Guest post contributed by Amelie Lawrence
Concrete exposed surface is suitable for all sorts of floors, from domestic to commercial applications. It can tolerate heavy traffic, so it is commonly used for driveways, warehouses and walkways. The appearance of exposed concrete floor depends on the installation method and the materials used. It has a wide range of color, design, and texture variations. Concrete is exposed because of its number of benefits. Exposed concrete is especially ideal for flat surfaces. The topmost portion of the concrete surface is usually unformed, while the lower portion of the concrete surface is molded. To achieve the required texture on the external unformed portion some post-finishing methods are used such as brushing, usage of chemical retarders, etc. But the internal concrete requires polishing to expose aggregate.
The following are the two methods to form a smooth and polished patina to concrete surfaces:
- Diamond polished: Here the final visual appearance of the concrete floor depends on the magnitude of concrete exposed aggregate section. This method forms a very smooth and shiny aggregate post finish. Basically, the topmost layer of the concrete surface is crushed using a diamond grinder and then the surface is polished to achieve the desired finish. The outer appearance of the finished floor is determined by the color of the cement and type of aggregates used. The degree of aggregate exposure depends on the depth of the grind. This method is highly effective for finishing existing floors.
- Pan floated or troweled: Unlike the polishing method, this process needs to be performed before the concrete is completely set. So, timing is a critical factor here. As the name suggests, the surface is floated and then troweled to give a natural glossy appearance. Here we need some power tools for floating and troweling. Here also, the color of the floor after finishing is determined by the color of the pigments and cement in the mix.
Texture and Pattern of the Exposed Concrete
Concrete exposed surfaces usually have a rough surface, so if you need slide and slip resistance surface then concrete aggregate exposed surface is worth considering. There are a number of methods to remove the uppermost mortar from the concrete surface.
- Brushing and Washing: This is most the easiest and simplest aggregate exposure method. The surface of the concrete is washed using water and brushed using a scrubber until the desired level is reached. The entire process should be completed before the concrete is set. Here you are not using any specialized tools. So, this method is mostly suitable for small projects.
- Use of Chemical Retardants: Here a chemical retardant is sprayed on top of the finished surface. Chemical retardant literally extends the flexibility duration of the surface, so the workers will get an extra day or two to create concrete exposed You can give an intensified look to the surface by contrasting cement color with the aggregate. Skill and experience is important for the successful execution of the procedure.
- Shot or Grit Blasting: In this method, the topmost hard surface of the concrete is mechanically removed to create a decorative and smooth concrete surface. Careful execution of the procedure is important to maintain the consistency of the surface. The degree of shot blast is measured using test patch. Here, as you scrap the surface deeper and deeper, the exposed aggregate becomes even larger.
- Brushed or Dragged Concrete: If the aesthetic factor is less important for you, then this is an ideal method to create concrete exposed surface. Brushing and dragging concrete is a cost-effective method to form a slip resistance surface. Pattern and texture of the surface after finish depends on the direction of drag. A simple bristled broom is used to brush the concrete surface, and dragged surfaces include “tine finish”, “Hessian drag”, or “Turf drag” to create different textures.