That's what layer intersection priorities are all about. Check out the help menu.
Place your skirting in a layer with a different priority than the one used for your wall layer. High/low doesn't matter ... just not equal. (The word 'priority' is a bit of a misnomer.)
Karl
One of the forum moderators
AC 27 USA and earlier • macOS Ventura 13.6.6, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB