Rain Harvest Home in verdant Mexico boasts water autonomy and simple living

Proyecto: Casa Cosecha de Lluvia
Publicación: STIR world

Casa Cosecha de Lluvia by Robert Hutchison Architecture and JSa Arquitectura is a series of three low forms featuring a catchment with a reservoir system that purifies harvested rainwater.

Rooted in and heavily influenced by its dramatic, breath-taking and verdant location, the Rain Harvest Home in Temascaltepec, Mexico, conceived as a collaboration between Robert Hutchison Architecture and JSa Arquitectura is exactly what its moniker makes known - Casa Cosecha de Lluvia reveals itself as a society of three distinct forms, a main residence, a detached art studio and a bathhouse, that integrate rainwater harvesting at the core of its distinct architecture. A sustainable and off-grid haven, Rain Harvest Home displays a picturesque and sturdy example of what sustainable architecture defined strictly by context can be, how the built can form symbiotic friendships with its surroundings, in reverence and in celebration of the nature it abides by.

Residing in the mountains a couple of hours west of Mexico City, the unassuming project encompasses permaculture principles to establish an all-inclusive, integrated relationship between people and place. “Here, as in the surrounding region of Central Mexico, water has become an increasingly precious resource as temperatures rise and populations increase. Although the region sees a robust rainy season, rainwater harvesting is not common; instead, pumping in water from distant watersheds is standard practice. Rain Harvest Home takes a different tack, proposing an integrated approach to designing regeneratively with water,” shares Javier Sanchez, who is also the client, as he lives in the home with his wife and two daughters. Currently a family retreat, the project will transition to a permanent residence soon.

STIR reached out to the creators of the nature-infested sanctuary, Robert Hutchison, AIA, Robert Hutchison Architecture, and Javier Sanchez, HFAIA, JSa Arquitectura, to understand how the trio of low-lying buildings with green roofs achieve 100 per cent water autonomy.

Jincy Iype: What drives the core concept and functioning of the Rain Harvest Home? How is it a “net-zero” retreat?

Javier Sanchez: Rain Harvest Home is located within Reserva el Peñón, a landscape-driven development which has achieved water self-sufficiency for a community of 80 families across 450 acres of a nature reserve, two hours from Mexico City. Within this Reserve, each home is required to incorporate rain harvesting, with most of it coming from the individual home’s rainwater harvesting system and a small portion coming from the reserve’s reservoirs. We wanted to try and raise the bar and see if we could harvest 100 per cent of our water from our individual site, rather than depend on external sources.

Personally, this was essential because we have a major water shortage in Mexico City, which is absurd because it rains a lot, but we do not harvest that plentiful rainwater. Instead, we pump water in and out of the valley. As designers and architects, we need to address such blatant issues within our works and experiment with new possibilities. Sometimes when you have a built example, it is much easier to understand these new possibilities, particularly around rainwater harvesting, as proof.

Jincy: Can you tell us more about how the Reserve influenced the design, how is it experimental and how rainwater is properly harvested?

Robert Hutchison: The Reserve really framed our thinking around sustainability generally, specifically, of rainwater harvesting. In a great way, it pushed us to think at a much larger level, where the whole Reserve became the site, and the home was one piece of that. And then thinking about how the larger issues of water conservation in Mexico could be explored here, where this could be an example of how to harvest rainwater on a small scale that could then apply to other projects. That became a driver in a powerful way. It was an idea that really evolved over the course of the design process. The client became increasingly interested in cultivating a healthy, holistic lifestyle where they could live in harmony with the land.

Now, the rain harvesting system and on-site reservoir are a learning laboratory where the clients are continually learning about how the system performs. The home is 100 per cent water autonomous and, in times of surplus, it is water positive and feeds excess water back into the community’s larger reservoir system. Understanding that the water and food systems on site are part of a living process that fluctuates depending on changing natural conditions, the client continues to experiment with ways to optimise the system through seasonal calibrations and refinements.

Javier: The project is an ongoing experiment, to see what is possible with rainwater harvesting within a closed-circuit system. Nothing is as objective as science would make it seem because things are always changing over time depending on how much it rains, and when. The house has to live with that, and it is a constant learning experience for us as designers. It’s about integrating design into the cycle of water and of life

Jincy: Who is the client and what was their brief to you?

Javier: The brief was simple: the clients wanted a small cabin to enjoy the verdant, mountainous site.

Robert: The clients had been camping on the site for a year, so the cabin idea developed out of that.

Javier: We were inspired by the house Alvar Aalto built for himself in Muuratsalo, Finland. It is a really small space, and so for us, this word, “cabin”, went along with the human scale of the house. We wanted something cabin-like as opposed to building an expansive house.

Valle de Bravo has a dry season and a rainy season, and the sun plays a trick every day in both of those seasons. You can enjoy the sun, but you have to be careful with it. Here, you need to have spaces that are open and covered; enclosed and covered; and outside and uncovered. You need all three qualities, so we needed to make that happen within this shelter.

Robert: This drove the idea of a platform to occupy the land, and hovering above it is a roof plane that provides a huge outdoor shelter.

Javier: You go to sleep in the small, comfortable, cosy spaces that are quite small, and almost Nordic in aesthetic and materiality, and then you open up the house to enjoy the powerful, healing landscape.

Jincy: The Rain Harvest Home enjoys its location immersed deep in nature – how is dialogue ensured between the built and the natural?

Robert: The site is relatively flat, but sits within a mountainous environment. All around, there are cliffs and steep slopes, but our site rests on a small plateau that is vegetated with continuous, single-story high shrubs and brush. Because of these site conditions, we wanted to see if we could make the buildings disappear within the vegetation. This is why we designed a series of three low pavilions that nestle into the landscape and are dispersed across the site. We wanted a strong connection between each building and the landscape.

Often as architects, we think about how spaces are created between buildings, but this was about letting the landscape be that interstitial space. The landscape becomes the connection between the buildings, just as it delineates the spaces between them. When you move through the site, there’s an experience of the buildings constantly disappearing and reappearing. It’s a process of discovery, where you don’t see everything all at once.  

We also responded to the quality of light and how it changes over the course of the year, depending on the weather and the angle of the sun. With the main cabin, which is essentially a large rectangle, we wanted to make sure the interior portions were able to receive natural light. That’s where the roof monitors became important as ways to scoop light down into those interior spaces. There are light monitors in the main bedroom, one in the den, and the largest one is over the kitchen. 

Jincy: Do you want to tell us how the distinct positioning and shapes of the extended skylights, as well as the inclusion of green roofs for the trio of structures, came about?

Robert: All three of the structures have green roofs, meaning they can hold moisture because they have a gravel and soil roof condition. Excess water (especially when it’s rainy) gets collected on that roof and piped over to the reservoir to feed into the water system. All three of the buildings were thought of as rain catchment systems in that sense and required flat roofs to be able to collect the rain.

We were also thinking about how to get natural light down into the buildings. We also extended that idea to the bathhouse, similar to the main cabin. We liked the idea of each of the four bathing spaces in the bathhouse (hot bath, sauna, steam shower, and washroom) having no visual connection to the exterior, but we wanted to bring sun or moonlight down into those volumes through a skylight. The light coming down into each of these spaces changes depending on the time of day. Finally, the studio is really just a large light and viewing monitor, bringing light indirectly into the studio with a view of the nearby hillside, and then the roof deck is an aperture for viewing the sky.

Jincy: What inspired the subtle materiality and colour scheme of the residential architecture?

Javier: We wanted to work with Robert because he has experience building small, efficient, beautiful cabins in the forest. Most of them have a similar dark exterior, with blackened cedar.

Robert: We like using this dark exterior treatment because it helps the houses recede and become engrained in the landscape. Of course, you still see the structure, but somehow the black siding helps it become a background condition rather than foregrounding it.

Jincy: What are the similarities as well as differences between the three structures? How are they connected?

Robert: At the start, the contextual design had a simple, classic program: two bedrooms, a bathroom, and a kitchen. When Javier was on the site, we started developing the idea of splitting up the program into separate buildings. It started with wanting to separate the function of bathing from the rest of the cabin, which is where the idea of the bathhouse came from. And then the separate studio also emerged from that.

Regarding the main cabin, the only parts that really wanted to be enclosed were the two bedrooms and the small den, and a small bathroom with laundry and storage. That was officially the cabin, conceptually everything else is outdoors. The living/dining area is separated from the outdoors with sliding glass doors, but when the doors are open, the idea is that you are completely outside. This drove the idea of a platform to occupy the land, and hovering above it is a roof plane that provides for a huge outdoor shelter.

Javier: In Mexico, the culture often drives weekend homes for city people in rural locations to be the same homes that we have in the city. The idea of having the bathhouse separate was part of the challenge of living differently. It also relates culturally to how Mexicans live outside of the city. In rural Mexico, the bathroom is always separate from the place where people sleep. It also connects to having a reverence towards the bath as a space that connects man to water, which goes so far back in history. With the bath, we wanted to create an experience that was completely about water and people, and that had to be outside of the house. Splitting it into three buildings also had to do with keeping the scale small, and also to do with enjoying the land. Because once you have everything in one building, then you’re not invited to go through the land to get to another part of the house. Experiencing the land was important to the project.

Robert: Within the Reserve, there are numerous walking trails which run through our site. The project picks up on those trails and they become what connects each of the three buildings. It was important to us that we weren’t treating the buildings as a larger ensemble that then became a compound, complemented by a full battery of solar panels. Instead, we wanted the buildings to disappear into the landscape. You might just see a corner of a building popping out, but you don’t relate to them as three buildings together. It’s beautiful because you can just take a trail, and then you’ll end up at a building. It’s this element of surprise.