Lay a Brick-Bond Patio With Marshalls Fairstone Setts in 9 Steps for a Crisp Pattern

Set the falls first

Mark the drainage before a single sett is bedded. A patio needs a fall of about 1:80, which means one unit of drop for every eighty units of run. On a 4 metre patio, that works out as a 50mm fall from the house wall outward.

Put the levels on string lines fixed to steel pins driven outside the patio footprint, where they can stay in place through the job. Run the high line along the building side and set it roughly two courses of brick below the damp proof course. Drop the far line by the calculated amount, then check the run with a spirit level laid on a straightedge.

Fairstone setts have riven faces and slight thickness variation, so the falls built into the subbase and screed carry the drainage. Cross-falls can help as well. A patio that sheds water toward one low corner, an aco drain or a soakaway is much less likely to pool after rain than a dead-level surface.

Measure the two runs and the diagonal at this stage. Brick bond makes an out-of-square edge visible as a widening gap along the perimeter sett, where the eye usually lands first.

Excavate for the full buildup

The buildup under Fairstone setts is deeper than many first-time installers expect. Allow 100mm to 150mm of compacted MOT Type 1 subbase, a 30mm to 40mm mortar screed, and the sett thickness itself, which sits around 50mm. The total excavation is roughly 200mm below finished surface level, with extra depth on soft ground or clay.

Dig to a steady depth against the string lines, then compact the formation with a wacker plate before the stone goes in. A vibrating plate compactor in the 70kg to 90kg class should cross the formation four to six times, until the surface stops deflecting under the machine.

Any soft area that keeps pumping water and fines needs to be dug out and replaced with more Type 1. The screed is there to bed the setts to level, while the prepared ground below carries the load. Skirting board prep teaches the same lesson indoors: a wall scribed straight saves fighting gaps later. Get the substrate true and the visible layer follows.

Compact the MOT Type 1 in lifts

Tip the Type 1 in 75mm layers and compact each layer separately. Two 75mm lifts compact better than one 150mm dump, because plate energy only travels so far before the lower material stays loose.

Lightly water each layer before compaction so the fines bind and the angular aggregate locks together. The finished subbase should take only a faint footprint and should feel firm, with enough moisture for the fines to hold.

Rake the compacted surface to the falls already set on the strings, checking with the straightedge and level as you go. Leave a consistent 30mm to 40mm gap between the compacted Type 1 and the underside of the setts so the screed has its working depth. If that gap closes to 10mm in places and opens to 60mm in others, the mortar bed will cure unevenly and the surface can show the mismatch within a season.

Pull a screed batten across two timber rails set to the falls before mixing mortar. This confirms that the base profile is parallel to the finished level.

Mix and place the bedding screed

Use a 4:1 sharp sand to cement screed, mixed semi-dry, with only enough water for a squeezed handful to hold its shape without slumping. This bedding screed should be mixed in batches you can lay within about forty minutes. Once cement begins its initial set, the mortar loses grab and the setts stop keying into it properly.

Lay the screed in a band wide enough for two or three rows of setts at a time. Screed it to the falls with a notched batten. Use a full-bed method, where every sett sits on continuous mortar with no voids underneath, which prevents the rocking and sinking associated with spot-bedding under foot traffic.

Slurry priming improves adhesion. Brush a wet cement slurry, sometimes sold as an SBR-modified bond bridge, onto the back of each sett before bedding. That gives a chemical grip between the riven underside and the screed. Setts laid dry onto a dry screed can lift loose within a year because the two faces have no bond.

Work off boards laid on the screeded area so your weight does not deform the bed. Tap each sett down with a rubber mallet to the string line, then check across three or four setts with a short spirit level. A sett sitting 2mm proud creates a shadow line across the whole bond once the surface dries.

Keep the brick bond on its half-sett offset

Brick bond, or stretcher bond, depends on a repeatable half-sett offset. With a 100mm sett, the offset is 50mm. Small errors stack quickly across a patio, which is why the first two rows matter.

Start the first row from the squarest edge, usually the house wall. Snap a chalk line before bedding to confirm that the row is straight. The second row begins with a half sett, or with the joint centred on the first sett below it, depending on whether the edge detail uses a cut at the side or a running half.

Hold the joint width at 8mm to 10mm. Spacer pegs or a cut timber gauge give a steadier result than eyesight alone. As the day goes on, tired hands tend to open joints, and the pattern slowly widens.

Lay a long straightedge along the joint lines every four or five rows. A 3mm cumulative drift shows as a visible curve in a perpendicular joint that should read straight. Once that curve appears, the repair is lifting the affected setts and relaying them to the line.

The face variation in Fairstone can tempt small adjustments, especially where one riven top sits a little higher than its neighbour. Treat the bond measurement as separate from the surface texture. You have three separate references doing three separate jobs here: the string line sets height, the gauge fixes spacing, and the chalk line holds direction. Mixing those up is how the offset wanders.

Keep checking the half-offset across the field, particularly after stopping for a mix or moving boards. The bond stays neat because you take the same small measurement again and again as you go.

Cut the perimeter from the actual opening

Where the pattern meets a perimeter, cut the setts with an angle grinder fitted with a diamond blade. Mark each cut against the actual gap, since the perimeter is rarely perfectly parallel to the bond lines.

Reserve cut setts for the edges and keep full setts through the field. That keeps the rhythm of the brick bond intact across the main surface, while the perimeter absorbs the small changes needed to meet walls, kerbs or edging.

Give the bed time to cure

Leave the bedded setts untouched for 24 to 48 hours before jointing, with more time in cold weather below 5C because cement hydrates slowly. Walking on a green bed can push setts out of level and shift the pattern you have just set.

Joint the 8mm to 10mm gaps

An 8mm to 10mm joint suits a brush-in resin jointing compound or a dry mortar slurry. Resin compounds such as those sold under the Marshalls Weatherpoint or GftK ranges go in damp. Brush the compound across the surface, consolidate it into the joint with a pointing tool, then sweep residue away before it cures on the riven face.

Riven Fairstone holds compound in its texture, so clean the surface faces quickly and thoroughly. Residue left in the high and low points of the face can harden before the joint below has been fully finished.

For a traditional finish, use a wet mortar point at 3:1 sand to cement. Press it in with an iron and strike it slightly recessed. That profile suits the stone, sheds water away from the joint shoulder and lets each riven sett read individually.

Work in shade or on a dull day. Direct sun flashes surface moisture away, the compound skins before it consolidates, and cracks can appear at the shoulder within weeks. Keep foot traffic off until the jointing has fully cured, which can mean 24 hours for resin systems and closer to three days for cement mortar.

Read the edge lines

Stand at the corner where two perimeter rows meet and look down the joint lines in both directions. If the half-bond offset has held, every alternate joint lines up across the whole field and the cut setts at the edge sit at a consistent width.

A 50mm offset that has crept to 40mm by the far wall throws every cut sett out, and the perimeter is exactly where that error is hardest to hide. The question worth carrying into the next job is whether you can catch the drift before the field is fully bedded, while the affected setts can still be lifted and relaid without disturbing the rest.