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close this bookAppropriate Building Materials: a Catalogue of Potential Solutions (SKAT, 1988, 430 p.)
close this folderExamples of roof materials
View the documentEarth reel roofs
View the documentSoil brick roof
View the documentClay tile roofs
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View the documentCorrugated fibre concrete roofing sheets
View the documentFibre and micro concrete tiles
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Clay tile roofs

KEYWORDS:

Special properties

Durable, waterproof cladding for sloped roofs

Economical aspects

Low to medium costs

Stability

Good

Skills required

Skilled labour

Equipment required

Clay tile production unit, roof construction equipment

Resistance to earthquake

Low

Resistance to hurricane

Medium to good

Resistance to rain

Very good

Resistance to insects

Very good

Climatic suitability

All climates, but most common in humid areas

Stage of experience

Traditional

SHORT DESCRIPTION:

· Burnt clay tile roofs are only used for sloping roofs between about 20° and 50° inclination of rafter, and the tile shapes differ for each range of slope. It should be remembered that the rafter pitch is always steeper than the tile pitch (see illustration overleaf).

· Clay tile production is a traditional village craft in many regions, but uniform shapes and qualities are difficult to achieve. Mechanized plants produce good quality tiles, but at higher costs. An appropriate intermediate solution is provided by mobile presses with interchangeable moulds for different tile shapes (see ANNEX: Machines and Equipment).

· Depending on the clay type and production method, a major problem of clay tiles is the immense loss (in India about 35 %) due to cracking and breakage. A good remedy has been found in the use of ammonium chloride as an admixture varying between 0.1 and 1.0 %, depending on the type of soil (Bibl. 00.41).

· Clay tiles are heavy, requiring a strong substructure and closely spaced battens. Therefore, tile designs (eg Mangalore tiles), which require wider spacing of battens, are lighter and more economical. But generally, the weight of the roof and loose connection of tiles, make them susceptible to destruction in earthquakes.

· Good quality tiles with good overlaps are perfectly waterproof. The red colour, however, tends to absorb solar radiation, so theta suspended ceiling may be needed for indoor comfort.


Relation of Rafter Pitch and Tile Pitch; Other Clay Roofing Elements; Some Typical Clay Roofing Tiles and their Minimum Rafter Pitch (reduced by 5°, if the tiles are placed over a waterproof membrane)