Water-filled pores expand during freezing and progressively detach the surface.
Failure path
- Step 1: Masonry absorbs water.
- Step 2: Temperature drops below freezing.
- Step 3: Pore water expands.
- Step 4: Surface stresses accumulate.
- Step 5: Scaling and fragments appear after repeated cycles.
What makes this pathway plausible
The timing, location and operating or weather trigger should repeat. A diagram shows a mechanism; evidence from the actual house determines whether it applies.
Best next observation
Record the trigger and compare the nearest materials, components and routes before opening finishes or choosing a repair.
Verification after repair
Recreate the original trigger when safe, then confirm the symptom does not return and affected materials are stable or drying.