Cannot subdivide face anymore?

See my problem in this video. Not a bug apparently…

You probably have extra verts still attached to the edges of the offending faces. Turn on vertex select to check for them.

Those look like ngons. Before subdividing a mesh you either need to add edge loops that continue up and over the roof. Or begin to separate the faces into other objects (P in edit mode). Or the best thing I think is to knife the edge to separate it that way (V in edge select edit mode). This way you keep the quads.