Hi, I'm an absolute newbie but have managed to cobble together a drawing. My problem is that I have a surface which although appears to have all lines connected, when I try to edit or insert a window or opening, the surface appears not to be solid? The drawing was alright until I tried to add another window and create different panels to reflect the brick and tile surfaces. The attached file is a copy of the offending wall only and not the main drawing. I had "grouped" it together to see if I could make it solid and then insert it back to the main drawing and "explode". I'm sure this is a really amateur way to do it, but clearly lack the knowledge to create what I want!

wall.skp