What are the two main types of polysulphide sealants specified in this code?

Type 1 (Pouring grade) for horizontal joints and Type 2 (Gun grade) for non-sag applications in vertical or overhead joints (Clause 3).

What is the minimum application life (pot life) at 27°C?

A minimum of 2 hours for both Type 1 and Type 2 sealants (Table 1).

What is the required Shore A hardness for the cured sealant?

The hardness must be between 15 and 50 after 14 days of curing (Table 2).

Is a primer always required when using these sealants?

Yes, a compatible primer is required to be applied to joint surfaces before sealant application to ensure proper adhesion (Clause 4.3).

IS 12118 Part 2

: 1992

Polysulphide based sealants - Specification

CurrentSpecializedSpecificationBIMMaterials Science · Waterproofing and Damp Proofing

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This standard specifies the requirements for two-part polysulphide based sealants used for sealing joints in buildings and other structures. It classifies sealants into Type 1 (Pouring grade) for horizontal joints and Type 2 (Gun grade) for vertical or overhead joints, and defines their material, physical, and performance characteristics.

Specifies requirements for polysulphide based sealants used in building construction.

Quick Reference Values

Classification Type 1Pouring Grade (self-levelling)

Classification Type 2Gun Grade (non-sag)

Minimum Application Life at 27°C2 hours

Maximum Slump/Flow for Gun Grade (Type 2)2 mm

Cured Hardness (Shore A)15 to 50

Minimum Adhesion in Peel0.9 N/mm

Maximum Weight Loss after Heat Ageing10 %

Practical Notes

Proper joint preparation, including cleaning and priming as per manufacturer's guidelines, is critical for achieving the specified adhesion performance.

The pot life (application life) is highly sensitive to ambient temperature and humidity; mix only the amount of material that can be used within this period.

Ensure the correct grade (Pouring vs. Gun) is used for the joint orientation to prevent sagging in vertical joints or to ensure proper levelling in horizontal ones.