Perimeter sealant closes the joint between a window or door frame and the surrounding wall. Exposure to sunlight, rain, temperature change and movement can cause it to harden, crack or pull away.
Why does it matter?
Open joints can admit wind-driven rain and create draughts. Repeated wetting may damage internal finishes and, where timber frames or concealed battens are present, contribute to decay. Cracking may also reveal that the original installation detail is inadequate.
What should be done?
Failed sealant should normally be removed rather than covered over. The joint should be cleaned, prepared and resealed with a compatible external-grade product. Wider gaps may require a backing material and defects to render, masonry or flashings should be repaired at the same time.
Important: General guidance cannot confirm the cause or significance of a defect at a particular property. Inspection findings must be considered alongside the building’s age, construction, exposure and alteration history.