Water penetrating the exterior sealant can travel behind the finish. In wood-framed buildings, this causes the framing lumber to swell (dimensional instability) and then rot, leading to permanent cracking. In steel-framed buildings, rust expansion (volume increase of up to 600%) can generate tremendous jacking forces, producing severe horizontal cracking.
The primary causes of cracking can be categorized into four domains: cracks around window frame
A common non-structural cause is the "drywall butt joint" positioned directly over the window edge. If drywall sheets are hung without proper staggering, the natural seam may align with the frame. Without adequate tape and compound reinforcement, this seam cracks inevitably. Additionally, insufficient shimming or over-tightening of fasteners can pre-stress the frame, inducing immediate cracking after initial occupancy. Water penetrating the exterior sealant can travel behind