My house is hot in the southern United States. Trying to add insulation in the attic space during the summer almost killed me last year. The attic was so unbelievably hot. I have developed a roof leak and was thinking about a metal roof on top of my current roof. I was wondering why a metal roof can’t be installed on braces a few inches above an existing roof to function as a roof and shade. The airflow between the two would have to cool the attic, much better than if the heat radiated through straight to the shingles and plywood. We bought a sunshade for our back patio, and I’ve thought about even something as simple as that over smaller homes could drastically help.
In: Engineering
You can get a similar effect to what you’re looking for by making sure the roof is well ventilated. Where I work, new homes have a minimum amount of venting at the top and bottom of the roof.
[Like so](https://cdn-dlagh.nitrocdn.com/AeZzohDGsaPHNVvkMMRIfcUGplvIuxeG/assets/images/optimized/rev-7355784/absoluteroof.ca/wp-content/uploads/2016/03/roof-air-flow.jpg)
Here’s a [22 minute](https://youtu.be/uhbDfi7Ee7k?si=AHZhh1_4rWQU1pqg) video explaining why Awnings are the solution you are looking for
What you want is some trees.
They provide that shade, along with other benefits, like windbreaking for winter. And they’re pretty weatherproof, unlike a giant shade structure.
It ain’t cheap, but an aluminum shingle roof is amazing for thermal load. Plus will easily last 50 + years.
Trees are good for this. We have a big tree on the south side of our house and it’s totally noticeable how much it cools the rooms on that side.
Adding a metal layer a few inches above your roof may create a situation where you can’t extinguish a fire due to the metal, while also creating a chimney effect that pulls in air at the lower end as heat and smoke pours out higher up.
This is actually what solar panels end up doing. People say their house is cooler, even if you had broken solar panels installed. I think it’s actually a huge miss in the design of houses.
ELI5 answer:
People used to design houses in ways that kept them cool (or warm) because electricity did not exist. They had to rely on techniques that were often unique to their region. For example in India where it is very hot for much of the year, in some multi-story buildings there are vents between the floors (in the hallway) of the same building. A breeze can go vertically through a building. They also install a fan intake and fan outtake in rooms (two windows) to create a sort of “cross breaze”.
As electricity and other means of heating/cooling your home became more common, problem began relying on those as their solution instead of other techniques that go back to ancient times.
they have shade sails at playgrounds over the kids play equipment. Most houses are too big to have one of those.
But where I think this idea would have real value is in cars.
If we have windscreen wipers for rain and snow tires for snow, why don’t cars also come with a built-in shiny thing they can put over themselves while parked outside in summer. That’s a luxury feature people would really value in some climates.
They are called trees.
Just kidding. I know that is not possible everywhere. But create a shady dry spot over your rough and you well have animals living up there in no time.
Although as I type this I had a brick house in So Indiana that the bedroom wall faced the setting sun. The brick would heat up and radiate heat into the house all night.
I started hanging 3 10×10 silver tarps from the eaves on sunny days and it made a world of difference.
Good idea. You just have to pick the right method for your property
I used to work in roofing. Don’t put metal over your shingles. The expansion in the winter time will cause major problems.
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