If the Roof covers the Wall (the screen shot is dark and hard to read), use a Solid Element Operation (SEO): select the Wall as Target, the Roof as Operator, and the execute a Subtraction with Upward Extrusion.
David
David Maudlin / Architect www.davidmaudlin.com Digital Architecture AC29 USA Perpetual • Mac mini M4 Pro OSX15 | 64 gb ram • MacBook Pro M3 Pro | 36 gb ram OSX14