Frequently Asked Questions

What are the main quality advantages of Renderoc Ready Plaster over a site-batched cement-sand plaster?

Site-batched plaster using bulk cement and river sand has several inherent quality risks that are largely eliminated by Renderoc Ready Plaster. The cement-to-sand ratio in site batching is measured by volume (head pan or wheelbarrow) rather than by weight — this introduces significant variability batch to batch because the bulk density of sand varies with moisture content. A slightly lean batch (too much sand) produces weak, sandy plaster prone to cracking and poor adhesion. A slightly rich batch (too much cement) produces plaster that is prone to drying shrinkage cracking. The sand used in site-batched plaster is usually river sand with variable grading and clay content that is not controlled — clay in the sand increases shrinkage and reduces strength. Renderoc Ready Plaster uses graded clean aggregate at a precisely controlled cement ratio with a polymer modifier that further reduces shrinkage — the result is consistently better performance across all these quality parameters.

Does Renderoc Ready Plaster need a bonding primer on concrete surfaces before plastering?

A bonding treatment is recommended on smooth, dense concrete surfaces before applying Renderoc Ready Plaster to ensure adequate adhesion. Very smooth concrete surfaces (such as those cast against steel or phenolic-faced formwork) have low surface porosity and limited mechanical key for a cementitious plaster. A bonding slurry of cement and Nitobond SBR latex, or a dedicated bonding primer, should be applied and allowed to become tacky before the plaster coat is applied. On rough concrete surfaces (such as those against sawn timber shuttering or block-faced formwork), the surface provides adequate mechanical key for direct plaster application without primer, provided the surface is clean and pre-wetted to saturated surface-dry condition before plastering. On masonry, brick, and AAC block walls, the surface is typically absorbent enough for direct plaster application without primer — pre-wetting the substrate is recommended to prevent rapid absorption of water from the fresh plaster.

Can Renderoc Ready Plaster be applied externally and how does it perform in Indian monsoon conditions?

Yes. Renderoc Ready Plaster can be used for external wall plastering and is suitable for exposure to Indian weather including monsoon rainfall. The polymer modification in the product provides improved water resistance of the hardened plaster compared to a plain cement-sand plaster — the hardened plaster has lower water absorption and reduced permeability that helps resist rain penetration through the plaster coat into the wall construction. However, Renderoc Ready Plaster is a cementitious plaster and should not be considered as a waterproofing material — it reduces water penetration but does not provide a waterproof barrier. For external walls requiring waterproof protection, a subsequent coat of a Fosroc waterproofing system (such as Brushbond RF or Nitoproof 600) over the cured Renderoc Ready Plaster is the recommended approach. Fresh Renderoc Ready Plaster must be protected from rain for a minimum of 24 hours after application.