Illustrations by Steph Bravo
The Dutch have climate-proofed their homes that are meant to float as sea level rises. Solar panels are gaining more visibility. Many cities have green roofs, vertical gardens and climbing plants for natural heat insulation.
We all are doing what we can to adapt to and mitigate climate change. The Arctic ice meltdown is going at a faster rate than projected.
Homes are the biggest energy guzzlers. They consume so much resources and excrete proportionate amounts of waste. Architectural issues and environmental issues have become intertwined as people demand houses that are cheaper to cool, nicer to live in, and are more earth friendly.
There are five basic elements that make a home green, as I have written and explained in this column for many years now.
They are: sustainable site; water efficiency; indoor environmental quality; energy efficiency; and material efficiency.
Sustainable site
1. The ideal lot in relation to thermal comfort in the tropics, has the long sides of the lot facing the north and south. This minimizes exposure to direct sunlight on the east-west axis.
The sun path and the shadow of neighboring buildings will determine how much solar access there is to be able to install solar panels and solar water heaters.
2. If the lot orientation is not ideal in relation to the sun path, wide roof overhangs may be placed to shield the house from the sun. The windows may also be slightly recessed from the walls. Sunshades may also be used as protection from the sun’s direct heat and glare.
3. Quality of neighborhood, availability of water, accessibility to public transportation, existing electric power grid, flood-free location are qualities of a sustainable site. House design should take advantage of beautiful views.
4. Build at least 100 meters away from sites exposed to electromagnetic fields (EMF), brought about by the presence of high tension transmission lines. Avoid sites near sources of pollution like industrial and livestock sites.
5. Avoid brownfields or sites damaged by previous building or industrial activity. These sites require extensive remediation to remove toxins such as lead, asbestos, gasoline, diesel, motor oil, pesticides or other environmental contaminants.
6. Minimize site disturbance, develop the land with the least damage and in a harmonious way. Strive to incorporate impervious materials for roadways and parking places. Use paving blocks to reduce heat island effect caused by trapping the earth’s heat with solid concrete outdoor spaces.
Water efficiency
7. Xeriscaping or the use of drought-resistant plants conserves water. Watering lawns and gardens with treated or potable water is wasteful.
8. Water-saving bathroom fixtures and faucets can help conserve water.
9. Graywater recycling minimizes the use of fresh water. It is channeling water from sinks, showers and washing machines into a filter that could be a concrete tank with sand in the upper half, and gravel at the bottom. By gravity, the filtered water flows to a cistern and is pumped directly to toilet fixtures.
10. Storm water runoff must be removed from the site as quickly as possible. Swales are a natural drainage system that allow storm water to collect in downward sloped turfs or detention ponds from roads and pavements.
11. In open undisturbed land, 60 percent of rainwater reaches the aquifers, the rest is released into evaporation and transpiration. In urban spaces, only 10 percent reach the aquifers, while 75 percent becomes runoff water. A good way to manage rainwater is through rainwater harvesting from the roof into tanks or cisterns for watering plants and cleaning.
12. Green roofs and vertical gardens act like a sponge absorbing rainwater and delaying its release, giving the street time to flush out and discharge storm water. Green roofs could use edible plants for healthy urban farming, aside from cooling the house and beautifying the landscape.
Indoor Environmental Quality
13. Source of fresh air should be far from pollutive areas and sources of contaminants.
Typical air rates depend on the number of house occupants. Windows should be at adult body level for better air change. The size of the windows is related to total wall and floor area.
14. Indoor materials affect IEQ. Volatile organic compounds or VOCs are carbon-based chemical solvents distilled from petroleum or petroleum by-products. They are hazardous to health. VOCs and other toxic materials are widely used in construction and interior decoration materials. The present standard for VOCs specify outgassing levels at around 0.5 milligrams per cubic meter.
15. VOCs are found in plywood and some flooring materials made with polyvinyl chloride, lead-based paint, glues and adhesives, maintenance and cleaning products that are petrochemical- or solvent-based. Molds, mildew and house dust, mites and cockroaches cause allergies and other sicknesses. Indoor plants reduce temperature and enhance IEQ.
16. Burning wood creates significant amounts of fine particle pollution. It contains thousands of chemical substances, including carbon monoxide, nitrogen oxide, benzene, formaldehyde and dioxin, one of the most toxic substances. Many of the toxins in wood smoke are the same as those found in cigarette smoke.
17. Indoor air quality is particularly acute in bathrooms and kitchens with very poor ventilation due to excess moisture in the air. This in turn condenses on cold surfaces where mold is formed. Molds cause respiratory illnesses. One way to improve conditions is by installing large window openings or installing exhaust fans or to put ceramic wall tiles only in wet areas such as shower stalls and around the lavatories.
18. Noise pollution is a big source of stress in today’s modern world. Many big cities install sound barriers to shield houses near the highways from noise. A green home can use living screens like shrubs, earth mounds and trees.
Energy efficiency
19. Passive design refers to building design that does not require electromechanical equipment for heating or cooling. This deals directly with the building envelope (meaning, exterior walls and roof which should be light-colored, doors and windows), how it is oriented in relation to the solar path, cross-ventilation, what materials are used, what external features such as sunshades and landscaping are utilized to cut down use of energy.
20. Green active design refers to the sustainable use of artificial environment technology to heat, cool or light a space. Lighting takes up 20 percent of energy bills, while air conditioning consumes 50 percent on average.
21. Using energy efficient lighting technology can bring up to 40 percent savings in energy cost. This can be done by applying lighting where it is needed and with the use of digital control provided by LED lights. Photocells or light sensors in combination with passive design features like daylighting help reduce energy use.
22. Today’s air conditioning equipment include inverter types which consume less energy. It is more expensive with two years payback depending on the amount of use.
23. Energy-efficient appliances have Energy Guide labels. The labels help to compare the efficiency or annual energy use of competing brands and similar models. Look for the yellow and black labels on washing machines, refrigerators, freezers, room air conditioners, lamps and ballasts.
24. To verify if your home is energy efficient, you can adopt the energy efficiency index computation as follows—divide the annual electricity consumption in kilowatt-hours by the house floor area in square meters. The resulting energy efficiency index should not go far above 15 kWh/sqm/year.
Material sustainability
25. When a new building is constructed, materials recovered from demolished buildings can be reused not only to reduce construction waste but also to reduce the embodied energy associated with building materials. Embodied energy is the energy needed to produce building materials starting from the extraction and processing of natural resources up to manufacturing, transport and delivery.
26. When renovating homes with asbestos, it’s best to minimize activities in areas where damaged materials may contain asbestos. Avoid damaging asbestos material. Do not dust, sweep or vacuum debris that may contain asbestos. Do not saw, sand, scrape, or drill holes in asbestos materials. Don’t sand or level asbestos flooring. Asbestos is a toxic material. Many homes built in the 1970s and earlier have asbestos.
27. CCA-treated wood posts, planks, fences and tables that little children with hand-to-mouth characteristics touch, is a serious health concern.
CCA, which stands for chromate copper arsenate, is an extraordinary preservative that has been injected in pressure-treated boards, ordinary planks and posts to extend the life of wood five times. This prevents lumber from rotting when exposed to sun, rain, termites and fungus. The bad news is CCA is a form of arsenic which we know is very poisonous.
28. In building construction, steel, in the form of I-beams for columns and posts, facilitates faster construction. It also can span wide distances between supports. With the tensile strength of steel in combination with the compressive strength of concrete, modern architecture and engineering made technological advances.
29. To many people, gypsum is commonly known as a material used for drywall panels. They are either nailed or screwed in place to form a finished wall. It is resistant to fire and heat and can easily be cut using simple construction tools. It is abundant, economical, versatile and reasonably strong.
It helps to reduce sound. Gypsum is also used as a popular ingredient in cement mixtures due to its hardening properties.
30. Reduction of waste in construction should be worked out from the beginning of a project between architect and contractor. For example, the architect can prevent waste by designing within the standard dimensions of building components such as reinforcing bars, roofing materials, ceiling panels, etc. Excessive waste will result if these standard sizes are not used.
31. Composting or burying wet kitchen garbage in the ground is a green practice.
Pay a visit to your Barangay Eco Center for solid waste management in the community, or contact your homeowners’ association for segregated solid waste disposal systems.
32. Green fire safety measures include choosing the right materials. Minimize the use of wood especially for ceiling and roof eaves. Gypsum board and cement board are the preferred materials. They are not only fire-resistant but also termite-resistant. For townhouses, dividing firewall between units must be half a meter above the roof, made of concrete.
The author is the Principal Architect of A.P de Jesus & Associates-Green Architecture; and vice chair and COO of the Philippine Green Building Initiative
For comments or inquiries, email amadodejesus@gmail.com