Cementitious External Rendering from JPS Coatings

PolyBoard Render is a cementitious external rendering solution from JPS Coatings. While other popular JPS Coatings renders like Pro-Render and Ezi-Build apply to brick and masonry substrates, PolyBoard Render is specially designed for use on low absorbency substrates, such as pre-coated Polystyrene and Expanded Polystyrene Sheets (EPS).

A Closer Look

Fueled by 29 years of experience, JPS Coatings came up with the PolyBoard Render formula using cement, washed silica sand, and various powder additives. The result is a premixed cementitious external rendering material that delivers high-strength adhesion to any clean, sound and non-weathered

EPS surface. PolyBoard Render is also the ideal choice for base coat application to off-form concrete, smooth masonry, and other difficult, low absorbency (uncoated) masonry substrates.

Cementitious External Rendering with PolyBoard Render

Cementitious external rendering with PolyBoard Render can be applied in four stages, as follows:

Prepare the designated surface. The substrate to be applied on must be of sound structural integrity. The applicator must make sure that the substrate is free of dirt, oil, grime, dust, and all powdery residues. Such contaminants may break bonding of PolyBoard Render to the substrate.
Prepare PolyBoard Render. PolyBoard Render comes in a dry powder form supplied in 20kg bags. The approximate coverage of 1 x 20kg bag of PolyBoard Render is 6 to 8m² at an average thickness of 2mm. The adhesive state is achieved by mixing 1 x 20kg bag of PolyBoard Render with 5 to 5½ litres of clean water. The correct, lump-free consistency is produced using a power stirrer or any similar device. This smooth paste is desired for excellent adhesion and minimal drying shrinkage of the product. The amount of water to be used may vary in accordance with ambient temperature and the desired consistency. JPS Coatings recommends a settling time of 5 to 10 minutes before re-drilling the product. No more water should be added to prevent excess mixing that may induce surface crazing, cracking, and delaminating.
Apply the cementitious external rendering solution. The applicator must use a hawk and trowel to apply the PolyBoard Render paste and in single upward strokes from the bottom of the substrate. The thickness of a single layer must be between 2mm to 6mm, with the best results finishing off at 4 to 6mm. The applicator must take care not to overwork the surface area. For application to Extruded Polystyrene Sheets (XPS), a priming process is in order, along with the addition of JPS Bonding Agent.
Let cure. PolyBoard Render will normally dry in 2 to 8 hours with desired conditions of 25°C temperature and 50% relative humidity. Lower temperatures and higher relative humidity will prolong the curing process. After 7 days, the applicator may overcoat the substrate with any texture coating. The applicator should only apply PolyBoard Render at temperatures between 10°C to 30°C.

Feel free to get in touch with JPS Coatings for more information on cementitious external rendering. Call their hotline at 1300 577 262 or visit their website at www.jpscoatings.com.au today.