Flooring outwith internal room

Hi all, not often I do a rendered Birds Eye View Floor Plan but trying to demonstrate different layouts to my client and why an island wouldn't work. You can see the flooring is bleeding outwith the internal walls, to the outside. Does anyone know why its doing this and how this can be fixed or is it always this way?

Are you meaning the triangular floor sections?... normal I think... there is a setting... something like "encapsulate room" in the 3D options that could affect this happening...

got it thanks daz, its in advanced options > environment > encompassing floor and ceiling

That's much better as it was very distracting in birds eye view. Thank you both.

Yes, thank you! 
It sort of bothered me but i just lived with it, i didn't know there was a fix!