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Complete Guide to Garden Paving
In this post I’m going to show you how to choose, install and maintain garden paving.
In fact I have been in this game for 15 years now and installed hundreds of patios for my clients. I have noticed that the biggest challenge is right at the beginning - what paving slabs to choose?
Don’t worry, in this guide I will help you understand:
When it comes to patio slabs types, we can highlight two categories. Man-made and natural stone slabs. At first when you are just starting your journey with paving, you may think there are very similar. And actually you’d be right. Visually they are - but only when new.
Man-made paving
Man-made paving can be split into two groups. Coloured concrete and porcelain paving.
Concrete paving - how is it made?
Generally a concrete is mixed with dyes to achieve desired colour and then is placed into moulds that often replicate natural stone appearance. The designs can be endless. From riven surface, so they look like quarried natural stone to polished and perfectly smooth.
Because concrete slabs are manufactured, we get a huge range of colours. Budget slabs may have a single colour like buff, grey or charcoal but the more expensive can have mixture of colours to mimic more natural appearance.
I’m sure you’ve seen a garden stepping stones that look like a log or animal foot shape. These were definitely concrete slabs.
Pros:
- Huge range of colours
- Vast shape variations - might be helpful when looking for something specific like curved slabs or round timber logs shape.
- Good choice of textures
- Some very cheap concrete slabs may not look appealing but are perfect to use for garden shed base. The regular size and thickness makes the installation easier.
- Good quality concrete paving will last long time - specially when they’re properly maintained.
Cons:
- Coloured paving slabs have added pigments which will fade over time. Most concrete paving will loose it’s original colour within first 5-7 years.
- If chipped or cracked, the aggregate is exposed and slab must be replaced. Usually new slab looks very different and stand out of the rest.
- Must be continuously sealed to look good
Porcelain paving
How a porcelain paving is made
Porcelain is manufactured from a blend of high quality clays, quartzitic sands and other minerals such as granite which are then baked in a high-temperature kiln.
There is a lot of preparation required before the unbaked 'biscuit' can be sent into the kiln, and then there's a fair bit of post-firing work required to ensure that what is sent out to the trade is of a sufficient quality and standard.
All porcelain manufacturers are using the same procedure but the ingredients and quantities may differ.First all aggregates are mixed together and are dried with hot to reduce moisture level to just under 8%.
Then blended powder is pressed into moulds and dried again. Now the moisture content is only around 1%.Once pressed, the porcelain tiles will receive it’s final pattern and texture. These are printed onto the surface. Porcelain tile can have appearance of granite, travertine, sandstone or even timber planks.
The final step is firing. Tiles progress through the kiln with temperature reaching 1,200°C then is gradually cooled.
To summarise porcelain slabs:
Pros:
- Extremely durable and low-maintenance, each paver is built to last. They require very little upkeep and have the ability to retain their vibrancy and unblemished finish for years
- Resistant to stains and fading.
- Endless possibilities of appearance and textures
- Frost resistant
- Very accurate sizing. Usually the tolerance is less than 1mm
Cons:
- Can be expensive. Prices starts from £40 / m2 right up to over £120
- Requires specialist cutting blades
- Not for DIY-er. Porcelain does not forgive mistakes. Installer must have a good knowledge about porcelain and be perfectionist. Incorrect installation can lead to expensive repairs.
Natural stone paving
Natural stone paving has been popular for hundreds of years but the recent decades has seen a massive increase in demand. To meet increasing demand, paving stone had to be imported from India, Brazil, China or Egypt.
With growing amount of suppliers, natural stone became cheaper and more households could afford to have natural looking patio.
Indian Sandstone
Indian Sandstone has become the most popular imported stone. It comes in variety of different shades and colours. From greys, browns, greens to golden, orange and reds. It’s important to note that some suppliers offer cheaper prices but their paving slabs are not colour sorted.
For example Fossil Mint Sandstone has variation range of colours from orange through yellow to white. When installed in random pattern this stone would look like a patchwork.
Good supplier should have all the paving sorted by colour tone.
Another point to note is that not all sandstones are equal. The main difference is porosity.
Porosity is simply a void within the stone. The more voids in the stone the more porous it is. More porous means more water absorption. During the hot summer days this may not be a huge problem because water absorbed by paving will quickly evaporate. Problems will start during the colder months, when patio is soaked for weeks. These are perfect conditions for algae growth. Newly installed patio will look awful and very tired after only first few colder weeks.
You probably asking yourself - “yeah, so how do I know which sandstone is good?”
Ok, so porous stone is a lot softer. You can try to crumble the corner with your fingers. If it breaks, don’t buy it.
You can pour some water on the stone. If it soaks in like a sponge, don’t buy it.
Also light coloured paving tend to be more porous.
Low price might be tempting but generally speaking you get what you pay for.
Pros:
- Available in wide range of colours and sizes
- Most of good suppliers provide calibrated paving. It means that the thickness of a patio slabs is consistent throughout the pack. This speeds up installation time and reduces the costs.
- Sandstone is often supplied with riven edges which gives a natural look.
- Being very popular is also widely available “off the shelf” at competitive price. Sandstone can be bought from as low as £20/m2
Cons:
- All sandstones are porous and require maintenance.
- Some poor quality pavers will age very quickly.
- Stains very easily and are hard to clean.
- Not recommended for driveways. Specially light coloured paving.
Limestone Paving
Limestone is another very popular patio stone in the UK. The colour palette is perhaps not as wide as Sandstone but it comes in very dark colours instead. Limestone is consistent in colour and comes in some select colour choices, usually buff-grey, blue-grey and blue-black.
In general, limestone is defined as being composed of calcium carbonate. Calcium carbonate often comes from plant and animal skeletons and remnants including the shells of mollusks.
Limestone is consistent in colour and texture and is considered as hard wearing stone.
It’s usually supplied with straight edges as opposed to riven of sandstone.
Limestone has become very popular in the recent years thanks to it’s dark colour. We have noticed a trend for contrastic colours in recent garden designs. Many garden projects features dark floor with white walls or vice versa.
However there is one thing that many paving suppliers will not tell you.
Limestone fades really quickly when exposed to UV rays. I mean it becomes chalky in just few weeks. Suddenly the contrast you had between patio and wall disappears.
To prevent this, limestone must be sealed as soon as possible. The sealing process may need to be repeated every year, depending what product was used.
Very important advice to remember: NEVER use acid based cleaning products on Limestone.
Pros:
- Pretty good hard wearing stone
- Consistent in colour and texture
- Contemporary look
- Low cost - prices very similar to Sandstone.
- Readily available
- Easy to work with.
Cons:
- Similar to Sandstone, Limestone is porous and will absorb water
- If not sealed, it will stains very easily .
- Limestone will become chalky within few weeks of installation if not sealed properly.
Slate paving
Slate paving is considered to be a premium quality paving. Slates are very dense with very low porosity. Slate stone has been used in building industry for decades. Mainly in roofing industry. As the importing became easier, we have started to see more slates being used as a paving material.
Slate paving has a sleek appearance with rich colours. Available in dark blue, green and rustic tones.
Like all other paving, slates can be supplied calibrated but due to a layered structure of that stone, you are likely to may more for calibration.
Slate does not have to be sealed and it holds the colour for years. General maintenance like occasional jet-wash is all that’s needed.
Good quality slate paving can be compared with porcelain in terms of durability and it’s also in the same price range as porcelain tiles.
Although the slate patio installation can be expansive, it’s always seen as an investment.
To summarise Slate slabs:
Pros:
- Beautiful rich colours and standout texture
- Colour will not fade
- Requires minimal maintenance
- Very dense structure and low water absorption
- Easy to clean
Cons:
- Can be difficult to install if you buy non calibrated slate
- Sometimes a layer of slate can flake off and create water pit.
- Good quality slate can be expensive
Granite Paving
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 is incredibly hard nature.
This makes granite paving very unique and different to the others. It’s very durable and hardwearing stone. Granite comes in wide range of colours and textures.
The make-up of granite can be any from 65%-90% feldspar and 10%-60% quartz. As you can see, there is quite a variation in make-up so the result as a variety of colours and finishes.
Granite has the lowest porosity of all natural paving stones available in the UK market. Good quality granite has water absorption rate of 0.2%. It means water can’t penetrate through the stone.
However, like with any other products, we have noticed quality variations. I have come across some cheap granite which was very porous and required a lot of work to keep it clean. What’s worse is if you get poor quality granite in light colour, you will see patches of moisture being drawn from the ground below. Sealing the stone on all sides can be solution but unfortunately, this problem is usually noticed after installation.
To summarise Granite Paving:
Pros:
- Very durable stone
- Available in wide selection of colours. From white, silver, grey, yellow, pink to dark blue and deep black.
- Good choice of surface finishes. They can be natural split, sandblasted, flamed, sawn or honed
- Very low porosity
- Requires minimal maintenance
Cons:
- Can be hard to work with. Granite is a heavy stone and difficult to cut.
- Can be expensive
Now you know what paving slabs are available in UK market and you know the difference between them but I wouldn’t be surprised if you’re still confused which paving is right for you.
When I design a garden patio, I always start with colour.
In most gardens, the majority of colours comes from natural elements. Planting is mostly green and materials are made from stone that has subtle shades of beige, greys and so on. In addition, the colour of these elements is not pure but a diverse mixture of different colours that change under weather conditions and seasons.
In the garden, materials comes from far and wide and sometimes we have a problematic compositions, mostly because they have been introduced by men rather than nature.
It’s not guaranteed that putting any one object with any other in terms of colour will always work.
There are different models for explaining colour, but the simplest and most relevant is the RGB.
RGB stands for Red, Green, Blue colour system. RGB is the way the human eye sees colour. RGB means that all colours are made by mixing any two colours of red, green and blue.
Based on our natural understanding of colour we often divide colour into groups of warm and cool colours.
We describe colours as ‘cool’ or ‘warm’ because in nature, this is literally how colours represent differences in heat, for example fire and frost.
In nature we can find three colour schemes.
Harmonious
Harmony comes from colours that are close to each other on the colour wheel. For example Red - Orange, Blue - Green
Complementary colours
Complementary colours are those opposite each other on the colour wheel
Triad colour scheme
Triad colour scheme is a group of three colour and are related by opposing triangles.
Now that you know how to compose the the colours together, you just need to look around your garden and choose the right scheme colour.
This colour model is used by designers in all industries. Interior, exterior, cars, bikes and so on.
When you know the colour of your paving, it’s time to choose the stone type.
Choosing the stone type for your patio is determined mainly by the usage and colour.
If you plan to drive a car on your paving, consider hard wearing stone in darker tones.
Most paving can be used on driveways when correctly installed but the stone that is porous like sandstone might not be as practical.
BBQ areas tend to be a bit messy when in use. Some grease or wine can be spilled on the floor so you should consider a surface that is easy to clean like porcelain or granite.
Another factor to consider when choosing a stone type is a style of your garden.
If it’s a cottage you want a stone that looks as natural as possible. This means uneven surface, riven edges. A stone with it’s natural imperfections.
If you are in modern urban garden, you can choose sleek slate that will contrast with surrounding walls or fences. Porcelain or granite can also be a good choice.
Sometimes the most important factor is the price and if we can’t afford Brazilian Slate but would love to have dark coloured patio, choose Limestone. You have to remember to seal your paving to keep the colour.
My advice is to never compromise on stone quality. Unless you make a base for shed.
Sooner or later you will regret if you purchase low quality paving. If you can’t afford it now it’s always better to wait, save up and buy a good product. Patio installation is not cheap but if designed and installed correctly it can be a great investment in your property.
Before any ground is broken, draw a plan of works. You don’t need any drawing skills to plan a patio.
A good site layout is very useful along with materials list.
When a patio touches any buildings, first thing to look for is a damp proof course of that building.
On older buildings this was a layer of slate. Now black membrane is used to prevent damp raising up the wall.
Why is this important?
Basically if a patio is build less than 10 - 15cm below DPC, rain will splash above DPC and it will create damp problems inside the property. I have seen paving installed very close or even above DPC with a massive damp patches on interior walls.
Once you found damp proof course mark a line 15cm below. This very important - do not lay paving slabs above this line.
Next, think where rain water will go. Ideally patio should slope away from the house. Rain water would then go into the ground. Unfortunately on most occasions that’s not possible. Simply because lawn is often higher then patio. In that case if you slope towards the house, make sure to install drain channels and connect to either a soakaway or rain water drain.
Now that you have planned your levels, it’s time for hard work.
- Dig down 15cm below the finished patio level.
- Lay down a landscape fabric. This will prevent the aggregate from moving over time.
- Prepare a base. This should be 100mm layer of Type 1 subbase. Base must be compacted down with a wacker plate in two stages. So you’d spread 50mm Type 1, compact and then final 50mm on top. 1 bulk bag of Type 1 is sufficient for 4 square meters
- Prepare a mix of sharp sand and cement in 4:1 ratio. Add water and some plasticiser to make mortar more flexible.
- Depending of what paving slabs you’re installing you may have to prepare them prior to laying. If you have non porous paving, like porcelain, granite or slate apply a bonding bridge to underside. This can be SBR mixed with cement and applied by thick brush. If you have porous paving that require sealing, it’s best to seal it prior installation.
- You can now start laying paving slabs. If your slabs are calibrated (all slabs same thickness), you can spread the mortar to required level and start laying the slabs. If your paving are all different thickness you have to spread the mortar for each slab individually.
- Leave at least 24 hours after laying before you start filling the joints.
- You can fill the joints with a semi dry mix of building sand and cement or buy a ready mixed resin based paving grout. Although paving grout is more expensive I will definitely recommend it. It’s very easy to apply, does not stain the paving and speeds up the process by at least 3 times. Your back and knees will appreciate it.
- You did it! Well done.
- Enjoy
How to choose paving grout
If you look at the newly installed patio for the first time and the first thing you notice is grout, it means it’s been badly applied or wrongly chosen.
Not that long ago, say 8 - 10 years ago the option to fill the paving joints was sand and cement. This was tedious job. It took ages to grout a 40 m2 of paving. All carefully done to avoid cement stains on the paving. What was worst is when it rained before cement has set, we had to do it all over again plus clean the patio.
Today we have a bigger choice of paving grouts on the market. The application is a lot easier. With resin based paving grout, all you do is wet the surface, brush the grout in, strike it with pointing tool to give a nice finish and brush the excess off. What’s best, if rains you don’t have to worry because paving grout will not set or stain while wet.
What you have to pay attention to is the strength of grout. For example not all grouts are suitable for driveways and others can only be applied to a certain widths of joint.
Wide range of colours is available to choose. You can have a white, contrastic grout for dark slate or limestone or beige for sandstone. More on how to choose the right colour few chapters up. It’s the same rule as with choosing a paving slabs by colour.
How much patio cost?
The prices will vary throughout the UK but as a general rule you should have a budget of £130 per square meter plus the cost of paving slabs. This is based on normal conditions, which means easy access for a wheelbarrow and the excavation not deeper than 15cm.
How to clean a patio
The simplest and safest way of clean a patio is to scrub it with soapy water and a stiff broom. This could be wash-up liquid or floor cleaning products. As long as is acid free, it’s safe on all types of paving.
If you have outdoor tap, it’s good to equip yourself with power jet wash. It doesn’t have to expensive fancy machine. You can get a basic jet wash for less than £70. By cleaning your patio with power wash every 5-6 weeks, you will never need to worry about using chemicals on your patio.
If your patio needs deeper cleaning and soapy water done nothing, you have to look for better solutions.
On natural stone you can use bleach diluted with water in 1:1 ratio. Spray the solution on paving, scrub it with stiff brush, leave for 30 minutes and rinse with plenty of water.
You must remember that any plants that will come in contact with bleach will die, so make sure you protect them.
Bleach can be used on Granite, Sandstone and Slate.
NEVER use bleach on Limestone and concrete. It will harm your paving potentially forever.
Another way of cleaning your patio is a mix of vinegar and water. Procedure is exactly the same as with bleach. Again, make sure you don’t use it on Limestone and concrete.
Limestone can only be cleaned with non aggressive products. If soapy water didn’t help search for cleaning product that is specific for Limestone. A good tiling store should have one.
Coloured concrete can be tackled with block paving cleaner. Don’t use aggressive acid based cleaners as this will strip the colour of your paving.
As ever, prevention is better than cure. A good practice is to seal your patio after deep cleaning. This will keep your patio in good form
