Plaster Cracking in Older Homes

Plaster is older, harder, and less forgiving than drywall. It cracks on houses that have been standing for decades and are not in distress.

Why plaster talks

  • It is brittle
  • The lath and framing behind it still move with humidity
  • Old settlement that finished years ago is still written in the coat

Plaster is a hard, rigid material applied over wood lath, and unlike drywall it does not get replaced every time a room is remodeled. That means a plaster wall can be carrying decades of ordinary seasonal movement in its surface — cracks that opened years or decades ago from settlement that has long since finished, simply because nothing since has smoothed them over.

What it does not automatically mean

When plaster is a clue instead of the whole story

  • New cracks after a long quiet period
  • Offset or stair-step through masonry that is also changing
  • Change that tracks with moisture at the foundation

How MFRC suggests homeowners think about it

Instead of asking "how old is this crack," ask "was it here before, or is it new?" An old house with old, stable plaster cracks is not describing a current problem. A long-quiet wall that starts cracking again after years of nothing is worth a closer look.

Related dictionary terms

(Each of these terms is explained in the MFRC Foundation Dictionary.)

A final note

This page is educational, not diagnostic. Age of the house is context. Age of the crack is the better question.

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