Hello
Are you wanting to make cc walls and floors?
If you do, you can use the Sims 4 Studio tool to create them.
http://sims4studio.com
These are links to tutorials on creating them
http://sims4studio.com/thread/108
http://sims4studio.com/thread/579
This is a link to a variety of Build Mode cc guides
http://sims4studio.com/thread/645/index-custom-content-tutorials-build
You need to register on the site to download the Sims 4 Studio tool but it is free. You need to be logged in to access the download page.