Applying “plaster” cement

There’s a lot to learn when you are forced to switch what you know about building from the West, to Asia. Here in Indonesia there tends to be teams of workers who all support each other with a set of skills that define the group. For example, builders get the structure physically into place, but they don’t finish walls in order for them to be ready for paint. Another example: laying a concrete floor. In this case the builders get the columns, beams, steel rebar and wire mesh into place. They build wooden forms that will hold the wet concrete in place. Then the floor pouring team arrives and within five hours the floor is poured and most of the evidence of maybe a dozen or more crew members having been on your site is gone.

Currently there are two teams at our site: builders and cement finishers. The cement finishers are doing a good job of trying to get a feel for what kind of end result I want.

To understand the material involved, we need to separate concrete from cement. You use cement to make concrete, by mixing sand, crushed rock and water. Cement is a binder, usually using lime, and the hydrologic cement we use requires water to harden, with the addition of sand.

The “plaster” part of the process is the application of cement to a wall or ceiling in order to make it smooth. When concrete is poured during construction it sometimes adheres to the wooden forms that held it in place, and so small chunks tear away. In addition cement has a different appearance than concrete, as concrete has pebbles and cement has sand. Using a wet sponge on a fresh cement layer as a final “coat” makes the wall or ceiling feel smooth to the touch. Missing chunks can be filled and wall edges can be smoothed out. Depending on the style you’re after it can be appealing to:

1. leave the surface alone
2. add wax to shine it up
3. add a clear coating to make the it stain resistant
4. or paint / wallpaper the dry, smooth surface

Photo above: plumbing and electrical wiring is installed alongside “finished” cement walls. In this case the walls will enclose a basement room for the electrical panel and backup generator.