The soldier course is the row of units set on edge around the perimeter, and it does more work than any other part of a paved surface. It takes the outward pressure of every stone behind it. When it moves, the field spreads, the joints open and the sand starts leaving, so it is worth fixing early.
Every paved surface pushes outward. Traffic, thermal movement and frost all nudge stones sideways, and all of that force ends up against the perimeter row.
Underneath that row there should be a buried edge restraint, a spike-fixed strip that holds it in position, and where there is not, or where the spikes have rusted through or been pushed out by frost, the border simply travels.
You see it as a gap opening between the border and the field, or as the border rolling outward into the lawn. Neither fixes itself, and both get worse each season because the wider the joint, the more sand leaves and the less the field holds together.
Resetting the course means lifting it, reinstating proper restraint behind it, and closing the field back up. See how edge restraint is installed, why joint washout follows a moving edge, and what sunken pavers have to do with a spreading field.
Soldier Course
How It Runs
Four steps to a border that holds
Find how far it has travelled
A string line along the original edge shows how much the course has moved and whether the field behind it has spread with it.
Lift the course and look
The restraint under the border is the thing being checked. Rusted spikes and pushed-out strip are the two usual findings.
Reinstate the restraint
New edging bedded and spiked into compacted base, which is what stops the same row travelling again next season.
Close the field back up
The courses behind are tightened back to the border and the joints across the repair are refilled with fresh sand.
Cutting In
A clean cut line is what makes a border look right
Where a border meets a curve or an angle, the field units have to be cut to land tight against it. Snapped rather than cut, or cut short and packed with sand, and the edge opens within a season because there is nothing solid bearing on the border.
Proper cuts take longer and they are the difference between a border that holds and one that is simply decorative. See how flagstone repair handles irregular edges, why edge restraint sits under the border, and what uneven walkways do once it goes.
The border has travelled outward under the pressure of the field behind it, which means the edge restraint underneath has failed or was never installed.
A buried strip spiked into the compacted base behind the border row. It holds the perimeter in position so the field cannot spread outward over time.
Only after lifting it, because the gap behind is now full of sand and soil. Pushing it back without clearing that leaves it under permanent outward pressure.
Not every one, but every one needs restraint at the perimeter. A soldier course is the most common way to do it and the easiest to reset later.
Roughly $40 to $80 per running foot depending on access and whether new edging and base work are needed behind the row.
It needs restraint, but not the same restraint. A driveway takes a vehicle turning, which loads the edge sideways, so it gets a heavier detail. A garden path holds with a lighter one, and pricing them the same is how paths get over built.
