Gypsum Plaster

Gypsum Plaster for Interior Wall Leveling — Lightweight, Crack-Resistant & Fast-Setting

Gypsum Plaster by JOSME is a dry-mix interior wall leveling material, formulated with high-purity Calcium Sulfate Hemihydrate and perlite lightweight inorganic aggregate. It serves as a viable replacement for traditional cement-sand mortar, suitable for concrete, brick and AAC block substrates. The product solves common on-site construction issues including shrinkage cracking, poor adhesion on smooth concrete and long curing cycles. With bulk density ranging from 700–1,100 kg/m³ and compressive strength reaching ≥2.5 MPa, the product adopts 25kg bag packaging and follows ISO 9001 quality management system for batch production.

What Is This Material and Where Does It Fit?

Gypsum Plaster is somewhat unlike from the cement mortar that depends on the hydraulic hardening mechanism, Gypsum has a modest volume expansion during the setting period that successfully prevents the shrinkage stress and map cracking on the cement rendering layers. Perlite aggregate provides basic heat insulation and sound absorption capabilities and decreases the total wall load. Added cellulose ether and retarder polymer ingredients provide for extended on-site working time and better adherence on low-porosity smooth surfaces.

This product is only suitable for dry inside environment, such as living room wall, bedroom wall, corridor wall and inside ceiling base layer. Cannot be used on external walls, bathrooms, kitchens, balconies and other places exposed to long-term wetness or frequent wet-dry alternation.

Technical Parameters

Gypsum Plaster Characteristics

Lightweight & wide coverage The bulk density of this plaster is 700–1100 kg/m 3 , which is substantially lighter than standard cement mortar (2000 kg/m 3 ). Low density enhances coverage per unit weight, decreases structural strain on buildings and saves on-site material consumption and human handling expenses.

Crack & Delamination Resistant The near-zero shrinkage formula and ≥0.4 MPa bonding strength eliminate the usual faults of cement mortar, such map cracking, hollowing and surface powdering. The cured wall surface will have stable dimensions under normal building and curing circumstances.

Fire resistance Class A1 The gypsum matrix includes around 21% chemically bound water, which is released as vapour at elevated temperatures and inhibits the spread of fire. The fireproof performance is achieved by the inherent property of the material without any further coating treatment.

Workflow Status Stable The setting time of between 60 and 120 minutes offers the workers enough time to trowel and level the wall. Good mechanical properties are achieved within a short period after setting, enabling further finishing activities on the same day of construction.

Sound Absorption & Thermal Insulation Its thermal conductivity is 0.15–0.25 W/m·K, lower than that of cement mortar, which limits heat transmission through interior partition walls. Basic sound absorption benefits of additional perlite aggregate are good for residential wall and ceiling construction.

Quality Control

All the batches of the plaster are checked in five stages professionally before shipment, so that the product performance is stable:

Setting Time Test: Check the acceptable working time in the field by performing the Vicat Needle test according to ASTM C472.

Bond Strength Test: Pull off test to check the bonding strength is ≥0.4 Mpa or higher than the norm.

Fineness & Grading Inspection: Control the particle size of the aggregate to prevent an uneven surface texture of the wall.

Water Retention Test: The rate of water retention should be more than 90% to fit the high-suction substrates.

Shrinkage Monitoring: Carry out routine drying cycle tests to determine the dimensional stability of the material.

The complete manufacturing process follows ISO9001 management criteria, ensuring the mineral purity and additive proportion are stable for each batch.

Ordering and Supply

JOSME supports bulk engineering orders and small renovation orders for global B-end customers:

Standard products can be delivered within 2–3 working days; customized formula and private-label orders take 7–15 working days. In-stock goods can be dispatched promptly according to inventory status.

We provide packaging customization and private-label branding services, and support sea, air and land freight with complete customs declaration documents.

Frequently Asked Questions

Q1: Can this gypsum plaster be used in wet areas like bathrooms and balconies?

A1: No. This product is only for dry interior spaces. Long-term moisture and wet-dry alternation will damage the bonding performance and surface integrity, so it cannot be used in humid areas.

Q2: Will cracking or hollowing occur after the plaster hardens?

A2: With standard construction processes, the low-shrinkage formula and stable bonding strength effectively prevent cracking, hollowing and powdering, keeping the wall surface stable in long-term indoor use.

Q3: How to control construction progress within the 60–120 minutes setting window?

A3: Mix materials in batches according to on-site construction volume. Use clean containers for mixing, and discard partially set materials instead of reusing them to ensure uniform wall construction quality.

Q4: What base surfaces are compatible with this product?

A4: It fits concrete walls, brick walls, AAC blocks and interior ceiling bases. All substrates need to be clean, firm and free of dust and loose impurities before construction.

Contact Us

If you have technical inquiries, sample applications, bulk procurement and customization demands for Gypsum Plaster, please contact our team via [email protected].