Andean Ichu Thatch

Andean ichu thatch is the traditional grass roofing of the high Andes of Peru, Bolivia and neighbouring countries. It is made from coarse bunchgrasses of the altiplano, chiefly ichu (Jarava ichu, formerly Stipa ichu), a name that comes from the Quechua word for straw. The grass is also known as Peruvian feathergrass, paja brava and paja ichu, and grows from Mexico and Central America through the Andes to Chile and Argentina.

Inca roofs

The Inca state, which flourished from about 1425 until 1532, built its famous fitted-stone walls but roofed most buildings with thatch. According to the World History Encyclopedia, Inca roofs were made of grass or reed thatch laid on poles of wood or cane tied together with rope. The poles were secured to the stone walls by projecting stone pegs, either set into the masonry or carved from the same block, and some gable tops carried a stone ring for tying down the roof. In wetter areas the pitch was steep, often about 60 degrees, to shed rain quickly.

Inca stonework of this kind survives at many sites, including Machu Picchu, founded around 1450 and inscribed by UNESCO in 1983, although the original thatch has long since perished. Large public halls (kallanka), with several doorways onto a plaza, were also roofed in this way.

Grass rope and communal work

The same grass is twisted into rope. The best-known example is the Q'eswachaka suspension bridge in Peru, which Quechua communities rebuild every year over three days. Families twist straw into thin cords about 70 m (230 ft) long, which are combined into thicker ropes and finally braided into six main cables tied to ancient stone abutments. UNESCO added the knowledge, skills and rituals of the renewal to its Representative List of the Intangible Cultural Heritage of Humanity in 2013. The tradition shows the skill in harvesting, twisting and tying grass that Andean thatching also depends on.

Thatch today

Grass thatch has largely given way to metal and fibre-cement sheet. In Peru's 2017 census, 2.9% of occupied dwellings had roofs of straw, palm leaves or similar materials, against 39.2% with metal (calamina) or fibre-cement sheets. Bolivia's 2015 household survey estimated 6.4% of households with roofs of straw, cane, palm or mud.