The Pool Wash LLC on Instagram: "Mastic is the flexible joint between your pool coping and the concrete deck. Its job is to absorb movement and prevent damage as the ground shifts and temperatures change. When mastic fails, it stops protecting the pool structure. 🚨 Signs Mastic Needs Replacement Cracked, brittle, or missing material Gaps between the pool and deck Weeds or ants growing in the joint Water leaking into the deck or under the pool shell These issues allow water intrusion, which can