Natural Stone Paving – Five Top Tips
Paving Products Top Tips Natural Stone

Natural Stone Paving – Five Top Tips

July 29th 2022

Installed correctly, natural stone is a fantastically versatile paving option, oozing with character and practicality.

The below Top Tips are to help educate you on best practices which ensure a superb looking patio that you can appreciate and enjoy for years.

Allow For Cuts, Breaks And Waste

When measuring and ordering stone for your project, be sure to factor in an additional 10% of paving to allow for cuts and breakages. It helps the project run smoothly and avoids additional costs down the line should you run out of paving.

More often than not, a project will involve the need to cut flags to shape as every patio is unique. The off cut may not be usable elsewhere in the project, so becomes wastage.

Similarly, although it is very strong, stone can still break whether that be during the transportation or on-site - it is almost inevitable.

Ordering an extra 10% is common industry practice; it alleviates falling short and holding up the project and allows a contingency to select and lay the best stones and use any chipped or less-desirably coloured flags as cuts.

Always Lay On A Full Mortar Bed, Never Spots!

It is essential for your paving to be laid on full mortar beds and never ‘spots’ or ‘dabs’, for three very important reasons.

The main reason, and one which becomes the most glaringly obvious, is the unsightly marks that show up across incorrectly installed paving. When a porous stone is laid on ‘spots’ or ‘dot and dabbed’, the moisture transfers through the mortar into the stone, but not where the space is between the mortar – leaving an ugly domino-resembling pattern across the paving. This is known a reflective staining – gaining its name from the marks being a ‘reflection’ of the mortar bed.

Aside from ruining the aesthetics, paving laid on spots is less sturdy than on a correctly laid full bed. Not only are the flags more likely to work loose, but the voids create weak points across the patio which can be more prone to damage – particular if something heavy is dropped.

The voids left between the mortar spots will also cause issues when it comes to the pointing between the paving. Not only will much of the jointing compound or jointing mortar be lost between the voids, but over time the pointing is more likely to fail as it is not supported in place by the full mortar bed.

Blend Batches

Sandstones develop their characteristic colours from deposits of sand and sediment which settled millions of years ago. The natural minerals and make up of these deposits are what result in the variety of colours and shades which gives the product such wonderful character.

When quarrying, new shades of stone are revealed as the extraction progresses. This is why sandstone can sometimes be more of one colour in one pack and less so in another as the batch of stone quarried progresses – nature decides!

For this reason, it is very important when laying stone, to work from all of the packs available for your project, in order to mix any potential batch variation together.

Failure to do so can result in a ‘patchwork’ effect, where the stark contrast of one batch is highlighted alongside the next.

Here, the original patio (left) has been extended with more of the same stone. However, this new batch has more red tones than the original batch which exaggerates the difference. If the entire area was laid at the same time, working from both batches/crates would have allowed the colours to be blended together, avoiding any noticeable differences.

Maintaining Your Paving – Do Not Use Acids!

Simply put, acidic products can permanently stain your paving and should be avoided at all costs, but many people don’t realise and fall foul to this mistake - only realising once its too late.

When it comes to maintaining your patio, there are many simple, inexpensive solutions to keeping your paving looking great without the risk of ruining it.

A simple soap and water solution and a good scrub is often enough for light dirt and debris. If your stone has weathered a bit more, a jet wash can make light work of surface dirt – but be sure not to get too close and blast out the jointing!

For more troublesome marks and stains, there are many suitable cleaning products designed specifically for natural stone. There are products which target organic matter such as algae and lichen; cleaners for rust, solutions for salt and deep cleaners to tackle tougher stains.

Maintaining natural stone isn’t difficult when you use the right products for the right job. But just remember, that product is NEVER acid!

Consider Your Ancillaries

When planning and installing your paving, there are some additional products that we offer to help enhance and improve your project which we think are really worth considering.

The first, is using a bond bridge, also known as priming slurry, slurry coat or primer. This is a cementitious based product which provides superb adhesion and helps to create a barrier against staining.

The priming slurry is simply brushed or trowelled on to the underside of your paving right before the piece is being placed on to the mortar bed. It sets quite quickly, and when it does, it forms a super-strong bond to the mortar bed.

Another fantastic benefit priming slurry offers, is that by creating a barrier between the mortar bed and the flag, it significantly reduces the amount of staining caused from moisture being drawn through the mortar and on to the surface of the paving such as efflorescence.

Priming slurry is essential for impermeable paving such as porcelain and slate but has become increasingly more popular and recommended by experts for use on sandstone and limestone. It is inexpensive, requires little additional effort and offers some genuinely great advantages.

Another element of your project to consider is how it will be jointed. For Indian stone paving, the traditional choice has been sand and cement mortar pointed by hand, but nowadays, the most popular option is jointing compounds which are incredibly easy to use, save hours of labour and provide a professional quality finish.

Simply soak the patio, pour out the contents and brush it in to the joints. The key is to keep the area wet to help it flow in to the joints and keep the resins off the surface. For these reasons, jointing compounds can even be applied in the rain! Jointing compound sets solid once the water has drained away. For this reason, it is recommended to used a 5:1 or 6:1 mix for your bedding mortar which offers some porosity. Stronger mixes or installations on top of a concrete slab are not recommended, so is worth bearing in mind when planning your install.

Flowable grouts (also known as jointing mortars) are also becoming more popular due to the strengths and finish they achieve; however they are better left to the landscapers to install as these products require speed, accuracy and bravery…

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