How can I achieve slightly curved roofs

I currently have the top roof, I’m trying to achieve the bottom roof. I don’t want it that smooth though, not curvy to the point that it looks unrealistic. I tried creating a 90 degree arch that is 128x256, but it wasn’t proportioned properly. I’m wondering if there’s a certain technique involved in creating this type of roofing. If so, could someone kindly explain it to me?

I have never seen a roof like this in my life…

Could you please give some real life examples as to what you’re trying to achieve?

Try displacements.

Displacements and vertex manipulator.

I have a VMF for you in case you want to see how it’s done.

Although the ones I have here are a bit unrealistic due to the art style.

Real life example:

While on the subject of weird roofs, is this possible in hammer:

Yes, but it would have to be func_detail-ed.

And Source doesn’t like concave brushes, so displacements would be your best bet (for the pagoda roof I mean).

Oh, Those kinds.

I thought by your screenshots you wanted a flat roof on top and a curved roof underneath it.