War on Heat 1: The Cover Up.
WINTER IS COMING.
Just kidding, this is the Philippines. Even through the coldest months of December to February, heat is still one of the biggest issues to issues to handle in a Filipino house.
(This is the first of 3 articles on the War on Heat. So check in soon, and see if you can’t find anything that can help you against this godawful heat.)
It’s the age old problem. Even the OG bahay kubo and the bahay na bato were developed to combat heat and humidity. It might have been a completely different era, but techniques and components like long overhangs, and permeable materials and screens were developed to keep the heat out and let the home breathe. Today, these principles still hold true as methods of keeping a home cool and comfortable.
Keeping the heat out: Covering up
Keeping your space cool is essentially a battle to keep sunlight off your building envelope. Composed of your walls and roof exposed to the elements, the more you can keep the sun off your envelope, the colder your home stays throughout the day.
While there are few options for covering your roof, every little bit helps. Although you might have limitations as to where to place them, solar or photovoltaic cells help buffer from direct sunlight while providing renewable power.
You’ll have a few more options for your walls. Extending the roof itself through longer overhanging eaves shades your walls and windows from direct sun. A long enough overhang has the added benefit of creating an informal semi-outdoor space below. Reminiscent of the old bahay kubo silong, the area is half protected from the elements and can double as a patio, or just a covered walk around the house.
Another architectural solution is to provide additional cladding or a screen on in front of your perimeter wall. This lighter second skin takes the heat so your walls and windows don’t have to. You can even use ivy or vertical planters to function as the second surface.
Taller trees and vertical planting in general like bamboo helps to shade walls similarly while having the added benefit of producing fresh air. It’s always a good idea to protect and plant greenery on site.
When you can’t keep the sun off your envelope, make sure your envelope works for you. On its surface, a material that’s lighter in color helps reflect away the solar radiation. It works opposite for darker colors as these will tend to absorb heat. (The analogy of shirts work well. Sure, it might not be flattering to be wet in your white shirt in the way that white roofs get more obviously dirty over time. But at least you’re not cooking in black.)
Insulation also helps make sure that heat stays in the skin and doesn’t go through. For dry-wall, Rockwool should help heat and even sound from penetrating. For thick concrete walls, an air gap or surface layers of gypsum should help contra heat transference.
If you ever wonder why it’s still hot in your house even after the sun’s gone down, blame it on a little something called thermal mass. Philippine houses are most commonly built out of hollow blocks. While these are great for keeping interiors cool in the daytime, the system is a complete bastard at night. Heavier/ denser materials take a longer time, and a lot more energy to change temperature. So, throughout the day, when the wall keeps your interior cool, its slowly soaking up the heat. At night, when the air is generally cooler, your concrete walls will re-radiate the heat into the air, turning your house into a pressure cooker. If you didn’t do a good enough job of covering up your wall, your best first option is to ventilate your space to get the hot air out. But you can read more on that in the second part of the War on Heat series: Designed to Breathe.
Have your own thoughts on possible ways to keep the heat of your home?
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