7 Step Brick Patio Repointing Method with Geofix Jointing Compound Over a 12-Metre Run

A 12-metre brick run typically carries between 480 and 660 individual joints once both bed and head joints in a herringbone pattern are counted. Geofix, sold by Everbuild in 14kg tubs, covers around 4 to 5 square metres of joint at a 15mm depth per tub on standard 50mm-wide block paving. Two tubs handle most 12-metre patios laid at standard widths. The compound is a kiln-dried sand and polymer blend that cures on contact with moisture, so the order of work is simple: dry joints for filling, damp joints for curing.

Why the joints fail before the bricks do

Water sits behind almost every failed patio joint. Rain enters a hairline crack in old cement pointing, freezes, expands by about 9 percent, and widens the crack with each cycle until, after three or four winters, the pointing crumbles to grit and the bricks begin to rock.

Weeds arrive after that. A 2mm gap holds enough windblown soil for moss and meadow grass to root.

Geofix deals with that movement by curing with a slight flexibility. A sand-cement mix can split along a rigid line when the slab below shifts with ground temperature, while the polymer binder in Geofix resists the freeze-thaw expansion that breaks traditional pointing. That is why wet mortar has lost ground to polymer jointing compounds on a large share of domestic block-paving jobs over the past decade.

Steps one and two: clear and gauge the joints

Rake out every old joint to a minimum depth of 15mm. A standard joint-raking tool with a tungsten tip works on cement, and a flat-blade screwdriver with a stiff wire brush will usually clear softer, failed pointing. Depth is the part to check repeatedly. Geofix needs a 15mm bed to hold, because a shallow fill at 5mm or 6mm can peel out in sheets within a season.

Gauge the width as you clear. Geofix performs in joints from 3mm to 50mm. Joints below 3mm will struggle to accept the grain of the kiln-dried sand, so leave those tight joints alone or widen them with an angle grinder fitted with a 3mm diamond blade.

For tub count, measure a representative metre, count the joints in that strip, and multiply across the 12-metre run. Brick pavers laid on edge in a herringbone bond sit high on joint count, so an extra tub is a sensible allowance for this kind of run.

Step three: the patio must be bone dry

Geofix cures on moisture. Damp joints activate the compound too early, causing clumps and bonding to the brick face before the material has dropped cleanly into the gap. Once that residue cures, brushing will leave a mark behind.

After rain, wait for two consecutive dry days. Sweep the surface, then press a fingertip to the base of several joints; a clean, dusty fingertip means the run is ready.

Step four: brush the compound into the joints

Tip the tub onto the patio in a low pile and work the compound with a soft-bristle broom held at roughly 45 degrees to the joint lines. Sweep diagonally so the grain drops into the openings. On a herringbone bond, work in two diagonal directions to reach both the long and short joint runs.

Fill each joint proud of the surface at first. Compact it with the broom edge or a pointing iron until the compound sits 2mm to 3mm below the brick top.

That slight recess matters. A flush fill leaves compound on the arris, the top edge of the brick, where it can cure into a haze. Any joint that falls below 15mm after compacting needs more material.

Run a second diagonal sweep over the full 12 metres. Some joints appear full while a void remains underneath, especially where chamfered brick edges let the compound bridge the opening before it reaches the base.

Keep brushing until the brick faces are clear of loose grain. Every particle left on the surface when water is applied becomes a fixed grey speck. A leaf blower on its lowest setting clears the faces faster than a broom on a still day and lifts grain from the surface texture of riven or tumbled bricks.

Check the joint depth one last time along the run with a thin steel rule. The compound settles while you work, and a joint that read 15mm during filling can sit at 11mm or 12mm by the time the length is finished.

Step five: water it in

Fit a watering can with a fine rose to avoid blasting compound out of the joint. Apply water in a slow sweep across the full 12-metre run, using enough to darken every joint while keeping water from standing on the brick faces. Pooling can carry compound across the surface and leave a tide line as it dries.

The compound darkens and stiffens within minutes of wetting. Walk the run and top up any joint that has sunk below the brick top after the water has settled it, then mist that repair lightly. A second light watering an hour after the first helps moisture reach the base of a deep joint that the first pass only wetted on top.

Step six: the curing window

Geofix is firm enough for foot traffic in around 24 hours at 15 to 20 degrees, with full cure taking several days. Below 10 degrees, curing slows sharply. The first hour after watering is the fragile period, because sudden rain can wash uncured compound from the joints before the polymer has gripped.

Check the forecast for a dry overnight window before opening the tub. Keep a roll of polythene sheeting nearby in case cloud builds and the run needs cover during the early cure.

Keep dogs and wheelbarrows off the patio for the full 24 hours. A paw or barrow wheel on a half-cured joint leaves a depression that sets permanently. The polymer keeps hardening over the following week and reaches full freeze-thaw resistance by roughly day seven. That timing is why late-autumn work carries more risk than spring work: a hard frost on a four-day-old joint can still lift it.

Step seven: read the run for misses

Low afternoon light across the patio shows joints that sit low or hold a void. Walk the 12 metres with the sun behind you and mark shallow joints with a chalk line. Refill those marked joints, compact them again, and water them lightly; spot repairs blend in once cured.

An overfilled cured joint sitting 4mm proud of its neighbours can be shaved level with a pointing iron. A low cured joint is the one that needs attention before winter, because it gives rain a path into the old failure line. The only awkward cases are the joints that look full from above and turn hollow when low sun crosses the herringbone.