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Comment on anons brother has some strong opinions

Cort@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

It is lighter and cheaper, as you can use thinner materials. This is because pointy is a stronger shape than flat.

It gives more interior space.

If you’re using lighter cheaper materials you’ll need all the added interior space for roof trusses, none of it will be livable space.

It allows more sunlight to reach the street.

No, for the same amount of occupiable space the shorter flat roof blocks less light than a standard 10:12 or 12:12 roof

It has a smaller area-to-volume-ratio through which heat can escape.

The greater surface area of a pitched roof means this is absolutely not true. The hypotenuse is always longer than either leg.

Solar panels get a higher efficiency.

This one actually depends on latitude, equatorialy it’s better flat. And don’t forget that the minimum summer angle is limited by the pitched roof.

If a city has the same height restrictions for flat roofed buildings as for pointy roofed buildings, and the architect is too lazy to go to the city council to explain to them that that doesn’t make sense, the architect can design a building with more volume by making the roof flat.

No it makes perfect sense. It goes back to your comment on letting sunlight through to the street. The maximum height is the maximum height so everyone gets the same amount of light.

In other words: ~~the only reason any architect would design a building with a flat roof is because they are either lazy or they have no idea what they are doing.~~ this guy thinks their habitat is the only kind over the whole planet and can’t imagine people living in areas where snow load wouldn’t need to be considered.

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JackbyDev@programming.dev ⁨3⁩ ⁨weeks⁩ ago
More non livable space would’ve been nice in my attic recently. I was trying to diagnose a potential leak, but the chimney is in the corner of the house, so not only do I have to walk across the rafters, but I have to squat down in the corner to even begin to be able to peak at the chimney pipe. But that’s a very niche scenario. I just sort of dislike the idea of void in houses, I think it should all be accessible to an extent.

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TheLazyNerd@europe.pub ⁨1⁩ ⁨week⁩ ago

If you’re using lighter cheaper materials No, I’m using the same materials. sloped roofs are simply a stronger geometry, allowing roofs to be cheaper and lighter by using less material.

No, for the same amount of occupiable space the shorter flat roof blocks less light than a standard 10:12 or 12:12 roof Incorrect. While the highest point of a sloped roof is higher than the highest point of a flat roof, the lowest point is lower. This means that for medium high sun angles sloped roofs provide won’t block the sunlight, while flat roofs do, and for low sun angles it is the other way around. However, there is not much sunlight anyway at low angles.

The greater surface area of a pitched roof means this is absolutely not true. The hypotenuse is always longer than either leg. That’s a basic math fail. The highest volume-to-surface-area-ratio is achieved in a spherical design, A slope roof that has a less than 45 degree angle is closer to a sphere.

Do you have any real disadvantages of sloped roofs?

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ulterno@programming.dev ⁨3⁩ ⁨weeks⁩ ago

snow load

Now I am kinda curious about how heavy snow can get.

I live in a snow-less flat-roofed region and the load capacity seems to be ~1.5 kN/m² ^[engineeringtoolbox.com/simply-supported-slabs-loa…]. So, even the cheapest compliant (maybe I should be checking govt. docs for compliance values) building not designed for snowfall should be able to manage 15cm of rain/snow.

Well, that is much lower than the 1m of snow that I would expect building up in case it really snows and it could get higher considering the parapet walls tend to ~1m high.

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- bilb@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago
  Snow itself can get pretty heavy, but more risky I think is repeated melting and refreezing. You can wind up with a large mass of ice that can really fuck up a roof or overhang.
  
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  - ulterno@programming.dev ⁨2⁩ ⁨weeks⁩ ago
    Well, I have seen drains clog up so bad that the parapets act like a bowl and capture the ~1m of water with the roof still staying mostly intact (although seepage would have greatly increased there), so something other than my calculations is holding up that roof.
    
    So I guess one would have to rely on the melting-refreezing to break down the roof, considering that without the phenomenon, the ice would be pretty fluffy and light.
    
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