Lightweight, inexpensive, low maintenance, long duration, weather resistant roofing materials were historically few.
Neither asphalt shingles nor cedar shakes are perfect (you historically would for example have preferred cedar shakes to be more fire retardant, today cedar shakes are chemically treated with fire retardants but still have other problems), but they were frequently among the best choices. Both are quite dark after aging.
Painting asphalt or cedar shake roofs white historically would have significantly increased both installation and maintenance costs. Before the last decade or so few homeowners would have been willing to bear that increased cost.
And yes, pottery or stone roofing materials are used in some areas. These are also dark, heavy, and frequently expensive to install, often with a corresponding increase in useful lifespan.
Cedar actually turns white with age. But most cedar roofs today are treated to maintain the darker "new roof" look rather than age naturally to a ghostly white.
Because it's the cheapest solution. Unfortunately they act as heatsinks during the day, and radiate the heat during the night, never letting the surroundings cool.
Montreal has made white roofs mandatory for new construction and major repairs/replacement [1]. Large swathes of the city consist of dense residential construction, two- and three-story walkups arranged in rows, all with flat roofs.
If you do a flyover, it's easy to tell who'd had their roof redone in the past several years. I imagine with time, this will reduce the "heat island" effect in the urban environment.
Weather extremes driven by climate change hit low-income communities harder. The reasons include poor housing and lack of access to safe and comfortable public spaces. This makes “climate readiness” a pressing issue for governments, city planners and emergency services in fast-growing areas such as Western Sydney.
We work with culturally diverse residents and social housing providers in Western Sydney to explore how they’re adapting to increasing heat. Residents hosted heat data loggers inside and outside their homes.
[ ... ]
The authors would like to acknowledge the contribution of all co-researchers in the Climate-Ready in Social Housing team.
It doesn’t require that much water. This is how family homes in the balkans and southern Europe have been cooled for decades. But now it seems at least the balkans is just one big air conditioner
Spraying salt water around a city would be a dramatic solution, near suicidal imho. The salt will remain, literally salting the earth and killing plant life in the city. And the rust. I wouldnt want to own a car, business or anything made of metal in that city.
This is basically a technique that's been used for possibly millenia in Persian deserts. It doesn't require great amounts in many configurations. In fact the drier the surrounding air the more effective it is.
Dry air makes the water evaporate more quickly, but it doesnt cause the water to carry away more heat when it does so. Per unit heat, you will use as much water in dry air as in air with some moisture. You will get more cooling out of a smaller area/device, but wont use less water to do so.
And if that were all they were doing you'd be right. But it's not. High humidity impedes radiative cooling (they use both evaporative cooling as well as radiative cooling). Low humidity allows their design to cool more efficiently then it would in a high humidity environment.
These things are extremely well studied by people who know what they're doing. I'll never not be impressed by the ability of a random on an internet forum to 'well akshully'.
But the radiative cooling is going to happen with or without the water. It is a different system operating within the same device. Routing air underground to cool it will work regardless of water, at least until things heat up underground, which can be a thing in low-conductivity soils.
No discussion of solar-powered solutions. I once had a house with solar-powered attic exhaust fans. They only came on during hot days and rapidly cooled the house a few degrees when they did. Zero maintenance and they didnt even need to be wired. What we need are small DC air conditioning units that can be powered directly by solar panels without the hassle of batteries or inverters.
Evaporative cooling only works in low humidity environments, in which sweating is also effective, and raise the indoor relative humidity to 100%. Also you need water and lots of it, the more water you can evaporate the better. Evaporative coolers IMO are less effective than open ventilation and shade.
That is a really cool idea! I want to try this at some point!!
The idea of the solar-powered attic exhaust sounds nice, searching for Solar Attic Fans finds me some interesting products on some shops! Had never thought about looking for it.
Also look into products for RVs. They are always looking for easy-to-install solar solutions. My advice would be to not put the fans on the roof, but somewhere sheltered like a gable end so you dont need to worry about waterproofing.
My friend has this wonderful home automation set up. When it's in the high 60s and low 70s, his HVAC will shut off. Then actuators on his windows will push them open to let in the cool air. Then when the temperature drops too low, the windows close and the HVAC comes back on.
> it’s better to draw on residents’ local know-how than plan for climate change from above
That knowledge seems to boil down to cold congee and driving to air-conditioned spaces?? Where is the local know-how on cooling and how does that replace city planning?
It seems this research is more preoccupied with their own process and cute/patronizing “I retreat”, “Chasing the air”, “Making the air” made up categorization than practical findings. Feels like cargo cult design thinking. We have zero new insights after reading the whole piece.
> These “last resort” shelters depend in most cases on a reliable electricity supply, which can be cut during heatwaves.
Sounds like the problem is a failed government that can’t provide reliable base-load electricity generation. But the article acts like its citizens fault, we should live in a third world country and everyone should adapt by using wet towels or fans or something. Utter nonsense that provides no answers or real solutions.
On a surf trip, I'd venture to guess you were on the ocean in a high humidity environment? How well did the wet floors cool the air above them? I'd expect it wouldn't be that much if the humidity was close to 100%.
I do climate organizing, I’m on a climate commission with my city, and I work as an engineer.
I will say that everything engineers hate about “waterfall” development, local communities hate about technocratic top-down solutions raining down to “help them”.
I see a lot of comments here saying we need to fix the energy system, make distribution more reliable, add solar and DC air conditioning to houses. These solutions are valid and can do wonderful things for people in the right situations. We need to be conscious of the communities we’re serving when we make these proposals.
I worked with my city on a microgrid proposal last year for a low income part of the city. The project proposed solar, storage, rain water harvesting, and multimodal transportation, low cost reliable electricity. When I talked to members of the community where the project would go in they were totally against it. They told me that whenever the city plans projects like that, developers swarm in, buy up properties in the neighborhood, on the anticipation that the property values will go up, and raise rents, causing residents to need to leave.
The value of engaging communities and finding their solutions is that you build understanding of their needs. You also learn what they are already doing, which might be cheaper, more scalable, or more responsive than technical solutions by themselves.
But wont any solution that makes an area more pleasant also lead to increased property values? Would they be in favor of solutions that decrease property values? Or is this just nimbyism against any change?
They would be in favor of measures that would balance out the tendencies of the market and protect low income and working class people, such as rent control.
Not much new in this article. It would be interesting to see how age-old building techniques from the global south can be adapted to the increased urban density, as well as combined with the sun-angle difference as the average heat creeps up in the global north.
With the advent of air conditioning, "architects" designed houses ignoring climate and passive cooling/heating techniques. Cookie cutter designs increased economies of scale, and now we have whole swathes of dwelling land that is reliant on active cooling and heating and with the negative impacts of excessive energy usage and high cost, these things have become nightmares. Houses aren't built to stand on their own as habitable places, but require ongoing cost to do so. To rephrase, houses are not as habitable as they once were. Even with all the technological developments with regard to insulation they're less efficient than well ventilated old wood and plaster homes that have no insulation. The design paradigm for homes is not good.
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[ 6.0 ms ] story [ 96.5 ms ] threadA house in my neighborhood has white shingles.
So dark makes the house cooler, faster, when the sun isn't shining.
Lightweight, inexpensive, low maintenance, long duration, weather resistant roofing materials were historically few.
Neither asphalt shingles nor cedar shakes are perfect (you historically would for example have preferred cedar shakes to be more fire retardant, today cedar shakes are chemically treated with fire retardants but still have other problems), but they were frequently among the best choices. Both are quite dark after aging.
Painting asphalt or cedar shake roofs white historically would have significantly increased both installation and maintenance costs. Before the last decade or so few homeowners would have been willing to bear that increased cost.
And yes, pottery or stone roofing materials are used in some areas. These are also dark, heavy, and frequently expensive to install, often with a corresponding increase in useful lifespan.
Montreal has made white roofs mandatory for new construction and major repairs/replacement [1]. Large swathes of the city consist of dense residential construction, two- and three-story walkups arranged in rows, all with flat roofs.
If you do a flyover, it's easy to tell who'd had their roof redone in the past several years. I imagine with time, this will reduce the "heat island" effect in the urban environment.
1: https://montreal.ca/en/how-to/renovate-flat-roof-or-low-slop...
Having a sprinkler with a timer which can release just enough water to cover your roof helps too.
https://en.wikipedia.org/wiki/Yakhch%C4%81l
These things are extremely well studied by people who know what they're doing. I'll never not be impressed by the ability of a random on an internet forum to 'well akshully'.
The idea of the solar-powered attic exhaust sounds nice, searching for Solar Attic Fans finds me some interesting products on some shops! Had never thought about looking for it.
It's not elegant, but I love the solution.
That knowledge seems to boil down to cold congee and driving to air-conditioned spaces?? Where is the local know-how on cooling and how does that replace city planning?
It seems this research is more preoccupied with their own process and cute/patronizing “I retreat”, “Chasing the air”, “Making the air” made up categorization than practical findings. Feels like cargo cult design thinking. We have zero new insights after reading the whole piece.
Sounds like the problem is a failed government that can’t provide reliable base-load electricity generation. But the article acts like its citizens fault, we should live in a third world country and everyone should adapt by using wet towels or fans or something. Utter nonsense that provides no answers or real solutions.
The houses were shaded, the walls were vertical slats with gaps to allow air flow, and they kept their floors wet. It worked.
We prefer to make things excessively complicated.
I will say that everything engineers hate about “waterfall” development, local communities hate about technocratic top-down solutions raining down to “help them”.
I see a lot of comments here saying we need to fix the energy system, make distribution more reliable, add solar and DC air conditioning to houses. These solutions are valid and can do wonderful things for people in the right situations. We need to be conscious of the communities we’re serving when we make these proposals.
I worked with my city on a microgrid proposal last year for a low income part of the city. The project proposed solar, storage, rain water harvesting, and multimodal transportation, low cost reliable electricity. When I talked to members of the community where the project would go in they were totally against it. They told me that whenever the city plans projects like that, developers swarm in, buy up properties in the neighborhood, on the anticipation that the property values will go up, and raise rents, causing residents to need to leave.
The value of engaging communities and finding their solutions is that you build understanding of their needs. You also learn what they are already doing, which might be cheaper, more scalable, or more responsive than technical solutions by themselves.
Even the negative comments here are interesting!
I wish there were more articles about the warming in smaller cities and what can be done, to spark discussion and put more heads thinking about this.