Final answer:
Straight narrow cracks along the edges of tape after joint treatment are indicative of edge cracking, which is often caused by thermal stress leading to material expansion and contraction.
Step-by-step explanation:
Straight narrow cracks along the edges of tape after joint treatment are signs of edge cracking. This type of cracking can occur due to several factors, such as the thermal stress within a structure, materials contracting at different rates, or improper application of joint treatment materials.
Forces and pressures created by thermal stress can cause materials to expand and contract, leading to cracks in various applications, like plaster walls in buildings or even roadways and railroad tracks.
Mudcracks on edges of any curved application, for instance, are recognizable because they are typically wider at the top and progressively narrower toward the bottom, making them easy to spot. However, the scenarios mentioned for edge cracking pertain specifically to the movement and stress within building structures and the materials used within them.