Signs of seasonal rainwater seep in from window sill.
As seen by infrared images water flow noted from side of window sill & side reveal. The moisture is originated due to Water pocket & gap in external sill stone. Two separate stones have been used in external sill. If not rectified, moisture will spread in adjacent areas and cause further damage.
1. Slope to be repaired at window sill to avoid water stagnancy.
2. Sealing the gap in external sill with UV resistant exterior grade silicone sealant as per manufacturer specification.