Photo Credit: Arbor Landscapes
How to Lay Reclaimed Natural Stone Setts: A Complete Guide to Bound Construction
Reclaimed setts are without doubt one of the finest surfaces there is, not only visually but longevity wise too. Many roads laid to setts today are in excess of 150 years old and some are still in pristine condition. Read more about Setts here.
Setts are most commonly Granite, in colours ranging from grey, pink/red or buff. Gritstone or sandstone setts are particularly abundant in Yorkshire and Lancashire. Less common types of setts are the igneous stones Basalt and Dolerite which are sometimes called ‘Whinstone’. Sedimentary limestones setts are often seen around the White Peak in Derbyshire.
Laying reclaimed setts is somewhat of a forgotten art for many, especially with cheap natural stone exported to the UK from all over the world and reclaimed products being slower to lay, much more expensive and relatively difficult to lay in comparison to some materials.
For reclaimed setts to be shown off at their best, the right property and setting is essential. For example, reclaimed setts won’t exactly look in place on a new build estate in North London, in an ultra-modern style.
Setts often come in large loads straight off the back of articulated lorries or are delivered in the ubiquitous bulk bags most commonly used these days. The best-case scenario is to find that the setts have all been salvaged off the same project, for continuity and aesthetics.
As a general rule of thumb 1 ton of 100mm2 cubes will cover 4.5 sq m, large sandstone setts 2.6 sq m and large granite setts 2.7 square meters.
Laying setts in 2025, we would go down a similar route as laying a standard driveway. Setts are often laid to a camber with a cross fall of between 1-60 and 1-80 or a longitudinal fall of 1-50 and a cross fall of 1-80.
SuDS Compliance
Sustainable Drainage System (SuDS) compliance regarding water management is required in the installation of a driveway, ensuring water does not run onto the highway. Aqua cells, which act in a similar way to a soak away, are often used to manage driveway
surface water run-off. Aqua cells should be installed 5m from the property and 2m from a boundary. A minimum B-125 specification channel drain should be used on a driveway.
Consider the laying pattern to be used, such as half bond or 1/3 offset bond or if you’re feeling adventurous Bogun pattern or Florentina patterns. Set out the area to ensure no small cuts of less than 1/3 at the edge of the paved areas. This is not only for aesthetic reasons but also for the structural integrity of the driveway. If small cuts less than a 1/3 the size of the smallest sett cannot be avoided, the ‘inboard’ cutting technique should be employed. Inboard cutting is an installation technique which eliminates small cut pieces at the edge of driveway that are usually structurally weak and in the case of setts can look visually poor – small cuts next to larger cut pieces. This often means making small alterations to the laying pattern, which is why the initial setting out important.
Firstly, locating piped and cable services – such as gas, electric and broadband – and their depth is essential. A CAT scanner and Genny cable detectors are recommended. The white service boxes at the sides of newer properties show where cables and pipes enter the ground: digging carefully beneath them to locate the depth at where the pipe bends is a good indication of their overall depths and their direction.
Inspect manholes with regards to their depths to ensure that sufficient Type 1 base and subsequent courses thereafter can be achieved including bedding mortar and the depth of the setts. The structural condition of manhole chambers should be checked: often on old properties the mortar perishes between the bricks and when compacting around chambers as this can cause damage and collapse.
Consider the weight of the homeowners’ vehicles, such as car, van or even motor home. Vehicles heavier than a standard vehicle will alter the design requirements of a driveways base/foundation: refer to British Standard BS7533:102 clause 5.8.2 for guidance on subgrade analysis and then refer to BS7533:101 for design of the base, subbase and possibly capping layer if required.
The minimum excavation depth is dependent upon the depth of setts to installed, plus a minimum 150mm compacted depth of MOT type 1 and 40mm bedding mortar.
The fall of the formation level should match that of the surface course.
Compact the subgrade.
Best practice would be to install a geosynthetic non-woven membrane to prevent fine particle migration into the subgrade. The geosynthetic membrane should overlap by a minimum of 300mm. Indeed, good practice, especially on poor subgrades would be to install a geogrid/biaxial mesh. Again, geogrid should be overlapped by a minimum of 300mm and suitable zip-ties installed to connect them together.
Best practice is to install edge restraints prior to base and sub-base installation so as to provide sufficient load bearing support and resist lateral force. The edge restraints should be laid to a concrete bed and haunch and should have a vertical face level with or below the bedding mortar/laying course.
Upon delivery of your MOT type 1, a close inspection should be carried out to its moisture content. It should be moist but not saturated. If it is too dry, it will not be lubricated sufficiently and will lack interlocking capacity. If it is too wet, it can lose its load-bearing capacity.
Install MOT type 1 to a minimum, consistent compacted depth of 150mm, at the same fall as the subgrade. The MOT type 1 should be installed in layers no more than 70mm in depth which will compact to approximately 50mm depth. Compaction should consist of 5 passes both horizontally and perpendicular, a good indication that sufficient compaction has been achieved is there will be no lines in the MOT type 1. A forward and reverse diesel compacter, or even better, a ride on roller are the best forms of compaction machinery.
It is also good practice to “dip” the base which is a method of installing to parallel string lines. Usually, the first string line would be 150mm below the damp proof course or the level of the garage floor in some instances, and the second string line placed at the bottom of the driveway level with the pin kerbs of the footpath, pulling the 3rd string line pulled taught at 90 degrees to the baseline level with top of the 2nd string line every 1m to ensure an even distribution of Type 1 with no humps or hollows. Should there be low spots, these can be filled with Type 1 and compacted, high spots may be raked to low spots or levelled. When measuring from the 3rd string line to the MOT type 1 base, consider the depth of setts plus 40mm bedding mortar.
Laying Course – Bedding Mortar
Set out string lines to levels and falls. String lines should have a tingle or intermediate line pin every 6m to prevent line sag.
Bedding mortar should consist of 1-4 Ordinary Portland Cement (OPC) and one of the following aggregates: 2-6mm, 1-4mm or 2-8mm crushed rock. The mortar mix should have sufficient water added to hydrate the cement and form a ball that holds its shape in your hand when compressed with your fingers. A wet or moist mix is more than acceptable, but not a dry mix.
The thickness of a mortar bed should be a minimum of 40mm and maximum 50mm as an approximate guide, mostly depending on the moisture content of your mortar mix. It is important to compress the mortar sufficiently when using your rubber maul to achieve sufficient strength. A moist rather than wet mortar mix is often preferred when laying setts, it is important to hydrate the cement sufficiently.
Mortar in ambient temperatures is workable for approximately 2 hours; after that a new mix is required. It is considered bad practice to keep adding water to rehydrate the mortar as it loses its strength.
There should be no organic matter such as leaves on the type 1 base prior to laying mortar.
Laying the Setts
Gauging the setts is the process of measuring each setts width and depth, sorting them in to their appropriate sized piles, for example granite setts range from 3 inches, 3.5inches, 4inches, 4.5 inches and occasionally 5 inches, although in my experience there never seems to enough 5 inch setts. The setts are then laid in rows of one size so as to achieve consistency, which in turn creates an even joint width which is not only aesthetically pleasing but adds to the structural integrity of the surface.
Assuming a stretcher or running bond is the chosen laying pattern, no bond should be less than 1/3.
I work to a string line that runs across the tops of the setts and a second string line that runs down the middle of the joint between previously laid row of setts, this allows for tolerances to be evenly distributed both top and bottom of each row. The string line should be kept square/parallel to the baseline at all times.
When laying each sett, I’d recommend dipping the bottom of each into a bonding mortar, to ensure a ‘belt and braces’ installation. Spread the bedding mortar out, but only enough to do no more than 5 setts. The setts should be installed horizontally to ensure that the bedding mortar rises up the joint, this is similar to the pick and dip technique some bricklayers use and will provide greater structural integrity. The setts are then compacted with a hand maul to the desired level or 1mm bellow the string line.
Joints should be between 10mm where possible, the reason is you will get a much smoother surface the tighter the joints, superior structural integrity and less jointing material is required. Aesthetics wise the setts are the star of the show not the jointing material.
A long straight board, often a piece of 100mm x 50mm timber is used to run along the top of the setts to achieve an even surface.
Cutting setts will sometimes be necessary, dressing and fettling the cut edge will take your eye away from the straight lines left by a cut off saw.
Jointing the Setts
A proprietary BS7533 compliant slurry grout is by far the best solution to joint setts.
Pitch may also be used that complies with the below, noting that pitch joints are generally 20-25mm wide.
Correct Pitch Grade:
• BS 3690:1989 – Grade 85/40 or 95/25
• These are penetration-grade bitumen’s.
• 85/40 is most commonly used for jointing setts due to its ambient balance between flow and hardness.
What those numbers mean:
• First number (penetration): Indicates softness—lower numbers = harder pitch.
• Second number (softening point in °C): Higher = more heat resistant.
Why 85/40 is preferred:
• It’s soft enough to flow into joints when hot but hard enough once cooled to withstand traffic and weather conditions .
Best practice when installing pitch is to fill the joints with 6-10mm clean crushed rock 25mm from the aris and the hot pitch is poured and fills the voids between crushed rock and then finishes level or just below the aris of the setts. I do have to say my preference is by far a slurry grout with tight joints.
Maintenance
Repair any damage or wear and tear to the driveway immediately, brush the surface regularly so as not to allow detritus to build up and carry out weed maintenance regularly. Light power washing to remove algae and keep the surface clean is recommended.
