How should the trowel be held against the wall when plastering with Portland cement used for exterior application?

• A. Slight angle
• B. 45 degree angle
• C. Flat
• D. 90 degree angle

Answer: (A)

Holding the trowel at a slight angle to the wall is key for exterior Portland cement plaster because it lets the blade press and smooth the mix into the surface without scraping it away. A slight tilt (nearly flat against the wall but tipped a few degrees) helps pack the cement, fill pores, and create a uniform finish while maintaining a good bond to the substrate. If the trowel were flat, you’d tend to drag and smear, thinning the coating and leaving drag marks. If it were held too steep or at 90 degrees, you could gouge the plaster and pull material off the wall. The slight angle gives you control, a smooth finish, and proper bonding for the exterior plaster.