Thanks for replying, a couple more questions if that's ok...
1) Give the walls some thickness with a shell modifier. Have the shell go outside instead of inside so you don't make the room smaller.
Should this be inside instead of outside to avoid the walls growing outwards and making the room smaller?
2) Copy the walls object to use for a boolean.
3) Save
4) Boolean the floor out with the walls copy, adjust the settings as needed.
4b) Delete any faces that were outside of the boolean.
5) Go back to your original walls that now have thickness
6) Delete out some faces to create a door. Make sure to delete on both sides of the wall.
7) Select the edges on both sides of the new door gap and bridge them.
Select the hard edges on one side of the wall and "Create Shape from Selection". Use linear.
9) Give that spline some thickness and 4 sides so it looks like a frame, then scale it to fit the door right and reset the xform.
Is the hard edge my spline in this instance?
Would this be 3 sides as it's a traingular door?
How do I reset the x-form?
I'd still be looking to create another identical door on the opposite side of the room, how would you do this please?
all best
Luke