You'll need to make use of a couple of cheats:
boolprop snapobjectstogrid false
boolprop allow45degreeangleofrotation true
moveobjects on (depending on other objects around, this may be needed)
Make sure after the object is placed to reverse these or placing windows and doors in build mod will be impossible.
Thank you but shall I use them all?? and do they only work in the lot I am in or shall I do it over again when visiting a new lot(house)