What is the recommended soluble bitumen content for waterproofing mastic?

It should be between 14% to 17% by mass as per Table 2.

What is the maximum allowed heating temperature for bitumen mastic?

The mastic should not be heated above 200°C to prevent degradation and loss of volatile properties of the bitumen.

What type of filler is required for the mastic mix?

Mineral fillers like limestone powder or Portland cement with an ash content of not less than 70% must be used.

IS 1345

: 1982

Bitumen mastic for waterproofing - Specification

CurrentSpecializedSpecificationMaterials Science · Waterproofing and Damp Proofing

Archive.org BIS Portal Google

This standard specifies the composition, preparation methods, and physical properties of bitumen mastic used for waterproofing and damp-proofing in structural elements like roofs, basements, and swimming pools.

Specifies requirements for bitumen mastic used as a waterproofing material, primarily for roofs and floors.

Quick Reference Values

Soluble bitumen content14 to 17 percent by mass

Maximum heating temperature200 °C

Hardness number at 25°C10 to 20

Ash content of mineral fillerNot less than 70 percent

Practical Notes

Ensure the concrete or masonry substrate is thoroughly completely dry and primed with an appropriate bitumen primer before laying the mastic to prevent blistering and debonding.

Bitumen mastic must be laid hot (typically 180°C to 200°C) using wooden floats; continuous stirring in the mastic cooker is critical to avoid localized overheating and segregation of aggregates.

Avoid applying bitumen mastic directly over joints in the structural deck without proper isolation or joint detailing, to prevent cracking of the mastic layer.