Index: Ringtoets/Piping/src/Ringtoets.Piping.IO/Builders/SoilLayer2D.cs
===================================================================
diff -u -rda35dc04febd3e2d23219523816803040b9d4349 -r7ae9100ff4e61169edcefaeb01b72d492431742f
--- Ringtoets/Piping/src/Ringtoets.Piping.IO/Builders/SoilLayer2D.cs	(.../SoilLayer2D.cs)	(revision da35dc04febd3e2d23219523816803040b9d4349)
+++ Ringtoets/Piping/src/Ringtoets.Piping.IO/Builders/SoilLayer2D.cs	(.../SoilLayer2D.cs)	(revision 7ae9100ff4e61169edcefaeb01b72d492431742f)
@@ -115,8 +115,7 @@
             var result = new Collection<PipingSoilLayer>();
             if (OuterLoop != null)
             {
-                IEnumerable<double> outerLoopIntersectionHeights = GetLoopIntersectionHeights(outerLoop, atX);
-
+                double[] outerLoopIntersectionHeights = GetLoopIntersectionHeights(outerLoop, atX).ToArray();
                 if (outerLoopIntersectionHeights.Any())
                 {
                     IEnumerable<IEnumerable<double>> innerLoopsIntersectionHeights = InnerLoops.Select(loop => GetLoopIntersectionHeights(loop, atX));