It’s way cheaper to paint the roof white. Not kidding.
Black absorbs light from the sun while white reflects light, meaning white materials get less hot. Painting a roof white is extremely cheap (10s to 100s for a standard roof) and good paint can last for years. You can also save labor costs by doing it yourself. Studies have found painting a roof white saves 10 – 20% on energy bills too due to less AC usage.
This is why a lot of businesses paint their roofs white, because operational costs are a fundamental part of running a business. If it saves energy bills then you increase profit. Ever look at a commercial zone from sat. view? That’s why all the Wal-Marts and Home Depots and shopping malls are white.
Compare that to a “roof umbrella” which sounds pretty over engineered and probably costs a ton in labor.
source: did a term paper on this very subject
P.S. we (as a society) have also invested a ton of resources into developing more efficient and heat-reflective roof materials themselves. Shingles, tiles, stuff like that. But that’s way more complicated than paint.
The roof is the umbrella. It blocks the sun, and then the attic is insulated from the rest of the house and ventilated to help transport the hot air away. Reflective materials can help, too.
awnings can reduce energy usage from AC, because they safe the windows. But shedding the roof is basically just adding an extra layer of roof. To it’s less effective they just adding terminal insulation.
Roof top solar panels can reduce energy usage from AC because they divert energy from getting to the house.
This is somewhat common for “mobile homes” (house trailers). Mobile homes are not very well insulated and are built like ovens (metal exterior, insulation, interior walls/ceiling with very little gap). As they age, they are also prone to leaking water. Many of the mobile homes I’ve seen are under a “roof” several feet above the trailer. Keeps it cooler and protects it from rain, hail, etc.
Shade trees around the house, plus overhanging eaves, are a much nicer answer. You get to listen to the birds singing, it’s shady outdoors, you get free oxygen …
I just saw a house like you describe in the Zillowgonewild sub. It was about a week ago. The whole house had a cover over it. I thought it was really cool. IIRC it had solar panels on top.
I wondered the same thing after having to cut down the last remaining tree that gave shade to my house. But I don’t see how a giant shade/umbrella would be able to withstand wind and storms.
Seriously, I think that other technology —insulation, roof venting, thermal windows, for example—do the job better and work for cold temperatures as well as warm.
A properly insulated and vented roof acts exactly like a very sturdy umbrella, but way better. It stops rain. Insulation stops heat transfer in and out. The ventilation prevents over heating in the summer and keeps the roof surface cold in freezing temperatures to prevent ice dams.
You could try awnings. They work like shade umbrellas for your windows. You get the lion’s part of the light while blocking most of the heat. There’s a youtuber called technology connections that does a video about them. You should give it a look.
My solar panels actually do act as that umbrella. They’re above the roof and air flows freely beneath them, and they shade nearly the entire roof. And then the attic itself, as others have mentioned, also serves that role a little bit. But there’s really not a whole lot of airflow through it, so it does heat up quite a bit. If you’re expecting the attic to shade rather than bake, you’ve got a very different attic than mine.
Can’t we think of something better like umbrella from trees. They do tend to be very effective at collecting sunlight, are beautiful to look at and don’t stop sunlight during winters. Who knows might be the perfect solution.
doubled up roofs with large air gaps like this are probably actually very effective. I’m assuming the practical costs vs benefits + the fact that it’s hard to make it look good mean its just not worth it in most cases. I’m sure in super hot environments with lots of solar irradiance it would pay off though.
A lot of roofs in Medellín Colombia have a little tarp or cloth strung up on a little metal structure on the roof. By day it keeps the sun off the roof of the building to keep it colder, by night it traps the warmth a little bit and makes it a nice and cosy place to have some drinks.
People all arguing against that idea while many mates living in a roof apartment would probably die for a 1000$ big roof umbrella covering them from the sun. I think the idea is cool.
I need the AC particularly for my electronics. Also, whenever humidity takes off. Just having shade does nothing. Trying to draw anything in my office at home when it’s humid without AC is just futile.
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My roof is the umbrella, is it not? I have roof vents and insulation under the roof to try to keep heat or cold in the attic from affecting the house.
It’s way cheaper to paint the roof white. Not kidding.
Black absorbs light from the sun while white reflects light, meaning white materials get less hot. Painting a roof white is extremely cheap (10s to 100s for a standard roof) and good paint can last for years. You can also save labor costs by doing it yourself. Studies have found painting a roof white saves 10 – 20% on energy bills too due to less AC usage.
This is why a lot of businesses paint their roofs white, because operational costs are a fundamental part of running a business. If it saves energy bills then you increase profit. Ever look at a commercial zone from sat. view? That’s why all the Wal-Marts and Home Depots and shopping malls are white.
Compare that to a “roof umbrella” which sounds pretty over engineered and probably costs a ton in labor.
source: did a term paper on this very subject
P.S. we (as a society) have also invested a ton of resources into developing more efficient and heat-reflective roof materials themselves. Shingles, tiles, stuff like that. But that’s way more complicated than paint.
The roof is the umbrella. It blocks the sun, and then the attic is insulated from the rest of the house and ventilated to help transport the hot air away. Reflective materials can help, too.
awnings can reduce energy usage from AC, because they safe the windows. But shedding the roof is basically just adding an extra layer of roof. To it’s less effective they just adding terminal insulation.
Roof top solar panels can reduce energy usage from AC because they divert energy from getting to the house.
this guy does NOT hurricane.
This is somewhat common for “mobile homes” (house trailers). Mobile homes are not very well insulated and are built like ovens (metal exterior, insulation, interior walls/ceiling with very little gap). As they age, they are also prone to leaking water. Many of the mobile homes I’ve seen are under a “roof” several feet above the trailer. Keeps it cooler and protects it from rain, hail, etc.
Double roofs exist, especially in the tropics.
https://architropics.com/double-roof-for-cooler-house/
Shade trees around the house, plus overhanging eaves, are a much nicer answer. You get to listen to the birds singing, it’s shady outdoors, you get free oxygen …
Wind, maintenance, aesthetics… Frankly, white painted/tiled roofs would help a lot, again, aesthetics, people think they look off.
I just saw a house like you describe in the Zillowgonewild sub. It was about a week ago. The whole house had a cover over it. I thought it was really cool. IIRC it had solar panels on top.
Ooh here it is: https://www.reddit.com/r/zillowgonewild/comments/1kats15/beat_the_desert_heat_with_a_whole_house_awning/
or just go to the zillow listing https://www.zillow.com/homedetails/8095-Scholl-Rd-Morongo-Valley-CA-92256/17489792_zpid/ I don’t see solar panels on top but it says they have solar and I don’t see panels so they’re probably on top.
That’s what trees are for 🙂
Absolutely if you could prevent the wind from doing uplift, the vortex between two surfaces would create enormous uplift..
If you could afford the engineering and extra build cost this would be phenomenal ways of keeping heat out
They make excellent kites
I wondered the same thing after having to cut down the last remaining tree that gave shade to my house. But I don’t see how a giant shade/umbrella would be able to withstand wind and storms.
Wind
They are called Tropical Roofs.
Roof umbrella = a roof.
wind
Ours are called trees.
Tents have flys so why can’t houses? You’d call it a house fly.
That’s what front porches, eaves, and attics were for.
Wind
They are a thing. They are called “trees” 😉
Seriously, I think that other technology —insulation, roof venting, thermal windows, for example—do the job better and work for cold temperatures as well as warm.
It’s called insulation.
I took some classes on architecture (UCLA, many many years ago) got some of the responses here (trees, light colored shingles and insulation).
It makes sense, but I still want houses to look like massive tents (granted in the hotter climates).
We do use umbrellas to cool houses! We call them trees.
A properly insulated and vented roof acts exactly like a very sturdy umbrella, but way better. It stops rain. Insulation stops heat transfer in and out. The ventilation prevents over heating in the summer and keeps the roof surface cold in freezing temperatures to prevent ice dams.
You could try awnings. They work like shade umbrellas for your windows. You get the lion’s part of the light while blocking most of the heat. There’s a youtuber called technology connections that does a video about them. You should give it a look.
Shade sails are a thing
Wind
Shade trees. I have a large maple that blocks the western sun from about 1/2 my house. Helps a lot with cooling costs in summer.
My solar panels actually do act as that umbrella. They’re above the roof and air flows freely beneath them, and they shade nearly the entire roof. And then the attic itself, as others have mentioned, also serves that role a little bit. But there’s really not a whole lot of airflow through it, so it does heat up quite a bit. If you’re expecting the attic to shade rather than bake, you’ve got a very different attic than mine.
Ceilings used to be the roof. Then we started building roofs on top of the ceiling, and now we all have attics. So we already do have double roofs.
They’re called trees.
Intall some eyehooks and use some Aluminet to keep sun of the sunny side of your structure.
It turns into a wind sail.
This is done and a good idea in my opinion. Look up “pole barn over mobile homes”
Plant some tall trees
My attic temps dropped by about 10 degrees after solar panels were installed. I guess this has the same effect as an umbrella
Think about how huge one would need to be to shade a whole house. Then think about what happens when the wind grabs it and yoinks if from your roof?
Can’t we think of something better like umbrella from trees. They do tend to be very effective at collecting sunlight, are beautiful to look at and don’t stop sunlight during winters. Who knows might be the perfect solution.
Isn’t that the purpose of the roof, to shield the house from elements? Double roof house, a roof to protect another roof?
doubled up roofs with large air gaps like this are probably actually very effective. I’m assuming the practical costs vs benefits + the fact that it’s hard to make it look good mean its just not worth it in most cases. I’m sure in super hot environments with lots of solar irradiance it would pay off though.
Pain the roof white. Increases the amount of light that’s reflected back as short wave energy as opposed to long wave “felt” heat evergy.
Probably too hard to maintain. It’d be much eaxier to add more insulation, and paint the roof a light color. And most pkaces won’t even do that.
Plant trees, works like an umbrella and looks good!
Go put a giant umbrella or several smaller umbrellas on your roof and tell us how that goes.
A lot of roofs in Medellín Colombia have a little tarp or cloth strung up on a little metal structure on the roof. By day it keeps the sun off the roof of the building to keep it colder, by night it traps the warmth a little bit and makes it a nice and cosy place to have some drinks.
People all arguing against that idea while many mates living in a roof apartment would probably die for a 1000$ big roof umbrella covering them from the sun. I think the idea is cool.
Awnings are what you’re asking for.
While helpful, for me that doesn’t cut it.
I need the AC particularly for my electronics. Also, whenever humidity takes off. Just having shade does nothing. Trying to draw anything in my office at home when it’s humid without AC is just futile.
I’ve seen mobile homes that are covered in a car port like structure.