be added onto the bottom of a porcelain slab to enable it to stick down to the bed. So it is a little bit more involved during installation.
Also during installation, Porcelain paving slabs can be much trickier to cut than a regular Indian sandstone for example. They are very tough and long-lasting, but naturally, this makes cutting them more difficult. With a specialist blade, a lot of the hard work can be done for you, but it's important to note the extra blade requirement.
Pros & Cons of Outdoor Porcelain Paving
- Porcelain is entirely non-porous, which means the surface will not absorb stains or be damaged by water.
- Super-easy to clean.
- A wide variety of options due to the flexibility of using a veneer.
- Strong, long-lasting tile that will come up brand-new after cleaning.
- Difficult to cut and requires a specialist blade.
- Extra later known as a "primer" is needed to make sure the slab adheres to the bed.
- Top of the price range.
Porcelain is increasing in popularity dramatically - what was almost unheard of as little as 5 years ago has now become one of the market-leading options for outdoor paving.
Porcelain is a pricier option that is trickier to install than a natural stone. But once it's done, you will be absolutely over the moon with the finish along with the 100s if not 1000s of others that have gone with the porcelain option.
Stone Paving Slab Types: The Summary
There are a number of materials that these slabs can be made from, and as a result, there are different slabs that are likely to be suitable for different projects.
We hope this has made it clear what each type of natural stone paving can be used for and what might be the ideal choice for you and your project!