Guide To Basic Rendering Techniques
The exterior and interior walls of any building or home need a coat of plaster material for improved strength. Render also adds fireproof and weatherproof properties to the foundation of any structure. For internal surfaces, plastering creates an acoustic sound barrier and prepares the area for decorating with paint or wallpaper.
Rendering and plastering require skill and practice to master. Nevertheless, even small DIY projects involving plasterwork are achievable. Before you consider taking on a plastering project, consider the recommendations below.
Choosing the right render
There are various rendering materials used today. The most basic exterior render usually contains cement, sand, and some filler. For interior rendering, plasterers often use gypsum-based plaster material. Plasterboard or brickwork is the background surface for gypsum-based plaster. For low suction background surfaces, applying a basecoat precedes plastering. The basecoat acts as a barrier to prevent moisture absorption before the Parex render dries completely.
The right plaster material depends on the surface to which you will apply it. You can find a variety of Parex supplies suitable for different background surfaces and finish. Examples include Parex paraguard, monorex GM, and monorex gf.
Preparing surfaces for rendering
A crucial step to ensuring a quality finish is removing dirt and debris from the surface. Wash off any oil and paint residue before applying the basecoat. Basecoat is necessary when the background surface has low suction. A commonly used basecoat to enhance plaster absorption is a mixture of PVA glue and water.
Mixing plaster material
The mix ratio of render material determines the resulting finish. Follow the manufacturer’s guidelines for the correct ratio of render and filler. For convenience, you can buy pre-mixed Parex rendering supplies where you only need to add the right amount of water. Apply water in small quantities to get the desired consistency.
Applying plaster material
Novice plasterers can use wooden battens as a guide to get the right thickness. You can nail these at the edges to create a clean, even plaster finish. Slowly apply the plaster in swift, stable motions. With the aid of a straight edge, you can level and smoothen the resulting plastered surface. The plaster coat should be allowed to dry completely before adding another layer.
Choosing the right plaster finish
You can apply different finishing techniques on the last coat of plaster for decorative purposes. Below are different types of plaster finish:
- Trowel finish. The simplest way to finish a layer of plaster is to use a wooden float to skim the surface and create a smooth surface.
- Sponge finish. To create a sponged effect, use a damp sponge and mop it over the plaster surface. The sponge should not be too wet, or it will wash off the render.
- Roughcast finish. Instead of applying the render carefully onto the surface, it is flicked and thrown to create a rough finish. This type of finish is suitable for exterior walls.
- Textured finish. Coarse aggregate such as pebbles or gravel is added to the plaster mixture to create this finish.
Plasterers are also recommended to consider ambient temperature before applying plaster. When the weather is too hot, plastering earlier in the day is ideal so that heat in the background surface will not absorb the water out of the render.