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close this bookAppropriate Building Materials: a Catalogue of Potential Solutions (SKAT, 1988, 430 p.)
close this folderExamples of building systems
View the documentMud brick vaults and domes
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View the documentConcrete panel house
View the documentFerrocement housing units
View the documentFibracreto building system
View the documentBamboocrete construction
View the documentBamboo houses
View the documentPrefabricated timber hut
View the documentPrefabricated wooden house
View the documentTimber houses for flood areas
View the documentRha-lime prototype house

Rha-lime prototype house


Special properties

Substantial replacement of cement

Economical aspects

Medium costs


Very good

Skills required

Standard construction skills

Equipment required

Conventional building equipment

Resistance to earthquake

Very good

Resistance to hurricane

Very good

Resistance to rain

Very good

Resistance to insects

Very good

Climatic suitability

All climates

Stage of experience



· The first house to be built, using to a large extent rice husk ash (RHA) and lime as substitute for cement, stands on the premises of the National Building Research Institute, Karachi, Pakistan (also see Pozzolanas).

· Portland cement was used to stabilize the soil for the foundation (3 % cement); for compressed soil blocks (5 % cement) used to construct the plinth; for the floor; and for concrete door and window frames.

· Structural components such as the roof, beams, lintels, projection slabs (sunshade), overhead water tank, were also made with portland cement, but with 30 % of the required amount replaced by RHA and lime.

· The hollow blocks and mortar used for the load-bearing walls were made only with RHA and lime as binder, just as the external plaster.

· The appearance, structural performance and durability of the house is no different from conventional constructions, using portland cement as the only binder, but it saved 37 % of the costs and showed a way to solve a waste disposal problem.

Further information: National Building Research Institute, F-40, S.I.T.E., Hub River Road, Karachi, Pakistan; Bibl. 24.16.

RHA-Lime Prototype House at NBRI, Karachi (Bibl. 24.16)