@HoWill not always. In this case, I received 2D "generic" sections of a building, and I was to build more detailed versions of them. So it kind of made sense to start from the 2D drawing, because some parts would not change between the generic and detailed versions, and it's very easy to extrude stuff from these 2D drawings.
But in any case, when dealing with buildings, it's always good to have some 2D to start with, even if it is just the site plan. This depends on the person who does the design, though. I find it easier when I have something existing to start designing from, I am one of those who prefer to "start from the outside". Other designers will prefer the contrary, start from the inside.
Thanks! Nowadays unfortunately it's more and more rare that someone gives you good, strong arch critique... It's polypropylene. The greenhouse effect is actually something we count with, to produce air sucking and insert fresh air into the base of the house. If it gets too strong, though, there are things we can do afterwards, such as paint the roof tiles. Also, there should be trees all around. But I agree this is a critical issue, it will have to be studied with great care.
Your two other ideas are very good... We were thinking of having some external floor somewhere, I hadn't thought of putting it where the ramp is, simply! The masonry "house" might be suppressed, though...