My husband and I poured a concrete shower pan with lightweight leveling mortar more that a week ago. We used a preslope and quick pitch kits. There is a rubber membrane and hardibacker underneath. We just noticed a hairline crack across 3 of the sections about a foot from the drain. We worked each section and packed them with our hands to be sure they were full. How serious is this and what can we do to fix it? We plan on coating it with Redgard.
Nina