How are line markings and playground markings applied on school and council surfaces?

Markings are the last thing applied and the first thing noticed. They are also the item most often compromised by programme pressure, because they need a dry surface, a cured substrate and time to cure themselves.

The surface has to be ready

Four conditions, and all four are needed.

**Sound.** Paint on a surface that is cracking, delaminating or dusting will fail with the surface. Which means the repairs happen before the markings, not after.

**Clean.** Dust, oil, rubber, moss and residual curing compound all prevent adhesion. Preparation is a mechanical clean rather than a sweep, and on an existing asphalt or concrete surface it is most of the labour.

**Cured.** New asphalt needs time before it is marked, and new concrete needs longer. Marking too early produces discolouration, poor adhesion or both, and the waiting period is not negotiable regardless of the handover date.

**Dry.** Not just the surface. A slab or an asphalt layer holding moisture will push a coating off from underneath, and a surface that looks dry after rain can still be releasing water.

The resurfacing work that precedes this is covered in [asphalt resurfacing on a live school playground](/answers/how-is-asphalt-resurfacing-done-on-a-live-school-playground).

Matching the system to the substrate

Different surfaces take different products.

**Asphalt** needs a coating formulated for a bituminous substrate, because some solvent-based products soften it.

**Concrete** needs a product that tolerates the alkalinity of a relatively new slab, and frequently a primer.

**Acrylic sports surfaces** are marked with a compatible acrylic within the same system, not with a general purpose line paint.

**Synthetic turf** uses inlaid lines of a different coloured fibre rather than paint wherever the markings are permanent, since paint on synthetic fibre wears off and has to be reapplied.

Using a product outside the system it belongs to is the most common cause of markings that fail within a season.

Setting out, which is where the accuracy matters

For a sports court the dimensions are governed by the sport, and they are not approximate.

Court dimensions, line widths, the position of the run-off and the clearances behind the lines all come from the relevant governing body's specification, and a court marked a little short is a court that cannot be used for competition. The requirement is the same as the one applied in [how a multi-use sports court is built](/answers/how-is-a-multi-use-sports-court-built-for-a-nsw-school) and in the cricket facility requirements in [cricket pitch and training nets](/answers/how-is-a-cricket-pitch-or-training-nets-facility-built-to-cricket-aust).

Where a surface carries several sports, the colour hierarchy and line priority are agreed in advance so the primary sport reads clearly. A court with four sports in similar colours is unusable for all of them.

For play markings, the set-out is a design exercise rather than a dimensional one, and it is approved with the school before application because changing it afterwards means removal.

Dealing with existing markings

Three options.

**Remove,** by mechanical means or by waterblasting, which gives the cleanest result and can leave a shadow on the surface.

**Cover with a blackout coat,** which conceals the old lines and gives a uniform base for the new ones. The usual answer on a court being remarked for a different sport.

**Overpaint,** which only works where the new line covers the old one completely.

Leaving old lines to read faintly through new ones is the outcome to avoid on a competition surface, because it creates ambiguity about where the line actually is.

Timing against the operating programme

The surface has to be out of use through preparation, application and cure, which on a school site means a holiday period or a weekend, and in cool or damp weather the cure takes longer than the programme assumed.

Which is why the marking is programmed with weather contingency rather than on the last available day, and why wet weather on a marking job cannot be recovered by working harder. The recovery options are those in [wet weather and programme recovery](/answers/wet-weather-and-programme-recovery).

Barriers and signage keep the area out of use through the cure, since footprints across fresh markings cannot be repaired without reapplication.

Handover

The as-marked layout, the product data sheets for the system applied, the date of application, and the expected maintenance interval.

That last item is worth stating plainly: markings are a wearing item with a life measured in a few years on a trafficked surface, and planning the reapplication is cheaper than discovering it when the court is unusable.