Characteristics of Natural Stone

Natural Stone offers a diversity of product and colouring that will give you an immense variety of landscaping options!

Then why use Natural Stone? Here are some of the reasons why:

- Will age well and improve the way it looks with time
- Unique blend of colours and tones per piece of Natural Stone
- Easy to clean
- Durable frost resistant paving
- Adds great value to your property just or using Natural Stone

However, it's important to have an understanding of the characteristics of Natural Stone, to ensure that you buy the correct product to meet your expectations . There are various feature to be found in Natural Stone that should be embraced as part of the product rather than being considered as imperfections.

Have a look below at what to expect:

Examples	Causes	Solutions/Prevention
Green Staining	- Shaded areas on the paving that cannot dry - Water that sit in poorly drained areas. - Moss and algae that can thrieve in damp areas. - Extract from fallen leaves. - Staining can also be yellow and black, but usually green.	- To sweep your paved area will reduce the chance of growths. By using bristled brushes you reduce the chance of scratching the surface. - Regularly maintain overhanging shrubbery to allow sunlight and air onto the paved area. - If staining occurs, there are specialists and cleaners that will be able to resolve this type of issue.
Efflorescence	- Typically a naturally occurring phenomenon where salt from the bedding materials migrates up through the stone and appears on the surface. - Will leave white marks on the surface of your stone	- It is a natural occurrence that cannot be prevented, and usually appears shortly after laying. - It may wash away over time with weathering. - Specialist and general cleaners are on the market which are known to tackle this issue. - Check the data sheet for compatibility with your stone and carry out a trial area first.
Black Staining	- Caused by colonies of black Lichen on the stone. - The Lichen will feed off the minerals in your natural stone, eventually burying themselves further down into the stone over time, making them dif cult to remove. - Can appear as black spots or as larger black stains.	- Regularly sweep your paved area to avoid growths from taking hold. Only use soft bristled brushes on natural stone, as wire brushes will scratch the surface. - Once staining has occurred, there are specialist and general cleaners on the market which can tackle this type of staining. - Check the data sheet for compatibility with your stone and carry out a trial area first.
Iron Imperfections	-Orange staining can appear on a stone where Iron is present. This can be from within the stone itself, or from an external source. - Some stones contain iron naturally, and stone can weather over time to reveal these orange markings. - There is a threat of orange staining when using weed killers and fertilisation products near your natural stone. Take extra care when using these sorts of chemicals around natural stone. - Staining can also occur from metal structures left on the stone. When the metal reacts with water, it will begin to rust and leave a stain on the stone.	- There are cleaners available on the market which have been known to resolve this type of staining in some cases. - Check the data sheet for compatibility with your stone and carry out a trial area first. - Take extra care when using fertiliser around natural stone. Even once the chemicals have been sprayed, the rain can wash them onto your natural stone which can result in staining. - Do not leave any metal garden furniture or sculptures on your natural stone for long periods of time. Regularly move the furniture and clean the paved area.
Through Bed Staining	- This staining is the result of water soaking through the stone and reaching the mortar bed, making it wet again. - Results in ‘damp’ looking patches on the surface of the stone. - This is more likely to occur if the agstones have not been installed on a full mortar bed.	- When installing natural stone, lay on a full mortar bed. This will not prevent through bed staining, but will reduce the chances the of it taking place. All good practice guidance suggests that paving should be fully bedded and not laid on dots and dabs. - On light coloured stones use lighter coloured sand and cement. - Consider using a bonding slurry. - Try a test piece before undertaking full project.
Weathering	- Weathering is something that cannot be prevented. As the stone is exposed to the elements, over time it will weather and it can change in appearance. - The stone can be expected to change in colour slightly. For example, some of our Grey stones have been known to reveal some brown/orange hues after weathering. - Some products may fade with weathering, especially in sunnier climates. Black stones have been known to weather to a dark grey colour.	- Weathering cannot be prevented.• Sealers are available on the market which can help the stone retain it’s colour, preventing or delaying the fading process. - The sealer will need to be re-applied regularly as part of a planned maintenance regime. - Products are also available on the market which can restore faded colours already lost to weathering.
Delamination	- Delamination is typically water and temperature related and can be linked to a number of causes including moisture sensitive minerals aligned with the natural bedding or cleavage in a rock. This is usually more evident in slate which often has a repetitive thin layering but can be seen in some sandstones. - The surface of the stone can ake away, exposing the next layer of stone underneath, leaving chips of stone loose on the paving.	- As this is a natural occurrence, it cannot be predicted or prevented.
Surface Imperfections	- These can appear in the form of small brown marks or pits on the surface of the stone. - Can often be the result of small mud lenses naturally present at the surface of the stone. - Weathering of the mud lens can result in the development of a small hole or pit. - Some sections of stone may never reveal an imperfection, whilst others can weather and reveal themselves after days, month’s or years.	- Natural stone varies in it’s makeup, it cannot be predicted what is within every piece of stone and how it will react to wearing. - Should an imperfection weather on the surface and leave a hole, there are specialist llers on the market to resolve this issue.
Salt Damage	- When in contact with stone, water containing salts may penetrate deep into it, eventually evaporating and leaving behind salt crystals. These crystals continue to grow within the stones structure. - Over time the crystal growth will cause expansive forces that can result in the breakdown of the structure of the stone, often causing cracks and chipping on the surface of the stone. - The stone surrounding the pool will become chipped, and weathered in appearance.	- Take expert advise on the pool system used to prevent this issue.

Characteristics of Natural Stone - What to expect

Examples

Causes

Solutions/Prevention