In February 2016 the National Housing Commission, CONAVI (for its acronym in Spanish), renewed its operating rules for providing federal subsidies. New regulations established that the use of traditional materials and constructive systems such as bamboo, straw, bajareque, palm, carrizo and wood, is considered precarious, denying access to federal funds to self-construction practices with these materials.

Therefore, the first housing exercise, carried out jointly with the community of Tepetzintan through five workshops of technical training and participatory design, was discarded to receive government support, making it difficult for residents to self-construct it.

Given this scenario, together with the Tosepan Titataniske and Tosepan Ojtatsentekitinij Indigenous Cooperatives, we decided to make a second housing exercise that avoid using local bamboo species as structural elements in order to comply with the regulations already imposed by CONAVI.

This second exercise preserves the modular and prefabricated building system based on panels made with bamboo oldhamii. The construction system uses only three elements (two trusses and a panel with its variants); these elements are pre-fabricated and assembled once the structural frames have been finished, which significantly reduces site construction time. Also, the approximate assembly time is one week, reducing labor costs for a low budget project.

Once installed, bamboo panels are coated with ixtle (local tissue used to make coffee sacks) and a thin layer of mortar. Once the base structure has been placed, the beams and subsequently the ecolam sheet are fixed. This last one is a product made from food-grade aluminum waste, which gives thermal, acoustic and antibacterial properties.

In addition to local materials, which allow the villagers to contribute in kind and labor to reduce the cost of their homes, the project has an optimum environmental performance. In the case of water, rainwater harvesting is used, as well as wetlands for reuse of gray water and biodigestor for sewage treatment. As for the climate, basic bioclimatic strategies were implemented to combat the region high temperatures.

In terms of space, the house responds to the customs and traditions of Nahuatl people, who employ a main hall where they locate the altar - the central element of the house - and dry the coffee and corn crop. The kitchen has a permeable character to let out the smoke of the firewood and the design of traditional lattices is recovered.

The second exercise was awarded by CONAVI with a silver medal in the "First National Rural Housing Contest" and approved to receive federal subsidies. However, we will continue to seek the viability of the first exercise as we firmly believe that traditional building materials and vaconstructive systems must be endorsed by public housing policies in our country and promote the autonomy of indigenous peoples, the value of vernacular architecture and conservation of intangible knowledge.