Pull-Off Adhesion Strength Test of Gypsum
(Gypsum Plaster Bond Strength)

In-situ measurement of the adhesion bond strength of gypsum plaster to concrete or masonry substrates — verifying application quality, substrate preparation and gypsum product performance.

Overview

What is the Pull-Off Adhesion Strength Test of Gypsum?

The Pull-Off Adhesion Strength Test of Gypsum measures the tensile bond between a gypsum plaster finish and its substrate using a hydraulic pull-off tester. A 50mm steel dolly is bonded to the gypsum surface, core-drilled around and pulled off to determine the adhesion strength and failure mode.

Conducted as per BS EN 13279 and IS 2095, this test is essential for premium interior gypsum finishes, false ceiling gypsum board adhesion, hospital and clean room gypsum wall applications and any specification requiring minimum bond strength. Global Lab uses NABL-calibrated pull-off testers for accurate bond strength measurement.

Direct Bond Measurement

Actual tensile adhesion measured — not estimated from visual or sounding survey.

Failure Mode Analysis

Adhesive vs cohesive vs substrate failure classified for root cause diagnosis.

All Gypsum Types

Machine-applied gypsum, hand-applied gypsum, gypsum board adhesive tested.

Acceptance Criterion Check

Results compared against specification (typically ≥0.3 N/mm² for premium gypsum).

NABL Certified Reports

All results on NABL-accredited letterhead per BS EN 13279.

Grid Survey Option

Multiple test points provide representative bond map across entire wall area.

Test in Action

Pull-Off Adhesion Strength Test of Gypsum — Site Images

Gypsum Surface

Tensile test

Pull-Off Tester Reading Bond Strength

Test Procedure

How the Pull-Off Adhesion Strength Test of Gypsum is Conducted

1

Dolly Bonding

50mm steel dolly bonded to gypsum surface with two-part epoxy. Cured for minimum 24 hours.
2

Core Drilling

50mm diamond core drill cuts through gypsum layer around the dolly to isolate test area.
3

Pull-Off Tester Setup

Calibrated hydraulic pull-off tester coupled to dolly via loading rod.
4

Controlled Load Application

Tensile load applied at 0.05 N/mm²/s per BS EN 13279 until failure occurs.
5

Result Recording

Maximum load, bond strength (N/mm²) and failure mode recorded. NABL report issued within 24 hours.

Standards & Specifications

Applicable Test Standards

Standard	Title	Scope	Type
BS EN 13279	Gypsum Binders and Gypsum Plasters — Test Methods	Gypsum Testing	British Standard
IS 2095	Gypsum Plaster Boards — Specification	Gypsum Board	Indian Standard
ASTM D4541	Standard Test Method for Pull-Off Strength of Coatings	Pull-Off Test	ASTM
BS EN 1542	Measurement of Bond Strength by Pull-Off	Bond Strength	British Standard

Applications

Where is the CAPO Test Used?

Premium interior gypsum finish acceptance on hospitality and residential projects

Hospital and clean room gypsum wall and ceiling bond verification

Gypsum board adhesion testing for false ceiling and partition systems

Diagnostic testing of delaminating or hollow-sounding gypsum areas

Quality assurance for machine-applied gypsum on large floor plate buildings

Warranty compliance testing for gypsum product manufacturers

Why Choose Global Lab

Our Advantages

NABL Accredited ReportsLegally valid bond strength certificates for all warranty and contractual requirements.

All Gypsum ApplicationsMachine gypsum, hand gypsum, gypsum board and tile adhesive all tested.

Failure Mode DiagnosisWritten assessment of failure mode with substrate preparation recommendations.

Pan-India CoverageField teams across 7 lab locations for rapid site deployment.

Fast TurnaroundOn-site results; NABL report within 24 hours.

Combined Façade TestingGypsum pull-off + Plaster pull-off + Tile adhesion as a complete interior finish audit.

Pull-Off Adhesion Strength Test of Gypsum(Gypsum Plaster Bond Strength)