Silicone sealant

Flexible seal that can detach, split or conceal failed joints behind it.

What changes first

Look for edge separation, black spotting and loss of elasticity. The pattern and location usually matter more than color alone.

Moisture and movement behavior

Record whether the material changes after rain, water use, heating cycles or seasonal humidity. A material can display the damage while the source is somewhere else.

Before repair

Determine whether the material is the source, a pathway or only the final surface. Correct the controlling condition before replacing finishes.