A newly resurfaced sports court should look clean, uniform, and professional. But after some time, you may notice lines beginning to appear through the playing surface.

They may follow existing concrete joints, become more visible after rain, or gradually develop into cracks.

At first, it can seem like a simple cosmetic problem.

But if the line is coming from an expansion or movement joint beneath the surface, covering it may not solve the real issue.

What Are Expansion Joints?

Concrete expansion and movement joints are designed to accommodate movement within a concrete slab.

Concrete can expand, contract, and experience movement because of temperature changes, moisture, loading, settlement, and other conditions. Joints provide a controlled location where this movement can occur.

When an acrylic sport court system is installed over a concrete substrate, these existing joints remain part of the structure underneath the surface.

If the joint moves, that movement can eventually become visible through the finished court.

Why Does the Joint Show Through?

The problem often becomes noticeable when the movement underneath exceeds what the surface layers can accommodate.

A resurfacing system may cover the joint temporarily, but if the underlying joint continues to move, the line can eventually reappear.

This is why simply applying another layer of acrylic coating over the affected area may only hide the symptom.

The question should be:

“Why is the joint becoming visible?”

—not simply—

“How can we cover it?”

More Coating Isn't Always the Solution

Adding additional coating may make the court look uniform immediately after completion.

However, coating thickness alone does not eliminate structural movement.

If the joint is active, the new surface may eventually develop a visible line, crack, or separation in the same location.

Repeatedly covering the area can create another problem as well: multiple layers of material may build up, potentially creating differences in texture, appearance, or adhesion.

A proper assessment should come before deciding on the repair method.

Inspect the Joint and Surrounding Surface

When expansion joints begin showing through, several factors should be examined.

Look at the condition of the concrete around the joint. Is there movement? Is the joint damaged? Is water entering the area? Are there cracks extending away from it? Is the existing coating properly bonded?

Drainage should also be considered.

Water that remains around joints or enters damaged areas can contribute to further deterioration over time.

Understanding the cause helps determine whether localized treatment, joint detailing, repair, or broader resurfacing is appropriate.

Plan the Sport Court System Around the Substrate

A professional acrylic sport court installation should begin with an assessment of the existing substrate.

Cracks, joints, uneven areas, weak concrete, contamination, moisture, and drainage conditions should be identified before the surface system is applied.

The objective is not to pretend that movement joints don't exist.

It is to incorporate the existing substrate conditions into the overall court design and installation approach.

Don't Let a Visible Joint Become a Bigger Problem

A line appearing through your sports court may look minor today.

But if it represents continuing movement, ignoring it could allow the visible defect to become more pronounced over time.

This is particularly important when planning resurfacing. A new colour coat may improve appearance, but it cannot automatically correct problems originating beneath the surface.

So, if your expansion joints are beginning to show through the court, don't simply cover them up.

Find out what is happening underneath first.

A professional assessment can help determine whether the joint is stable, moving, damaged, or affected by moisture—and what treatment is suitable for the existing conditions.

Because a successful sports court is not created by hiding every line.

It is created by understanding what is happening beneath the surface and designing the right system around it.