If you dont want to change the fill, so you can use the way that pbg mentioned step by step:1. Change uncut surface pen to -1 of elevation setting.2. Choose the lines & fills and send to back.3. Choose the wall and send to back.

You can select the wall and press Ctrl + C, then Ctrl + V. After that, you will have a filled wall cut with overlapping elements. You can then change the fill.