Table of Contents
Step 1 – Decide which laying method best suits your project
There are two different methods to choose from when laying granite setts, a rigid system and a flexible system. A rigid system involves laying the setts into cement, whereas a flexible system involves laying the setts into sand.
When making your decision, you will need to consider a number of factors including the frequency and type of use, budget and time restrictions and the size of the project.
The flexible system
This method of laying granite setts is cheaper and quicker but should only be considered for lighter traffic areas such as pathways and landscaping. It would not be suitable for driveways as the repeated passage of the wheels of vehicles on setts laid in sand can cause ruts. Therefore, we would always recommend using the rigid system for driveways. And even when using the flexible system on a pathway, you will need to bear in mind that setts laid in sand may move slightly over time and could possibly need some attention. Depending on the nature of your project, you may want to consider cementing the setts around the perimeter to prevent them from moving.
The rigid system
This method is recommended for heavier traffic areas, particularly driveways as explained above. Providing you prepare the ground adequately and have a well-laid sub-base, the only maintenance your project should ever need is the occasional cleaning with a hose pipe or jet wash.
Step 2 – Choose your laying pattern
There are a plethora of patterns you could use, ranging from one of the traditional styles laid in rows, to all sorts of intricate patterns of circles, swirls, shells, fans and the like. You may also choose to use a mixture of different sizes and colours of setts for variety and effect, especially if you choose to lay your setts in a random design. Of course, if you are laying the setts yourself as a novice, you may want to opt for a more traditional method!
Whichever pattern you choose, it’s important to realise that unlike sawn setts which are perfectly cut by machine, natural split or tumbled granite setts which are manually cut, can only be laid with a gap or mortar joint between them. The uneven characteristic of these setts, which gives them their unique and rustic charm, will allow you to place them close to each other, but not actually touching.
We recommend using a gap, or mortar joint of 12-13mm, which will showcase each unique piece and give you the most aesthetically pleasing overall appearance.
Step 3 – Decide how you will joint the setts
Here you have several options and it will depend on whether you are using the flexible or rigid system. For the flexible method, you may choose to brush in jointing sand. For the rigid method, you might decide a dry mix of sand and cement mixture is more suitable.
Depending on budget, time available and the overall desired appearance, there are many other options to consider including wet mortar pointing, bitumen, resin and grouting.
Step 4 – Make sure you have all the necessary materials & equipment
Before beginning your project, it’s essential to have all the necessary materials and equipment.
(Please read our section Before buying your products… under Important information to read before beginning your project at the end of this article).
We recommend the following to make sure you get the job done as quickly and efficiently as possible:
- Protective Gloves
- Knee pads
- Spirit level
- Hammer & Chisel
- String or a straight piece of wood
- Rubber mallet
- Whacker plate or roller
- Tape measure/ruler
- Spray paint (optional)
- MOT Type 1 sub-base
- Pointing tool or Injection gun
For the flexible system
- Bedding layer, 50-100mm of sharp sand to cover the area
For the rigid system
- Sharp sand and cement
- A mixer to make the mortar
Step 5 – Prepare the ground
Whether you’ve decided that the rigid system or the flexible system suits your project best, you will need to thoroughly prepare the ground first. Depending on the size and nature of your project, you may find it helpful to begin by marking the area with spray paint.
(Please be sure to read the section Before you start digging under Important information to read before beginning your project at the end of this article).
Dig out the area making sure you remove all topsoil and the roots of any weeds or plants. To determine the depth you need to dig out, you will need to calculate the depth of your sub-base, bedding layer and the depth of your granite setts. You may want to use a thicker sub-base for heavy traffic areas such as driveways, or if you are replacing an area that was previously a lawn or a soft soil area. A thicker sub-base will give extra stability and prevent any movement in the future.
You also need to bear in mind that if the setts are going to be laid up to your house or other building, they will need to be at least 150mm below the damp proof course once installed.
Another very important consideration is drainage. Requirements will vary from one project to another, and we advise that you thoroughly research what is needed for your particular project. Full details and current legislation can be found on the following GOV.UK website page; https://www.gov.uk/government/publications/permeable-surfacing-of-front-gardens-guidance
If in any doubt, always seek the advice of a professional.
Before going on to lay your sub-base, make sure the ground is completely level. This can be achieved using string lines and a rake. Complete your preparations by compacting with a whacker plate or roller.
Step 6 – Lay your sub-base
It might not be absolutely necessary to lay a sub-base for every project, but it will probably be needed for most. A well laid sub-base will give your granite setts the foundations they need to last for generations.
The depth needed will vary slightly depending on the size and use of your project. For heavy traffic areas such as driveways, you would usually lay around 150mm of MOT Type 1. For lighter traffic areas such as paths and patios, 100mm should suffice.
Compact well before applying the bedding layer, ensuring there are slight falls for drainage. You may choose to lay a concrete base on top of the sub-base first if you are using the rigid system for a heavy traffic area, which should be approximately 50-100mm depending on the nature of your project.
Step 7 – Lay your bedding layer
If using the flexible system, lay 50-100mm of sharp sand on top of the sub-base. Don’t use ordinary building sand or plastering sand as they are too soft and won’t support the setts, which is the whole purpose of the bedding layer.
For a rigid system, make a mortar mix with sharp sand and cement to a wet, stiff consistency without it being too dry, so that it will adequately hold the setts in place. As with the flexible system, building sand or plastering sand isn’t recommended.
Whether you are using the flexible or rigid system, use your thickest stone to work out a more accurate calculation of the depth of the bedding layer needed. You will need the bedding layer to compensate for the different thicknesses inevitably present in natural split or tumbled setts, helping you achieve a more level finish.
Step 8 – Lay your granite setts
Whichever system or laying pattern you have chosen, each sett will need to be carefully selected, positioned and set at just the right level, ensuring cambers are correct to allow adequate drainage.
If using a more traditional pattern with the setts laid in rows, taught string or a piece of wood should be used to maintain straight lines. Laying one row, and up to 1m at a time, place the setts along a builder’s line. Each sett needs to be knocked firmly into place using a rubber mallet, continually checking straightness and height. Be sure to place the setts evenly apart, approximately 12-13mm. Tip: Using a finger width instead of a tape measure or ruler can make measuring easier!
If you are cementing your setts in, keep a damp cloth handy to wipe off any excess that gets on to the face of your setts as you go along.
If you are using the flexible system, depending on the nature of your project, you may want to consider cementing the setts around the perimeter for extra security against movement.
Allow to dry before jointing. Depending on the weather, cement usually takes around 24-48 hours to be dry enough to walk or drive on. If it’s wet and cold, leave as long as possible. And bear in mind that cement only reaches its full effective strength after about 4 weeks, so it’s advisable to restrict using your new surface as much as possible until then.
Step 9 – Complete by jointing
If you are using the flexible system, the traditional method is to use jointing sand to fill in the gaps. As the setts have been laid in sand and no drying time is required, you can actually brush this in as you lay the setts if you prefer. If needed, water in to prevent any movement. You might then choose to also brush in some finer sand or granite dust.
For the rigid system, a popular method is to use a 4:1 dry mix of sand and cement. It is spread across the laid setts, brushed into the gaps and carefully compacted down with a trowel or similar tool. This process is continued until all joints are tightly packed. Be sure to check the weather forecast before starting with this method, whilst it is ok to add a slight spray of water to the mix if needed, it’s not a job to be done in the rain. Finish off by making sure the face of the setts are thoroughly swept to avoid any stains.
As mentioned in step 3 above, there are also lots of other options to choose from including wet mortar pointing, bitumen, resin and grouting. It really depends on the overall final aesthetic you want to achieve, in addition to your budget and patience!
Step 10 – Put the kettle on, sit back, relax and enjoy!
We hope your finished project looks every bit as fantastic as you imagined, and that you are pleased with a job well done!
Important information to read before beginning your project
Before you start digging…
Before beginning any project which involves digging, it is imperative that you complete a full and thorough assessment of the ground in advance. Depending on your project, this may need a professional survey.
Essential factors that need to be checked include subsidence, ground stability and underground pipelines and cables such as electricity, gas, high pressure fuel/oil, heating, water and fibre optic networks, that could potentially be hit, causing damage or personal injury.
You can obtain a free utility asset map for your property, and find lots of useful information and advice by visiting LSBUD, the national safe digging service at https://lsbud.co.uk/
Before buying your products…
Check that all your products are suitable for use with natural stone. Certain chemicals used in some products can react with the natural iron present in granite and can cause oxidisation which looks like rust. There are lots of products available on the market to fix this, but of course, prevention is better than cure.
Continue protecting your granite setts…
Beware of products and items that could potentially cause rust or oxidisation. Certain lawn fertilizers and weed killers contain chemicals which can react with natural granite and cause rust, so always be careful not to spill any on your setts.
Metal items such as barbeques and garden furniture can also cause rust stains, so be sure to store them away in the winter or bad weather.