Final answer:
A plaster stop or plaster bead is the material used to provide a straight edge on a surface that will be plastered. Plaster stop can be made of different materials such as metal or plastic, depending on the requirements of the plastering job.
Step-by-step explanation:
The material that is permanently or temporarily attached to a surface to be plastered, providing a straight edge, is commonly known as plaster stop or plaster bead. This helps create a clean, straight edge and ensures the plaster thickness is consistent. Plaster stop can be made of different materials such as metal or plastic, depending on the requirements of the plastering job.
The material that is permanently or temporarily attached to a surface to be plastered and provides a straight edge is called a plasterer's screed. A plasterer's screed is typically a wooden or metal strip that is used to level the plaster and ensure a smooth and straight surface.
For instance, like the adhesive mentioned that is mixed with powder to create a paste for Undark, which is then painted on to adhere firmly to a surface, plaster stop attaches to edges or corners, providing a guide for the plaster application. In the scenario described by Steven, the true masonry might have had such a material to guide the plastering before the plaster and paint obscured it, although the straight edge was not a priority in mimicking the stone joinery.