What is the recommended slope for a mud phuska roof?

The finish should be laid to a minimum slope of 1 in 40.

How much straw needs to be mixed into the mud?

Approximately 18 kg of chopped wheat straw (bhusa) should be added per cubic meter of soil.

What type of soil is suitable for mud phuska?

The soil should contain 10 to 20% clay and 30 to 50% sand, free from gravel and coarse organic matter.

IS 2115

: 1980

Code of practice for flat-roof finish: mud phuska

CurrentSpecializedCode of PracticeArchitectural · Building Construction Practices incl. Painting, Varnishing

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This code specifies the standard practices for laying mud phuska flat-roof finishes, a traditional and cost-effective technique used primarily in hot-arid regions of India for thermal insulation and waterproofing. It details the required soil properties, surface preparation including bitumen application, preparation of the soil-straw mix, laying procedures, and final paving with burnt clay brick tiles.

Code of practice for flat-roof finish: mud phuska

Quick Reference Values

Roof slope minimum requirement1 in 40

Wheat straw (Bhusa) addition rate18 kg per cubic metre of soil

Required clay content in soil10 to 20 percent

Required sand content in soil30 to 50 percent

Average consolidated thickness of mud phuska100 mm

Bitumen application rate for primer1.7 kg per square metre

Practical Notes

A coat of hot bitumen must be applied to the roof slab as a moisture barrier before laying the mud phuska.

The soil-straw mixture must be allowed to rot for at least 7 days before application to ensure proper workability and minimize future shrinkage.

Proper consolidation using wooden rammers is critical to prevent water stagnation, and the final surface must be finished with brick tiles pointed with cement mortar.