Can bitumen mastic be laid on a wet or damp base?

No, the concrete base must be completely dry and fully cured (minimum 28 days) to prevent blistering of the mastic layer.

What is the correct temperature for laying bitumen mastic?

It should be laid hot, typically between 170°C and 200°C. Temperature should be strictly monitored with a thermometer.

How is the finished surface achieved?

The hot mastic is spread with a wooden float to the required thickness and rubbed to a smooth finish. Fine sand or stone dust is often rubbed into the surface while it is still warm to improve slip resistance.

IS 1196

: 1978

Code of practice for laying bitumen mastic flooring

CurrentSpecializedCode of PracticeArchitectural · Flooring, Wall Finishing and Roofing

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This code covers the preparation of the base, heating, laying, and finishing procedures for bitumen mastic flooring. It is primarily used by site engineers and contractors to ensure a durable, jointless, damp-proof, and heavy-duty wearing surface for industrial and commercial floors.

Code of practice for laying bitumen mastic flooring

Quick Reference Values

Maximum heating temperature for bitumen mastic200 °C

Recommended laying temperature170 °C to 200 °C

Minimum curing period for concrete base before laying28 days

Typical thickness for light duty flooring15 mm

Typical thickness for heavy duty/industrial flooring25 mm to 50 mm

Minimum width of overlapping joints75 mm

Practical Notes

Never overheat the bitumen mastic (above 200°C) during the melting process, as this will degrade the binder and reduce the flooring's lifespan.

Ensure the concrete base is entirely dry, clean, and suitably primed before laying; trapped moisture will turn to steam under the hot mastic and cause blisters.

Any blow-holes or blisters that appear during laying must be punctured and rubbed down with a wooden float while the mastic is still warm.