you know you don't have to stick with NURBS and that you can convert them to polys right?

not sure what a house needs with organic shapes... are you going to make a spherical roof with stylistic bumps and stuff?

i would have thought you'd want to start with a polygon box, extrude faces and draw new edges to get the walls of the house, then model the organic parts with NURBS and then convert them to polys, change the topology a bit so it makes a little more sense and then smooth

any part of the house that you'd be able to do in NURBS faster than in polys i'd convert after i'm done and sew the pieces together