Casa AYA: Latin America’s sustainable marvel combining straw bales and Passive House Standard

In the department of Canelones, Uruguay, a modest but groundbreaking architectural gem has emerged. Casa AYA stands as a testament to innovation, combining straw bale construction with the rigorous Passivhaus standard

Casa AYA: Latin America’s sustainable marvel combining straw bales and Passive House Standard

In the department of Canelones, Uruguay, a modest but groundbreaking architectural gem has emerged

Casa AYA stands as a testament to innovation, combining straw bale construction with the rigorous Passivhaus standard

Casa AYA: Latin America's sustainable marvel combining straw bales and Passive House Standard
In the department of Canelones, Uruguay, a modest but groundbreaking architectural gem has emerged – Casa AYA. Designed by Martin Comas of Arquitectura Regenerativa, this eco-friendly dwelling redefines sustainable living in Latin America. Casa AYA stands as a testament to innovation, combining straw bale construction with the rigorous Passivhaus standard, marking a significant milestone in the region’s environmentally conscious architecture.

Redefining conventional construction

Casa AYA challenges conventional construction practices by achieving a remarkable 70% reduction in the use of concrete compared to traditional building methods. The design team achieved this impressive feat by using locally sourced timber on raised foundations and straw bale insulation, a design decision that reflects the essence of the project: reducing the environmental impact of the built environment while providing a super comfortable, healthy home with absurdly small energy bills.

Straw bale innovation

The core innovation of Casa AYA lies in its use of prefabricated, compressed wheat straw panels for the floor and wall panels. These modules, crafted by a local company called BioFraming, provide a sustainable alternative to traditional construction systems, reducing the home’s environmental footprint and contributing to superior energy efficiency.

compressed wheat straw panels for the floor and wall panels at Casa Aya

Passivhaus and thermal excellence

One of the standout features is its Passivhaus compliant, thermal bridge-free envelope. With a minimum of 20 cm of thermal insulation meticulously integrated into the floor, walls, and roof, the house is optimized for energy efficiency. Such attention to detail ensures that the home maintains a comfortable and consistent indoor temperature throughout the year.

Passivhaus and thermal excellence at Casa Aya

Martin Comas, project architect, explains the path he’s trodden to get here and his recent immersion in the world of Passivhaus

“Before 2019, our constructions were made of concrete, brick and glass, without much real or conceptual technology. That was until I came across Passivhaus. It was a before and after thing…It’s something that opens your mind and gives you tools to take architecture to a much higher level.”

“At first, Passivhaus seemed very German to me…like, very far away. And I wondered…can this be done in Uruguay? Will I be able to find suppliers, labour, know-how and so on…and at reasonable cost? Basically, I was asking myself: is it possible?”

“With this project we not only showed that it was possible, but also, we added some layers of difficulty. For example, we set out to have the smallest possible carbon footprint (using compressed straw wherever possible). And we also set out to build it cheaper than local standard construction, with local labour and in a similar timeframe. In the end we were able to achieve all these goals. It was very challenging, but we are very proud to have managed to raise the bar for construction in Uruguay (which- to be honest- is very low).” 

Km zero and draught-free

To further celebrate its connection to the local environment, the walls of Casa AYA were plastered with clay sourced directly from the site, creating a harmonious union between the building and its surroundings. Furthermore, a mechanical ventilation system with heat recovery was installed, providing excellent indoor air quality with minimal heat loss. The Blower Door airtightness test yielded a result of n50=1.2 ach: not enough to achieve one of the project goals of PHI Low Energy Demand certification, but nonetheless, around 10 times more draught-free than standard construction in the area. When combined with controlled ventilation, reducing draughts and air leaks improves thermal comfort, reduces heat loss and energy bills, and minimizes the risk of moisture damage and unnecessary maintenance costs.

The walls of Casa AYA were plastered with clay sourced directly from the site
Casa AYA stands as a testament to innovation, combining straw bale construction with the rigorous Passivhaus standard

Casa AYA is more than just a home: it’s a symbol of sustainable innovation and a testament to what can be achieved when modern design meets an environmentally conscious mindset. This pioneering project in Carrasco, Uruguay, sets a new standard for environmentally friendly construction in Latin America, proving that we can live in harmony with nature while enjoying the comforts of contemporary living. Casa AYA’s successful integration of modular straw bale construction with the Passivhaus standard serves as an inspiration for architects, builders, and homeowners looking to embrace a more sustainable future.  

After handover, we have asked the architect: what would you recommend to someone when buying or renting a home?

“I would recommend that, if you can, go visit someone who already lives in a Passivhaus, so you can hear a person explain, in a real and non-technical way, what it’s like to live and feel a high-performance house, designed and built for the climate of the next 50 years. That- I think- is fundamental for anyone who is thinking of building a house.  When our clients, who’ve have already been living in these kinds of houses for a while, go to visit their parents or friends, they always comment on how different it is to live in a house with even temperatures in all spaces, damp-free, comfortable and with great air quality”.

Congratulations to Martin Comas and the team at Arquitectura Regenerativa, for designing and building one of the most sustainable homes, not only in the country, but also in the region. Do you want to build or retrofit a nearly-zero energy learning space with excellent air quality, great comfort, and absurdly low energy bills? Contact us and let’s talk through your project.

Images: Martín Comas

Project featured at Passive House Accelerator