4 ms·

I was quite puzzled by the explanation given for the steps as well. At first I was thinking that perhaps they need a gutter per level due to rain coming in extr

by usrusr 4y ago

I was quite puzzled by the explanation given for the steps as well. At first I was thinking that perhaps they need a gutter per level due to rain coming in extremely short bursts, but that's clearly ruled out by the pictures. Perhaps it's not about throughput at all, only to limit inertia when the water eventually hits the gutter? Given the steep angles of the roofs that might cause some spillover loss otherwise. Then why are the roofs so steep? Could be building material: can a small island lacking bodies of water even have clay, for roof tiles? A thatched roof would be impractical for harvesting rainfall. And when you go limestone masonry (apparently the building material available), you'll likely end up with something steep. Steep and stepped, unless you go the extra mile chiseling for smoothness. So the original cause for the stepped nature of the roofs is kind of related to water harvesting (even if the hurricanes mentioned in passing have likely been just as motivational against organic materials), and the steps might actually help by preventing high inertia of water hitting the gutter, but I suspect that's more a convenient coincidence than the accrual reason.

kgermino 4y ago
Steep roofs also give you more height for hot air to rise. If they’re vented at the top (not sure but I assume yes) it will also help you get a chimney effect creating airflow through the house.
cmrdporcupine 4y ago
I seem to remember hearing some explanation like it was about maximizing the amount of time that the rainwater gets exposed to the limestone on the roof? For purification/pH balance purposes? The same kind of steps were used even for catchment areas that weren't on houses. I remember passing (on the bus) an area that had a whole hill set up with the same kind of stepped/terraced limestone that fed down into some sort of reservoir.
- usrusr 4y ago
  My intuition suggests that rainwater that has spent less time on the roof won't be worse than rainwater that had spent more time there, but this intuition could certainly be wrong. Regarding the landscape catchment, if it's not in-situ stone that is laid bare and chiseled into shape it might simply be an economy of scale thing, use roofing commodity instead of reinventing the wheel. And if it's in-situ limestone, a major contributor to the decision for stepped/terraced might still be ease of maintenance access. The chemical qualities seem more like a convenient coincidence to me. Perhaps an enabling quality in absence of which they'd have long switched to desalination, but even that would not make it a causal "why". Particularly the part about UV working better with the reflections white making photons pass twice seems doubtful to me, because nighttime rain is probably not entirely unheard of (yeah, I might be wrong about this)

by usrusr 4y ago

kgermino 4y ago

Steep roofs also give you more height for hot air to rise. If they’re vented at the top (not sure but I assume yes) it will also help you get a chimney effect creating airflow through the house.

cmrdporcupine 4y ago

I seem to remember hearing some explanation like it was about maximizing the amount of time that the rainwater gets exposed to the limestone on the roof? For purification/pH balance purposes? The same kind of steps were used even for catchment areas that weren't on houses. I remember passing (on the bus) an area that had a whole hill set up with the same kind of stepped/terraced limestone that fed down into some sort of reservoir.

usrusr 4y ago
My intuition suggests that rainwater that has spent less time on the roof won't be worse than rainwater that had spent more time there, but this intuition could certainly be wrong. Regarding the landscape catchment, if it's not in-situ stone that is laid bare and chiseled into shape it might simply be an economy of scale thing, use roofing commodity instead of reinventing the wheel. And if it's in-situ limestone, a major contributor to the decision for stepped/terraced might still be ease of maintenance access. The chemical qualities seem more like a convenient coincidence to me. Perhaps an enabling quality in absence of which they'd have long switched to desalination, but even that would not make it a causal "why". Particularly the part about UV working better with the reflections white making photons pass twice seems doubtful to me, because nighttime rain is probably not entirely unheard of (yeah, I might be wrong about this)