Earthquake Movement and Window Frames

A window frame is never rigid in a seismic region, and the figures kept at san bernardino window contractor ptag online start from that rule. A window replacement in San Bernardino, CA sits close to the San Andreas Fault, and the house moves a little during every shake, however small.

What shaking does to a wall

A wood-frame wall racks sideways during an earthquake, so a rectangular opening briefly becomes a parallelogram. A frame fastened tightly in all directions can crack the glass as the opening distorts. A little clearance around the frame lets the wall move without pressing on the glass.

Clearance and flexible joints

The gap between the frame and the opening is sized so the sealant and foam can stretch. A backer rod and a flexible sealant take up small movements. Foam and sealant that bond rigidly on three sides tear. The right joint design lets the frame float slightly inside its opening.

Glass in earthquake country

Tempered glass breaks into small cubes, and laminated glass holds together after cracking. Large fixed panes near doors and walkways are usually one or the other. A big picture window with ordinary annealed glass cracks into long sharp shards, which is why code limits where it can be used.

Fasteners and shims

Fasteners are driven snug, not tight, and shims support the frame at the right spots so the weight is carried without pinching the glass. Heavy units like a bay window or a bow window are supported from below so they do not pull away from the wall. Cable or bracket supports are checked for tightness, since a loose one lets the whole unit sag a little with each small tremor and opens the joint at the roof above it.

After a quake

Following a shake, sashes that bind, cracks at the corners of the trim and new gaps in the sealant all point to movement. A quick check of the larger windows reveals problems before the next rain. Houses on the slopes near the Shandin Hills may show it more than those on flat ground. Owners are told to photograph any new crack beside its date, so a later repair can be matched against what was there before, and a gap that grows from one season to the next is looked at without delay.