Rendering is a term used to refer to the process of covering over another surface with a special cement mixture to give a smooth and even covering on the entire applied area. You can render any stone or porous surface, especially other cement like cement sheeting. If you have an old, discoloured, stained, or just plain unattractive slab of cement sheeting, you can easily apply rending over it yourself to give the whole area a facelift.
Scrape down the entire surface of cement sheeting with a steel wire brush. You need to remove any loose particles as well as dirt and oil from the sheeting.
Wash down the cement sheeting with a damp sponge to remove any dust created by brushing it. The surface should be clean and wet when you're done.
Mix the base rendering by combining equal parts cement and lime powder in a wheelbarrow and adding six parts coarse sand. So, if you are using 1 pound of lime and 1 pound of cement, add in 2.72 Kilogram of coarse sand.
Dig a channel down the middle of the powder mixture with a shovel and pour the water into it. Combine the wet and dry materials until you have a thick, even consistency throughout the rendering.
Pile a heaping amount of rendering onto a metal float and spread it upward onto the cement sheeting. Spread the rendering out until it is 10mm thick.
Apply the rendering onto the sheeting surface this way until it is covered with an even coat. Use a trowel to smooth the edge between application patches.
Let the base rendering dry for 3 days until it is firm and solid to the touch. Mist the rendering occasionally with a spray bottle of water to keep it from cracking as it dries.
Make another batch of rendering for the topcoat by following the same recipe you used for the base rendering. The only difference is that you should use sharp, fine sand instead of coarse sand.
Apply the topcoat in the same way as with the base until the base rendering is covered. Lightly mist the rendering and let it rest for 3 hours.
Drag the edges of a trowel or other implement through the still soft rendering to create designs. If you want to leave the rendering smooth, skip this step.
Let the topcoat set for 3 days, misting the rendering occasionally like you did with the base coat.
For coloured rendering, add pigment to the wet rendering when you mix it or paint over the dry, set rendering after completing the installation.
Do not apply rendering over crumbling or loose cement sheeting or the rendering will be unstable and will likely fall off.