I have a finished floor plan with 5.5" thick walls, but now i want to make all my walls thicker without changing the size of my rooms. Does anyone know what i can do to achieve this. I tried locking the wall dimensions before changing their thickness but it still shrunk my room sizes. Maybe i did it wrong, idk, can someone help?
Yes it is fairly simple to do what you want. Before you change the wall type/thickness Click on the wall to highlight it, first notice which side of the wall the up and down arrows are that indicates the exterior side of the wall, then in the properties panel, click on the location line and highlight, Finish Face : Interior this locks the interior side of the wall so when it moves it will move out from that point. try it out on a few walls to see the results. exterior walls the wall will move out outside of the exterior. Pay close attention when working with interior walls again the double arrow will indicate what is considered the exterior side of the wall so you will need to highlight the location line for the side that you do not want to move. Hope this helps!
its good to know that you have got answer to your query and i hope you'd completed your floorplan with changes wall thickness.
Just to add my opinion on this issue, You have to take take care of location line for each individual wall.
Drawing a wall from left to right and right to left have different meanings in Revit (clockwise/anti-clockwise).
Please make sure you did it right way as suggested by experts in previous answers.