fbpx

Are you dreaming of the perfect patio to complete your home? If so, you might be wondering which paving material would be the best choice. 

Beautiful, durable and versatile, sandstone is certainly worth considering.

But what is sandstone and why might it perfectly complete your outside space?

What is sandstone?

Sandstone is a clastic sedimentary rock that is primarily composed of sand-sized silicate grains. There are many varieties of sandstone. Most are composed principally of quartz, feldspar or both but may also feature grains of other minerals like calcite, clay, or mica. Some 20-25% of all sedimentary rocks on Earth are sandstone.

Clastic rocks are formed from pre-existing materials rather than as a result of heat and pressure underground or chemical changes. 

Sandstone is created when sand is deposited by seas and rivers or in desert regions. The grains are later compacted and then cemented together slowly by minerals from groundwater. The resulting sandstones may be a variety of colours depending on their composition and where they were formed. The most common shades found are: tan, brown, red, yellow, grey, pink, white and black.

Quartz aronite – a stone primarily composed of quartz grains that is usually white or grey.

Arkose - a type of sandstone that contains a significant quantity of feldspar which gives the stone a pink or reddish colour. 

Greywacke - sandstone that contains a mix of quartz, feldspar and rock fragments. Greywacke sandstone often boasts a grey or greenish hue. 

Wacke - a type of sandstone that features a mix of quartz, feldspar and clay. 

Red sandstone – sandstone that has a reddish or pinky hue due to the presence of iron oxide.

Feldspathic Sandstone – a sandstone that features a large proportion of feldspar and that can vary in colour from light to dark.

Coconino Sandstone - found in the United States and particularly in the Grand Canyon, Coconino sandstone often boasts cross-bedding and features both quartz and feldspar.

side-view-sandstone-patio-photo-2

What is sandstone used for?

Used since prehistoric times, sandstone has been a feature of art works, tools, churches, temples, houses and other buildings. Today, it is also used as cladding for building facades and for paving. In addition, sandstone can be crushed to produce aggregate or gravel.

Why is sandstone so popular?

Sandstone has become an incredibly popular choice for all types of paving including patios. It works well in a variety of settings and offers several benefits:

  • Beautiful sandstone provides an aesthetically pleasing natural look that cannot be matched by manufactured stone.
  • Sandstone boasts a variety of colours ensuring that there’s a type to suit any location or property.
  • When sandstone is wet, its colour becomes more prominent.
  • Sealed sandstone’s colour does not fade in sunlight unlike manufactured alternatives.
  • A natural stone formed over millions of years, sandstone is a durable material.
  • Despite its strength, sandstone is easy to work with.
  • Riven sandstone isn’t slippery, even when wet.
  • Sandstone is less prone to cracking than many natural and manufactured materials.

What is the correct way to lay sandstone?

Sandstone is a beautiful material but must be laid correctly to create a patio that matches the stunning aesthetics of the stone and one that will stand the test of time. Here’s how to lay a sandstone patio:

  1. Ensure that the site of the patio is level, firm and well-drained.
  2. Mark the area with spray paint.
  3. Dig out the area to a depth of at least 125mm plus the depth of the paving.
  4. Remove all vegetation.
  5. Check that the surface of the finished patio will be at least 150mm below the damp course of the house, if the patio is adjacent to the building.
  6. Use strings to check that the area is level and rake anywhere that requires levelling.
  7. Compact the area with a roller.
  8. Fill the area with at least 50mm of sub-base (aggregate) and then compact the material.
  9. Add a second layer of sub-base (at least 50mm) and compact it.
  10. Ensure that the area falls slightly away from the house to allow for rainwater run-off.
  11. Wash the slabs to remove dust and debris.
  12. Prime the backs of the stone with a proprietary primer or fine mortar slurry.
  13. Create a mortar mix of four parts sand to one part cement and water.
  14. Small area by small area, lay a mortar bed of 50mm.
  15. Lay the stones in the mortar bed 8-10mm apart and tap lightly with a rubber mallet.
  16. Wait 24 hours for the bed to set.
  17. Fill the joints with mortar using a trowel or brush in grout (see below).
  18. Leave the patio to set for at least 24 hours before walking on it.
20230726_074938

What are the most common mistakes when laying sandstone?

Laying a patio is hard work and so it is always tempting to rush or to cut corners. But a lack of attention to detail will guarantee poor results. It is certainly best to use an experienced and skilled contractor to complete the work for you. Always ask to see examples of their previous projects before engaging your contractor as you don’t want to be a victim of bad practices and shoddy workmanship. The most common errors when working with sandstone are as follows:

  • Inadequate drainage - there is no doubt that the most common error when laying sandstone is the failure to ensure that the patio is well-drained. A good contractor will lay the patio correctly and will incorporate drainage channels if they are required. 
  • Wrong size of slab - your contractor should be able to advise you as to the size of slabs that would work well for your space. Small slabs can make small patios feel even smaller while slabs that are too large may not allow you to create your desired layout or pattern.
  • Choosing the wrong colour - always check the colour of slabs when they are wet as sandstone can boast a very different hue when wet and may not deliver the aesthetics you are looking for.
  • Not laying a full mortar bed – a full mortar bed rather than spotting is essential.
  • Laying slabs upside down – some slabs will have a textured side and a smooth side. Laying all slabs textured side up will result in unsecured joints. Laying just some of the slabs upside down will deliver unsecured joints and a less than uniform look.

Should you seal sandstone?

Sandstone is formed over millions of years. it is a durable and weather-resistant material that will not fade or break down quickly. However, it is a porous stone and so will absorb moisture, dirt and other substances that will stain it. 

It isn’t essential to seal sandstone, but sealant will slow down any deterioration to ensure that a patio looks new for longer. Sealant will also prevent staining from spills that can be almost impossible to remove. Both invisible and colour enhancing sealants are available.

How do you maintain a sandstone patio?

All patios require basic maintenance to remain at their best, regardless of their quality and how well they are laid. Without maintenance, a sandstone patio will deteriorate over time. Happily, it is easy to inject new life into your paving.

Whenever you have the time available, it is advisable to treat your patio to a wash. You only need soap, water and a brush to spruce up your slabs. The colour and texture of patio paving will be impacted by dirt, foot traffic and the adjacent planting. That grime can be removed by brushing the stones with soapy water or diluted white bleach.

If mosses, algae (green) or lichens (black or white spots) have impacted your patio, a little elbow grease will be required to remove them. But it is best to avoid using chemical treatments such as fungicides speed up the process as these chemicals may discolour the sandstone.

Do not jet wash your patio on a high power setting unless the paving boasts resin grouting as power washing may destroy the grout and erode the stone.

In addition to regular cleaning, a sealed sandstone patio should be resealed every 1-2 years. Any cracked mortar should be repaired as soon as possible.

What patterns can you create with sandstone?

With a sandstone patio, it is possible to create a variety of different patterns with the slabs. If you are thinking about a new patio, it is worth considering the various options which include both random and uniform looks. The nature of your property could be the deciding factor in your choice of patterns. 

Running bond (rectangular slabs)

A two-course running bond features rectangular slabs of the same size laid in a pattern like brickwork where the joints in every other course (row) match up. It is also possible to create a three-course running bond using slabs of different sizes where the joints in every third course match up. This creates a slightly less formal feel. Running bonds give you neat, uniform looks that are best suited to modern properties.

Running bond (square slabs)

That little bit different, a running bond created with square slabs also provides a formal feel suitable for modern properties. This pattern can be too busy for smaller patios unless large slabs are utilised.

Stack bond

The stack bond layout is the pattern where the joints of each row line up like squares on a chess board. This pattern delivers a classic feel and can suit smaller gardens.

Random patterns

Natural sandstone slabs are available in a variety of sizes and shades, enabling you to evolve more random patterns. These boast an informal look that can perfectly suit older properties such as country cottages. You could utilise a random pattern in each course or repeat a sequence of slabs several times along each course. Courses can be alternated but you could create a patio with an entirely random pattern. Project packs featuring a mixture of slab sizes are available.

How should you edge a sandstone patio?

Carefully chosen edging will perfectly complete your patio. You have many options and the right one will depend on the nature of your property, the position of your patio and the level of formality you are looking to achieve.

Cobble sett edging

Giving you a relatively informal look but a defined boundary, cobble setts complement sandstone and are visually appealing. They can be laid to the same height as the patio which can make mowing your lawn easier if it is adjacent to your paved area.

Bricks

Available in diverse colours, bricks are relatively inexpensive options and can create a pleasing, long-lasting patio border.

Kerbstones

Providing a raised border, kerbstones are practical and pleasing choices that create a clean edge to your patio and that structure your outside space. Usually positioned to edge driveways, these stones don’t cost the earth and are best suited to modern properties. A raised edge to your patio will prevent the soil in adjacent beds from migrating to your patio.

Wood

Weather-resistant wood such as cedar will provide you with attractive and informal edging as would railway sleepers. However, wood is only a practical solution for patios with straights edges.

Bullnose edging 

The beautifully finished and curved edges of bullnose stones create a refined, and formal look with a luxurious feel. Choose from a variety of stones for a matching or contrasting aesthetic. Bullnose stones are more costly that cobble setts, kerbstones or brick.

Retaining wall

A raised patio will require a retaining wall for stability. That wall will give you a pleasing edging for your patio and could be built from a variety of bricks or stones. Dwarf walls are great alternatives to  edging stones or wood as they define the paved area and can incorporate seating or raised beds.

Should you choose a sandstone patio?

There are many good reasons to choose sandstone for your patio. This stunning, versatile and durable material enables you to choose from diverse colours, textures and sizes of slab. Sandstone can be used to design a formal or informal patio that is large, small, uniform, freeform or raised. The possibilities are endless with beautiful sandstone.

by:

Leave a Reply

Your email address will not be published. Required fields are marked *