Sustainable Home Designing

It’s amazing how good design can change the game. The same little blocks rearranged differently can make the difference between how a space feels, how a space performs , how much a space can cost over its lifespan, whether it appreciates in value or depreciates and whether it integrates with or blights its environment.
But the other side of home design that is just as important as beauty and functionality is pre-emption. Good design can pre-empt a great many problems, problems which could have contributed negatively to a space’s environmental pricetag. Pre-emption can make the difference between a losing battle with maintenance versus inherent resiliency due to solid design. Pre-emption can avoid a mold prone spaces chronically effecting the health of the inhabitants. Appropriate design can create barriers to pests like scorpions, preventing inhabitant paranoia and the need to fumigate. Design can avoid materials which become toxic liabilities in the environment by specifying benign materials instead. Preemption is the less glamorous side of design because it is invisible. You don’t see many pictures of preemption in the design magazines.
As promised, we are going to tackle the subject of sustainable home design in the humid tropics. Some of these tips reverberate throughout the internet, some are my personal experience. And know that, prior to building, an environmental impact study may be required by your site!
1. Elevate your floor plan. Whether you opt for stilted or platform construction, or today’s cutting edge foundation free systems (See Diamond Pier or Pin Pier foundations), even the slightest lift of the building (ex. 5 cm) cuts off ground moisture from migrating up your walls, the prerequisite to a great many problems. Footers allow for air circulation around the building envelop. They also create a limited access to rodents and creepy crawlies like scorpions: legs can be made sticky with products like Vaseline or Tanglefoot. Or they can flout slippery metal flashing that prevents pest access. Even small moats can be utilized around these restricted entry footers, as done in India. Moats containing mineral oil and water discourage mosquito larvae and evaporation. A good platform height allows for a small dog or cat to flush out any intruders below the house. At the very least, never build a house at or below grade at a property’s lowest point.
2. There is an old adage in the natural building community: design your home with a hat and boots. In other words, long, generous eaves form the extended hat of the roof. Eaves should be at least 1 m. As for boots: if your house is at grade, be sure the walls have a splash guard, with the home perimeter sloping away from the foundation. If your home is at grade, the splash guard can double as an anti-scorpion ring barrier, if it is a slippery material like ceramic tile. You want to shed water effectively and protect the foundation zone at all times. Even though gutters are not common in our area, they need to be! Gutters with properly channeled runoff water in French drains are huge anti-erosion assets.
3. Keep those walls shaded and cool! Eaves are your best friend in this regard – pergola extensions off the eaves blur the lines between home and garden, making eaves even more effective. Looking around at all the block buildings with their walls baking in the glaring sun, and being directly buffeted by severe weather, I can’t help but feel sorry for the edifice. The building is at the mercy of wherever we put it: do it and yourself a favor and give it some protection from the elements.
4. However, if walls and windows are shaded, special accommodation may need to be made for natural light. Skylights and Solatubes, strategically placed, allow for natural light to flood the interior. Consider placing them for indirect illumination, not directly over where you sit, eat or rest. I am sometimes shocked at just how much moonlight can flood our bedroom’s skylight ! You don’t want a beam of moonlight pummeling you when trying to sleep. See http://solatube.com.mx/
5. Even your roof can benefit from protection: see my Tribune article this past month on incorporating trellises and vines to buffer your roof!
6. If you have space for a carport, consider turning it into a pergola with your solar panels. Pergolas make excellent mounts for solar panels – they are generally lower to the ground and easy to access for servicing. Maintenance of panels and junction boxes can also be conducted without climbing onto your roof. The panels provide the pergola with improved rain protection while the trellis or slats of the pergola allow for air flow around the panels. And you might as well be able to park under it all! Additionally, using pergolas as panel support means they don’t need to be visible on your roof.
7. Cross ventilation and passive solar orientation have much written about them online: be sure these criteria are fundamental to your design.
8. For me, in the humid tropics, the ideal floor plan is a hybrid: an exploded floor plan with high permeability to the garden zone but including highly insulated zones. Or put another way, a house inside a house, like a Russian doll. In the center, is a room or several that are highly insulated for AC and acoustical buffering. A zone that stays cool and buffered against all that the local roosters, dogs and fiestas can throw at it noise-wise. It can also be kept comfortably warm during our sometimes surprisingly chilly winter nights here in the Bay. But radiating off of the insulated zone is a more permeable outdoor/indoor living zone. It has generous windows and doors, with extreme cross ventilation. In fact, shower areas and extreme humidity-generating appliances like dish washers should be placed here, where the humidity can be whisked away as quickly as possible. This peripheral zone is shady, breezy, thinner walled and perfect for enjoying hammock living. The concept of a “Russian doll” style tropical house, based on functionality, can be interpreted in limitless ways aesthetically.
9. If you own view points higher than your home, consider building a viewing platform with a roof (of course, this space can double as a yoga and meditation space). The roof can funnel water runoff to be channeled to a cistern under the platform. This, in turn, can gravity feed water to the rest of the property. It can also act as a water reservoir for fire emergencies.
I hope this helps you in designing the sustainable tropical house of your dreams! Next article we will continue to explore best practices in materials.

Emily Majewski
Emily Majewski is Co-Founder of PHYTOSTONE, a small firm based in Nayarit dedicated to creating advanced natural materials for home and garden.