Rendering Features

• Rendering is the application of a material mixture, such as acrylic or cement, to a wall using a trowel or roller to apply the mixture evenly across the wall's surface. After applying the material and allowing it to dry, the surface becomes hardened against the elements. This added layer forms an aesthetically pleasing protective barrier as well as a paintable surface on which you can add color to your home's exterior.
  
  

Acrylic Renders

• Acrylic is a unique material comprising a mixture of plastic polymers and petroleum that provides its strong and flexible structure. Acrylic-based renders offer better water resistance than cement renders, as well as higher strength against the piercing sun. Though the final appearance of acrylic renders is comparable to cement renders, acrylic is less prone to cracking over time. Additionally, acrylic renders are applied in a thin layer -- about 4 millimeters thick -- that allows for rapid drying times of about three to five days, after which the surface can be painted.
  
  

Cement Renders

• Cement, lime, and sand are mixed together to form a cement render. The cement mixture attaches to the home's exterior walls in a layer about 10 millimeters thick. Cement's chemical composition requires a curing time, so the rendering cement mixture must be left to dry, or cure, for about four to six weeks before you can paint it.
  
  

Rendering Innovations

• Some construction companies have created a "top coat" system for rendered building walls; previously applied cement renders can be rejuvenated with a clear coat of an acrylic polymer mixture. This acrylic mixture drys on top of the cement's texture and into any cracks, forming an additional barrier against the elements.
  
  

Consumer Considerations

• Concrete rendering application is relatively common in the construction industry. However, acrylic rendering applications require an experienced professional versed in the many effects the rendering offers as it is layered onto the wall. Fresh Look Plastering suggests contacting the specific acrylic render manufacturer for approved contractors trained in applying their particular mixture. In addition, you can speak to other homeowners with acrylic renders for their contractor recommendations.