diff --git a/src/util/qpolygon-utils.js b/src/util/qpolygon-utils.js
index b780cdd9..fd02cf05 100644
--- a/src/util/qpolygon-utils.js
+++ b/src/util/qpolygon-utils.js
@@ -1345,7 +1345,7 @@ export const drawRidgeRoof = (roofId, canvas, textMode) => {
             }
           }
 
-          if (!roof.inPolygon({ x: oppositeMidX.toNumber(), y: oppositeMidX.toNumber() })) {
+          if (!roof.inPolygon({ x: oppositeMidX.toNumber(), y: oppositeMidY.toNumber() })) {
             const checkEdge = {
               vertex1: { x: oppositeMidX.toNumber(), y: oppositeMidY.toNumber() },
               vertex2: { x: currentMidX.toNumber(), y: currentMidY.toNumber() },